ae 2035-qb

Prof. G. Prabhakaran AE 2035/ AE 1014 Air Traffic Control and Planning

Department of Aeronautical Engineering, Jeppiaar Engineering College 1

JEPPIAAR ENGINEERING COLLEGE

DEPARTMENT OF AERONAUTIAL ENGINEERING

AE 2035 - AIR TRAFFIC CONTROL AND PLANNING

SYLLABUS

AE 2035 AIR TRAFFIC CONTROL AND PLANNIN G 3 0 0 100 OBJECTIVE

To study the procedure of the formation of aerodrome and its design and air traffic control. 1. BASIC CONCEPTS 9

Objectives of ATS - Parts of ATC service – Scope and Provision of ATCs – VFR & IFR operations – Classification of ATS air spaces – Varies kinds of separation – Altimeter setting procedures – Establishment, designation and identification of units providing ATS – Division of responsibility of control. 2. AIR TRAFFIC SERVICES 9

Area control service, assignment of cruising levels minimum flight altitude ATS routes and significant points – RNAV and RNP – Vertical, lateral and longitudinal separations based on time / distance –ATC clearances – Flight plans – position report 3. FLIGHT INFORMATION ALERTING SERVICES, COORDINATI ON, EMERGENCY

PROCEDURES AND RULES OF THE AIR 10

Radar service, Basic radar terminology – Identification procedures using primary / secondary radar – performance checks – use of radar in area and approach control services – assurance control and co-ordination between radar / non radar control – emergencies – Flight information and advisory service – Alerting service – Co-ordination and emergency procedures – Rules of the air. 4. AERODROME DATA, PHYSICAL CHARACTERISTICS AND OB STACLE

RESTRICTION 9

Aerodrome data - Basic terminology – Aerodrome reference code – Aerodrome reference point – Aerodrome elevation – Aerodrome reference temperature – Instrument runway, physical Characteristics; length of primary / secondary runway – Width of runways – Minimum distance between parallel runways etc. – obstacles restriction. 5. VISUAL AIDS FOR NAVIGATION, VISUAL AIDS FOR DE NOTING OBSTACLES

EMERGENCY AND OTHER SERVICES 8

Visual aids for navigation Wind direction indicator – Landing direction indicator – Location and characteristics of signal area – Markings, general requirements – Various markings – Lights, general requirements – Aerodrome beacon, identification beacon – Simple approach lighting system and various lighting systems – VASI & PAPI - Visual aids for denoting obstacles; object to be marked and lighter – Emergency and other services.

TOTAL: 45

TEXT BOOK

1. AIP (India) Vol. I & II, “The English Book Store”, 17-1, Connaught Circus, New Delhi.

REFERENCES

1. “Aircraft Manual (India) Volume I”, latest Edition – The English Book Store, 17-1, Connaught Circus, New Delhi.

2. “PANS – RAC – ICAO DOC 4444”, Latest Edition, The English Book Store, 17-1, Connaught Circus, New Delhi.



ANNA UNIVERSITY QUESTION BANK.

PART-A

UNIT I

1. What is Air Traffic Control? Ans: Air Traffic Control, a generic term meaning variously, area control centre, approach control unit or aerodrome control tower. Air traffic control (ATC) is a service provided by ground based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is:

• To separate aircraft to prevent collisions • To organize and expedite the flow of traffic • To provide information and other support for pilots when able.

2. What is the role of Air traffic controller in ATC? Ans: Air traffic controllers are the people who operate the air traffic control systems to expedite and maintain a safe and orderly flow of air traffic and help prevent mid‐air collisions. 3. Define Aerodrome. Ans: A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft. 4. What is meant by Controlled and Uncontrolled Airspace? Ans: Controlled air space: an air space of defined dimensions within which air traffic control service is provided to aerodrome traffic with airspace classification. Controlled air space which covers ATS airspaces classes A, B, C, D and E. Un-Controlled air space: an airspace where an Air Traffic Control (ATC) service is not deemed necessary or cannot be provided for practical reasons. According to the airspace classes set by ICAO both class F and class G airspace are uncontrolled. It is the opposite of controlled airspace. ATC does not exercise any executive authority in uncontrolled airspace, but may provide basic information services to aircraft in radio contact. Flight in uncontrolled airspace will typically be under VFR. Aircraft operating under IFR should not expect separation from other traffic: however in certain uncontrolled airspace this might be provided on an 'as far as is practical' advisory basis. 5. What is IFR flight? Ans: IFR flight: a flight conducted in accordance with the instrument flight rules. Instrument flight rules (IFR) are regulations and procedures for flying aircraft by referring only to the aircraft instrument panel for navigation. 6. What is VFR flight? Ans: VFR flight: a flight conducted in accordance with visual flight rules. Visual flight rules (VFR) are a set of regulations which allow a pilot to operate an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.



7. State the difference between VFR & IFR operation Ans: S. No

VFR Operation S. No

IFR Operation

1 Pilot navigates and flies by looking out the window

1 Pilot navigates using instruments in the cockpit

2 He uses the view out the window to keep the aircraft straight and level, and he navigates from place to place by looking at things on the ground (roads, rivers, buildings, etc.)

2 It is not necessary for him to look out the window, and in fact a pilot flying IFR can fly to his destination even if the windows are covered by cardboard

3 Pilots also must keep their eyes open for other airplanes nearby so that they don't hit anyone

3 IFR flights work in conjunction with air traffic controllers, who use radar to advise IFR flights of other aircraft in the area, thereby maintaining a safe distance between them.

4 VFR operation is not safer than IFR, because it cannot be carried out in any type of weather, by looking out window.

4 IFR is safer than VFR, because it can be carried out in any type of weather, regardless of visibility.

5 Flying IFR is not complicated. 5 Flying IFR is much more complicated than VFR, and requires much more training and practice.

8. State the objective of ATS. Ans: The objectives of the Air Traffic Services shall be to: a) Prevent collisions between aircraft. b) Prevent collisions between aircraft on the maneuvering area and obstructions on that area. c) Expedite and maintain an orderly flow of air traffic. d) Provide advice and information useful for the safe and efficient conduct of flights. e) Notify appropriate organizations regarding aircraft in need of search and rescue aid, and assist such organizations as required. 9. Describe the two basic types of flight rules. Ans: Instrument flight rules (IFR) are regulations and procedures for flying aircraft by referring only to the aircraft instrument panel for navigation Visual flight rules (VFR) are a set of regulations which allow a pilot to operate an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. 10. What are the tree components of ATC network? Ans: ATC system consists of 20 ARTCC (AIR ROUTE TRFFIC COTROL CENTRE) which has further divided into two types of control, one is approach control and other one is non approach control. An approach control tower with its associated TRACON provides separation and instrument landing services for IFR traffic and is also responsible for integrating VFR traffic into the approach pattern.



UNIT II 11. Give various division of Air traffic Services. Ans: The air traffic services comprise of three services identified as follows: 1. Air traffic control service - Area control service - Approach control service - Aerodrome control service 2. Flight information service 3. Alerting service 12. Mention different categories of Airports Ans:

1. International Airport 2. Domestic Air Carrier Airports 3. Commuter Airports 4. Reliever Airports

Or the following type also the answer can be given 1. Commercial Service Airports

a. Non-primary Commercial Service Airports b. Primary Airports

2. Cargo Service Airports 3. Reliever Airports

13. Differentiate TRACON and ARTCC Ans: Terminal Radar Approach Control - TRACON handles departing and approaching aircraft within its space. Air Route Traffic Control Centers (ARTCC) - There is one ARTCC for each center. Each ARTCC manages traffic within all sectors of its center except for TRACON airspace and local-airport airspace. 14. State the Airspace Classification followed in India. Ans: ATS airspaces in India are classified and designated in accordance with the following. Class D: IFR and VFR flights are permitted and all flights are provided with Air Traffic Control service, IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights. Class E: IFR and VFR flights are permitted; IFR flights are provided with Air Traffic Control service and are separated from other IFR flights. IFR flights receive traffic information in respect of VFR flights; Class F: IFR and VFR flights are permitted. All IFR flights receive an air traffic advisory service and all flights receive flight information service, if requested. Class G: IFR and VFR flights are permitted and receive flight information service if requested. Airspaces other than those in Class D, E and F have been classified and designated as class G airspace. [Explanation for understanding: Class D: IFR and VFR flights are permitted and all flights are provided with Air Traffic Control service, IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights. VFR flights receive traffic information in respect of all other flights. Airspaces in



terminal areas, control areas, control zones and aerodrome traffic zones have been classified and designated as class D airspace. Class E: IFR and VFR flights are permitted; IFR flights are provided with Air Traffic Control service and are separated from other IFR flights. IFR flights receive traffic information in respect of VFR flights; VFR flights receive traffic information in respect of all other flights, as far as is practical. Class E is not be used for control zones. Airspaces in designated ATS routes outside terminal areas, control areas and control zones, where air traffic control service is provided, have been classified and designated as class E airspace. Class F: IFR and VFR flights are permitted. All IFR flights receive an air traffic advisory service and all flights receive flight information service, if requested. Airspaces in designated ATS route segments outside terminal areas, control areas and control zones, where air traffic advisory service is provided, have been classified and designated as class F airspace. Class G: IFR and VFR flights are permitted and receive flight information service if requested. Airspaces other than those in Class D, E and F have been classified and designated as class G airspace. 15. Differentiate between the class D and Class E Airspace. Ans: Class D:

- IFR and VFR flights are permitted and all flights are provided with air traffic Control service, IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights.

- VFR flights receive traffic information in respect of all other flights. - Airspaces in terminal areas, control areas, control zones and aerodrome traffic

zones have been classified and designated as class D airspace. Class E:

- IFR and VFR flights are permitted; IFR flights are provided with air traffic control service and are separated from other IFR flights.

- IFR flights receive traffic information in respect of VFR flights; VFR flights receive traffic information in respect of all other flights, as far as is practical.

- Class E is not be used for control zones. - Airspaces in designated ATS routes outside terminal areas, control areas and

control zones, where air traffic control service is provided, have been classified and designated as class E airspace

16. Give the various ATC provision. Ans: The following are the responsibility for the provision of ATC: Area Control Service: The provision of air traffic control service for controlled flights, except for those parts of such flights which are under the jurisdiction of Approach Control or Aerodrome Control to accomplish following objectives: a) Prevent collisions between aircraft b) Expedite and maintain an orderly flow of air traffic Approach control service: The provision of air traffic control service for those parts of controlled flights associated with arrival or departure. Aerodrome control service:



The provision of air traffic control service for aerodrome traffic, except for those parts of flights which are under the jurisdiction of Approach Control. 17. What is meant by ATC Clearance? Ans: ATC clearance is an authorization for an aircraft to proceed under conditions specified by an air traffic control unit. Clearance may be prefixed by the words “taxi”, “take off”, “departure”, “en-route”, “ approach” or “landing” to indicate the particular portion of flight to which the air traffic control clearance relates. 18. Give the separation rules followed in vertical airspace. Ans: The vertical air separation Minimum (VSM) shall be, Between the surface and an altitude of 29,000 feet (8,800 m), no aircraft should come closer vertically than 1,000 feet or 300 meters (in those countries that express altitude in meters), unless some form of horizontal separation is provided. Above 29,000 feet (8,800 m) no aircraft shall come closer than 2,000 feet (or 600 m), except in airspace where Reduced Vertical Separation Minima (RVSM) can be applied.

Or (you can write as follows) The Vertical Air Separation Minimum (VSM) shall be,

(a) A nominal 300 m (1000 ft) below FL 290 and a nominal 600 m (2000 ft) at or above this level except for in (b) below and

(b) Within designated airspace, subjected to a regional air navigation agreement: a nominal 300 m (1000 ft) below FL 410 or a higher level where so prescribed for use under specified conditions, and a nominal 600 m (2000 ft) at or above this level.

19. Give the separation rules followed in horizontal airspace. Ans: If any two aircraft are separated by less than the vertical separation minimum, then some form of horizontal separation must exist. Ie.,

- Procedural separation - Lateral separation - Longitudinal separation

Or a. other minima for use in circumstances not prescribed: or b. additional conditions to those prescribed for the use of a given minimum:

20. Give the separation rules followed in Lateral Airspace. Ans:

a. The distance between those portions of the intended routes for which the aircraft are to be laterally separated is never less than an established distance to account for navigational accuracies plus a specified buffer.

b. Lateral separation of aircraft at the same level is obtained by requiring operation on different routes or in different geographical locations as determined by visual observation by use of navigation aids or by use of area navigation equipment.

OR WRITE AS FOLLOWS: Lateral separation shall be applied so that the distance between those portions of the intended routes for which the aircraft are to be laterally separated is never less than an established distance to account for navigational inaccuracies plus a specified buffer. This buffer shall be determined by the appropriate authority and included in the lateral separation minima as an integral part thereof.



Lateral separation of aircraft is obtained by requiring operation on different routes or in different locations as determined by visual observation, by the use of navigation aids or by the use of area navigation (RNAV) equipment. When information is received indication navigation equipment failure or deterioration below the navigation performance requirements. ATC shall then, as required, apply alternative separation methods or minima 21. State the longitudinal separation based on time between two aircrafts in Indian FIR Ans: Aircraft at the same cruising level – aircraft flying on the same track:

1. 15 minutes or 2. 10 minutes if navigation aids permit frequent determination of position and

speed 3. 5 Minutes in the following cases provided that in each case the preceding aircraft

is maintaining a true airspeed of 37 km/h (20kt) or more faster than the succeeding aircraft: (a) between aircraft that have departed from the same aerodrome: (b) between en-route aircraft that have reported over the same exact reporting point

22. Explain various parts of Flight plan. Ans:

i. validity period of the flight plan ii. days of operation iii. aircraft identification iv. aircraft type and turbulence category v. MLS capability

vi. Departure aerodrome vii. Off block time viii. Cruising speed (s) ix. Cruising level (s) x. Route to be followed

xi. Destination aerodrome xii. Total estimated elapsed time xiii. Indication of the location where the following information may be obtained

immediately upon request: 1. alternate aerodromes 2. fuel endurance 3. total number of persons on board 4. emergency equipment 5. other information

23. Explain the position reports. Ans: A. Unless exempted by the appropriate ATS authority or by the appropriate air traffic services unit under conditions specified by that authority, a controlled flight shall report to the appropriate air traffic services unit, as soon as possible, the time and level of passing each designated compulsory reporting point, together with any other required information. Position reports shall similarly be made in relation to additional points when requested by the appropriate air traffic services unit. In the absence of designated reporting points, position reports shall be made at intervals prescribed by the appropriate ATS authority or specified by the appropriate air traffic services unit.



B. Controlled flights providing position information to the appropriate air traffic services unit via data link communications shall only provide voice position reports when requested. Or write as follows On routes defined by designated significant points, position reports shall be made by the aircraft when over or as soon as possible after passing, each designated compulsory reporting point. Additional reports over other points may be requested by the appropriate ATS unit. Contents of voice position reports: 1) Aircraft identification 2) Position 3) Time 4) Flight level or altitude, including passing level and cleared level if not maintaining the cleared level 5) Next position and time over 6) Ensuing significant point. 24. State flight plan. Ans: Flight plans are documents filed by pilots or a Flight Dispatcher with the local Civil Aviation Authority (e.g. DGCA in INDIA) prior to departure.

Or Flight plan as filed with an ATS unit by the pilot or designated representative, without any subsequent changes. 25. Define RNAV & RNP Ans: RNP- Radio Navigation Performance: is type of performance based navigation (PBN) that allows an aircraft to fly a specific path between two or three dimensionally defined points in which accuracy necessary for operation within a defined airspace RNAV- Area Navigation: a method of navigation which permits aircraft operation on any desired flight path within the coverage of station referenced navigation aids or within the limits of capacity of self contained aids or a combination of these.



UNIT III

PSR – PRIMARY SURVEILLANCE RADAR SSR – SECONDARY SURVEILLANCE RADAR 26. What are identification procedures being used with primary radar? Ans: Where PSR is used for identification aircraft may be identified by one or more of the following procedures:

a. By correlating a particular radar position indication with an aircraft reporting its position over, or as bearing and distance from, a point shown on the situation display, and be ascertaining that the track of the particular radar position is consistent with the aircraft path or reported heading.

b. By correlating an observed radar position radar position indication with an aircraft which is known to have just departed, provided that the identification is established with in 2 Km (1NM) from the end of runway used. Particular care should be taken to avoid confusion with aircraft holding over or overflying the aerodrome or with aircraft departing from or making a missed approach over adjacent runways.

c. By transfer of radar identification d. By ascertain the aircraft heading, if circumstances require, and following a period of

track observation

27. State the separation standards in Secondary radar. Ans: Separation Standards in Secondary radar: • Radar used to separate aircraft – Reduces lateral and longitudinal separation minima – Increases throughput – Enhances safety – Better use of airspace • Vertical Separation – Aircraft below FL 290 • Separated by 1000 ft – Aircraft above FL290 • Separated by 2000 ft • Longitudinal Separation – Radar accuracy • 3nm within 40 nm radius of radar antenna • 5nm beyond 40nm radius of radar antenna – Wake Vortex Separation • Enroute and Approach • Landing • Lateral Separation – Radar accuracy • 3nm within 40 nm radius of radar antenna • 5nm beyond 40nm radius of radar antenna – Separation reduced for diverging paths 28. What is ARP? Explain in brief. (NB: no ARP is available question may be wrong so

answer is given for SARP) Ans: SARP – Standards and Recommended Practices are developed by ICAO and cover all technical and operational aspects of international civil aviation, such as safety, personnel licensing,



operation of aircraft, aerodromes, air traffic services, accident investigation and the environment. Whilst the PANS may contain material which may eventually become standards or Recommended practices (SARPs) when it has reached the maturity and stability necessary for adoption as such they may also comprise material prepared as an amplification of the basic principles in the corresponding SRPs, and designed particularly to assist the user in the application of those SRPs. 29. Give few basic radar terminologies. Ans: Radar, Target, Jamming, Range, Phase detector, Azimuth, MTI – Moving Target Indicator, MTD – Moving Target Detector. Synchronous detector, SRE –Surveillance Radar Equipment, PAR – Precision Approach Radar, Primary Radar, Secondary Radar, Doppler Navigation Radar, Ground Mapping Radar, Terrain Following Radar.

30. What is the basic principle of Radar? Ans: RADAR-Radio Detection and Ranging: Principle: • A signal, at constant intervals is sent through the area to be monitored using antennae. • Any object in the path of the signal reflects the part of the signal. • A receiver receives the signal which is translated into a dot on the CRO

31. How PAR is used to control air traffic? Ans: PAR – Precision Approach RADAR: PAR is designed for use as a landing aid rather than an aid for sequencing and spacing aircraft. PAR equipment may be used as a primary landing aid or it may be used to monitor other types of approaches. It is designed to display range, azimuth, and elevation information. Two antennas are used in the PAR array, one scanning a vertical plane, and the other scanning horizontally. Since the range is limited to 10 miles, azimuth to 20 degrees, and elevation to 7 degrees, only the final approach area is covered.

32. What is primary radar how it is used in identification of aircraft? Ans: Primary radar: a radar system which uses reflected radio signals. This type of radar (now called primary radar) can detect and report the position of anything that reflects its transmitted radio signals including, depending on its design, aircraft, birds, weather and land features. For air traffic control purposes, its targets do not have to co-operate, they only have to be within its coverage and be able to reflect radio waves, but it only indicates the position of the targets, it does not identify them. When primary radar was the only type of radar available, the correlation of individual radar returns with specific aircraft typically was achieved by the Controller observing a directed turn by the aircraft. Primary radar is still used by ATC today as a backup/complementary system to secondary radar, although its coverage and information is more limited

33. What is secondary radar how it is used in identification of aircraft? Ans: Secondary radar: a radar system wherein a radio signal transmitted from the radar station initiates the transmission of a radio signal from another station



The need to be able to identify aircraft more easily and reliably led to another wartime radar development, the Identification Friend or Foe (IFF) system, which had been created as a means of positively identifying friendly aircraft from enemy. This system, which became known in civil use as secondary surveillance radar (SSR) or as the air traffic control radar beacon system (ATCRBS), relies on a piece of equipment aboard the aircraft known as a "transponder." The transponder is a radio receiver and transmitter which receives on one frequency (1030 MHz) and transmits on another (1090 MHz). The target aircraft's transponder replies to signals from an interrogator by transmitting a coded reply signal containing the requested information. Both the civilian SSR and the military IFF have become much more complex than their war-time ancestors, but remain compatible with each other, not least to allow military aircraft to operate in civil airspace. SSR can now provide much more detailed information, for example, the aircraft's altitude, and it also permits the exchange of data directly between aircraft for collision avoidance. Given its primary military role of reliably identifying friends, IFF has much more secure (encrypted) messages to prevent "spoofing" by the enemy, and also is used on all kinds of military platforms including air, sea and land vehicles.

34. What is a performance check? Ans: The radar controller shall adjust the radar displays and carryout adequate checks on the accuracy thereof, in accordance with the technical instructions prescribed by the appropriate authority for the radar equipment concerned. The radar controller shall be satisfied that the available capabilities of the radar system as well as the information presented on the radar display(s) is adequate for the function to be performed. The radar controller shall report in accordance with local procedures, any fault in the equipment or any incident requiring investigation or any circumstances which make it difficult or impractical to provide radar services.

35. What is meant by flight advisory service? Ans: The en route flight advisory service (FAS), or Flight Watch, is a service from selected FSSs or AFSSs on a common frequency 122.0 MHz below flight level (FL) 180 and on assigned discrete frequencies to aircraft at FL180 and above. The purpose of EFAS is to provide en route aircraft with timely and pertinent weather data tailored to a specific altitude and route using the most current available sources of aviation meteorological information. Additionally, EFAS is a focal point for rapid receipt and dissemination of pilot reports.



UNIT IV

36. Explain few aerodrome reference codes. . Ans:

37. Draw the primary runway used in India. . Ans: (use any one diagram)

TORA - take off run available TODA - take off distance available ASDA - accelerate‐stop distance available LDA - landing distance available

38. Give few basic terminology used in aerodrome design. . Ans: Aerodrome elevation, aerodrome identification sign, aerodrome reference point, aerodrome reference field length, declared distances, TORA - take off run available, TODA - take off distance available , ASDA - accelerate‐stop distance available, LDA - landing distance available, displaced threshold, holding bay, instrument runway, primary runway, secondary runway, precision and non precision approach runway, landing area, intermediate holding position,



movement area, taxi way, aircraft stand taxi lane, apron taxiway, maneuvering area, RESA- runway end safety area, runway strip, RVR- runway visual range, Shoulder, stop way, threshold, touchdown zone, taxiway intersection, etc,. 39. What is meant by basic runway length? Describe three cases to be considered. Ans: Basic runway length: It is the length of runway under the following assumed conditions at the airport. 1. Airport altitude is at sea level. 2. Temperature at the airport is standard 15ºc 3. Runway is leveled in the longitudinal direction. 4. no wind is blowing on runway 5. Aircraft is loaded to its full loading capacity. 6. There is no wind blowing en route to the destination. 7. En route temperature is standard The runway length resulting when the actual runway length is corrected to the equivalent mean sea level, standard atmospheric pressure, and no gradient conditions.( or the three cases to be considered)

40. Give few obstacle restrictions. Ans: The following are the obstacle restrictions: Outer horizontal surface Conical surface Inner horizontal surface Approach surface Inner approach surface Transitional surface Inner transitional surface Balked landing surface Take off climb surface 41. Give few visual aids for denoting obstacles. Ans: Objects on Movement Areas

1. Vehicles and other mobile objects, excluding aircraft, on the manoeuvring area of an aerodrome are obstacles and shall be marked and, if the vehicle and aerodrome are used at night or in conditions of low visibility, lighted.

2. Elevated aeronautical ground lights within the movement area shall be marked so as to be conspicuous by day.

Objects on Runway Strips A fixed object located on a runway strip shall be marked and if the aerodrome is used at night, lighted, excluding visual aids that are by their nature visually conspicuous Other Objects A fixed object, other than an obstacle, adjacent to a take-off/approach surface should be marked and if the runway is used at night, lighted if such marking and lighting is considered necessary to ensure its avoidance except that the marking may be omitted when:

1. The height of the obstacle above the level of the surrounding ground does not exceed 150 m and it is lighted by medium intensity obstacle light by day; or

2. The object is lighted by high-intensity obstacle lights by day. All mobile objects to be marked shall be coloured or display flags.



42. Why there should be obstacle restrictions? Ans: The airspace around aerodromes to be maintained free from obstacles so as to permit the intended aero plane operations at the aerodromes to be conducted safely and to prevent the aerodromes from becoming unusable by the growth of obstacles around the aerodromes. This is achieved by establishing a series of obstacle limitation surfaces that define the limits to which objects may project into the airspace. Explanation for understanding An aerodrome operator is required to monitor the airspace around the aerodrome for infringement of the obstacle limitation surfaces by any object, building or structure. The aerodrome operator must take all reasonable measures to ensure that obstacles at or within the vicinity of the aerodrome are detected as quickly as possible. The aerodrome operator is required to inform the DCA immediately he becomes aware of the presence of an obstacle, giving details of its height and location and amended declared distances and gradients where applicable. In addition, where the aerodrome operator becomes aware of any development or proposed construction near the aerodrome that is likely to create an obstacle, he must inform the DCA as soon as practicable, giving all details of the likely obstacle.

43. Give the length of various primary and secondary runways. Ans: Primary Runway: The actual runway length to be provided for a primary runway shall be adequate to meet the operational requirements of the aero planes for which the runway is intended and shall be not less than the longest length determined by applying the corrections for local conditions to the operations and performance characteristics of the relevant Aero planes. Secondary Runway: The length of a secondary runway shall be determined similarly to primary runways except that it needs only to be adequate for those aero planes which require to use that secondary runway in addition to the other runway or runways in order to obtain a usability factor of at least 95 per cent. Recommended Runway Length The analysis presented earlier in Derivative Stage Length Analysis (DSLA), indicates that a runway length of 6,000 feet is the absolute minimum length considered at FLL to be usable by 80 percent of the projected peak hour fleet for departures. A maximum primary runway length of 8,000 feet will accommodate at least 90 percent of the design day aircraft departures at 90 percent maximum payload. A secondary runway at FLL should be as close to 8,000 feet in length, plus grade adjustments, as practicable, but not less than 6,000 feet. An analysis was conducted to determine the runway length requirements for passenger air carrier, commuter, and cargo aircraft operating at Dayton International Airport (DAY). Based on 100% maximum takeoff weights (MTOW) of the existing and future aircraft fleet mix through year 2020, the following runway lengths are justified at DAY. Justified Runway Lengths Runway Justified Runway Length (ft.) 6R-24L 13,900 primary runway 6L-24R 13,900 primary runway 18-36 11,120 secondary runway

44. What is meant by runway saturation? Ans: The runway saturation means that how much arrival and departure of aircraft can accommodate with respect to available runway capacity whether control tower is available or not. Existing airports without a control tower have very small runway saturation capacities (4-5 arrivals



per hour). The saturation capacity of an airport with HVO (ADS-B) technology depends on the safety buffers allowed and the delivery accuracy of pilots/AMM system. The variation in technical parameters such as γ and δ affects the results of saturation capacity. The saturation capacity of an airport depends on the runway configuration used. The saturation capacity during VMC conditions is higher than during IMC conditions (due to shorter separation minima). The variation in technical parameters such as γ and δ affects the results of saturation capacity. 45. Define instrument runway. Ans: Instrument Runway: Runway meant for simultaneous approaches to parallel or near-parallel runways where radar separation minima between aircraft on adjacent extended runway centre lines are not prescribed is called instrument runway. Explanation for understanding Instrument Runway: One of the following types of runways intended for the operation of aircraft using instrument approach procedures: a) Non-precision approach runway. An instrument runway served by visual aids and a non-visual aid providing at least directional guidance adequate for a straight-in approach. b) Precision approach runway, category I. An instrument runway served by ILS and/or MLS and visual aids intended for operations with a decision height not lower than 60 m (200 ft) and either a visibility not less than 800 m or a runway visual range not less than 550 m. c) Precision approach runway, category II. An instrument runway served by ILS and/or MLS and visual aids intended for operations with a decision height lower than 60 m (200 ft) but not lower than 30 m (100 ft) and a runway visual range not less than 350 m. d) Precision approach runway, category III. An instrument runway served by ILS and/or MLS to and along the surface of the runway and: A C intended for operations with a decision height lower than 30 m (100 ft), or no decision height and a runway visual range not less than 200 m. B C intended for operations with a decision height lower than 15 m (50 ft), or no decision height and a runway visual range less than 200 m but not less than 50 m. C C intended for operations with no decision height and no runway visual range limitations. Note. C Visual aids need not necessarily be matched to the scale of non-visual aids provided. The criterion for the selection of visual aids is the conditions in which operations are intended to be conducted.



UNIT V 46. What is meant by landing direction indicator? Ans: Landing Direction Indicator: a device to indicate visually the direction currently designated for landing and for take-off.

47. Distinguish between ICAO system and Calvert system? Ans: S.No. ICAO system Calvert System

1 One of the two basic categories of approach lighting system

One of the two basic categories of approach lighting system

2 In most aspects US standards for approach lighting system are virtually identical to ICAO standards which is approved by FAA

Used UK, Europe and other parts of the world particularly in Commonwealth countries

3

There are two basic categories of ALS which are high intensity and medium intensity system. They are composed barrettes of five white lights along the extended runway centerline.

This system is distinguished by six transverse lines of lights variable length at right angles to the axis of approach

4

The effect of the bright or medium intensity sequenced flashes gives the appearance of a fast moving ball of light travelling toward the runway.

The length of the transverse bars diminishes as the pilot approaches the threshold.

48. What is aerodrome beacon? Ans: Airport beacons help a pilot to identify an airport at night. The beacons are operated from dusk till dawn. Sometimes they are turned on if the ceiling is less than 1,000 feet and/or the ground visibility is less than 3 statute miles (VFR minimums). However, there is no requirement for this, so a pilot has the responsibility of determining if the weather meets VFR requirements. The beacon has a vertical light distribution to make it most effective from 1–10° above the horizon, although it can be seen well above or below this spread. The beacon may be an Omni directional capacitor-discharge device, or it may rotate at a constant speed, which produces the visual effect of flashes at regular intervals. The combination of light colors from an airport beacon indicates the type of airport. Some of the most common beacons are: • Flashing white and green for civilian land airports; • Flashing white and yellow for a water airport; • Flashing white, yellow, and green for a heliport; and • Two quick white flashes alternating with a green flash identifying a military airport.



49. Explain why Aerodrome beacon lights are required? Ans: An aerodrome beacon or rotating beacon is a beacon installed at an airport or aerodrome to indicate its location to aircraft pilots at night. An aerodrome beacon is mounted on top of a towering structure, often a control tower, above other buildings of the airport. It produces flashes not unlike that of a lighthouse. Airport and heliport beacons are designed in such a way to make them most effective from one to ten degrees above the horizon; however, they can be seen well above and below this peak spread. The beacon may be an omni directional flashing xenon strobe, or it may rotate at a constant speed which produces the visual effect of flashes at regular intervals. Flashes may be of just a single color, or of two alternating colors. 50. Draw the lighting system of the runway. Ans:

51. Explain the emergency marking denoted by runway lighting. Ans: At an aerodrome provided with runway lighting and without a secondary power supply, sufficient emergency lights should be conveniently available for installation on at least the primary runway in the event of failure of the normal lighting system. When installed on a runway the emergency lights should, as a minimum, conform to the configuration required for a non‐instrument runway.



52. Give the various marking shown in the runway. Ans: The following are the various marking on the runway: Runway designation marking, Runway centre line marking, Threshold marking, Transverse stripe, Arrows marking, Aiming point marking, Touchdown zone marking, Runway side stripe markings, Taxiway centre line marking, Taxiway intersection marking, Runway turn pad marking, Runway holding position marking, Intermediate holding position marking, VOR aerodrome check point marking, Apron safety lines, Information marking.

53. What are the six groups of the airport markings? Ans: There are six groups of airport markings: Runway markings, Taxiway markings, VOR receiver checkpoint markings, Vehicle roadway marking, Non movement area boundary markings and Information marking The six types of marking signs are: Mandatory Instruction Signs, Location Signs, Direction Signs, Destination Signs, Information Signs, and Runway Distance Remaining Signs 54. What is the visual aid for wind direction? Ans: The visual aid for wind direction indicator can be a wind cone, wind sock, tetrahedron, or wind tee. These are usually located in a central location near the runway and may be placed in the center of a segmented circle, which identifies the traffic pattern direction, if it is other than the standard left-hand pattern. The wind sock is a good source of information since it not only indicates wind direction, but allows the pilot to estimate the wind velocity and gusts or factor. The wind sock extends out straighter in strong winds and tends to move back and forth when the wind is gusty. Wind tees and tetrahedrons can swing freely, and align themselves with the wind direction. The wind tee and tetrahedron can also be manually set to align with the runway in use; therefore, a pilot should also look at the wind sock, if available.

55. Explain few emergencies procedure. Ans:

1. A situation in which the response of all agencies involved in the aerodrome emergency plan will be activated. A full emergency will be declared when an aircraft approaching the airport is known or suspected to be in such trouble that there is danger of an accident.

2. LAND RESCUE UNIT equipped to undertake a search for an aircraft within the region of its responsibility

3. RADAR/ADS-B INFORMATION SERVICE (RIS) on request service provided to assist pilots of pilots VFR flights within ATS surveillance system coverage in class E and G airspace to avoid other aircraft or to assist in navigation

4. RESCUE CORRDINATION CENTER for promoting efficient organization of search and rescue service within the region of responsibility.

56. Explain Alerting Service. Ans: When so required by the appropriate ATS authority to facilitate the provision of alerting and search and rescue services, an aircraft, prior to and when operating within or into designated areas or along designated routes, shall comply with the provisions detailed in rules, concerning the submission, completion, changing and closing of a flight plan.



When alerting service is required in respect of a flight operated through more than one FIR or control area, and when the position of the aircraft is in doubt, responsibility for coordinating such service shall rest with the ATS unit of the FIR or control area

57. What is altimeter setting? Ans: Altimeter Setting: a pressure datum which when set on the subscale of a sensitive altimeter causes the altimeter to indicate vertical displacement from that datum. A pressure type altimeter calibrated in accordance with Standard Atmosphere may be used to indicate altitude, height or flight levels as follows:

1. When set to QNH or area QNH it will indicate altitude; 2. When set to Standard Pressure (1013.2 hPa) it may be used to indicate flight levels.

58. Explain QFE setting. Ans: QFE, which refers to the altimeter setting that, will cause the altimeter to read the height above a specific aerodrome or ground level, and therefore read zero on landing. While using QFE is convenient while flying in the traffic circuit of an airfield. When set to ‘0000’ it may be used to indicate height above aerodrome or ground level.

59. Explain QNH setting. Ans: QNH is defined as, "barometric pressure adjusted to sea level." It is a pressure setting used by pilots, air traffic control (ATC), and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to read altitude above mean sea level within a certain defined region.

60. Define QNH & QFE. Ans:



QNH is defined as, "barometric pressure adjusted to sea level." It is a pressure setting used by pilots, air traffic control (ATC), and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to read Altitude above mean sea level within a certain defined region. QFE, which refers to the altimeter setting that, will cause the altimeter to read the height above a specific aerodrome or ground level, and therefore read zero on landing. While using QFE is convenient while flying in the traffic circuit of an airfield. QFE and QNH are arbitrary Q codes rather than abbreviations, but the mnemonics "Nautical Height" (for QNH) and "Field Elevation" (for QFE) are often used by pilots to distinguish them. 61. Give the various altimeters setting followed in India. Ans:

1. When cruising at or above Transition Level (TRL), use the Standard Altimeter setting 1013.25 hPa or 29.92 In Hg (Red part on the drawing).

2. During descent through Transition Level (TL), select QNH. 3. Cruising at or below Transition Altitude (TA), use QNH (Blue part on

the drawing). 4. When climbing through the Transition Altitude (TA), the Standard

Altimeter is set to 1013.25 hPa or 29.92 In Hg.

NB: for understanding

1. The transition altitude (TA) is the altitude AT OR BELOW which pilots have to use the QNH setting. That means you are flying at ALTITUDES

2. The TRansition Level (TRL) is the FIRST FLIGHT LEVEL that may be used ABOVE TA. From here, pilots have to use the STANDARD altimeter setting 1013 hPa or 29.92 inHg.

3. A Flight Level (FL) is the vertical distance of an aircraft above the ISOBARIC SURFACE of 1013,25 hPa (hectopascal) or 29.92 in Hg (inches of Mercury).

4. An "ISOBARIC SURFACE" is the "invisible landscape" that connects all points with the same atmospheric pressure. In aviation, 1013,25 hPa (hectopascal) / 29.92 in Hg (inches of Mercury) are referred to as the STANDARD altimeter setting.

62. Define VASI & PAPI. Ans: The visual approach slope indicator (VASI) is a system of lights on the side of an airport runway threshold that provides visual descent guidance information during the approach to a runway. These lights may be visible from up to eight kilometers (five miles) during the day and up to 32 kilometers (20 miles) or more at night.



Precision approach path Indicator (PAPI) is a visual aid that provides guidance information to help a pilot acquire and maintain the correct approach (in the vertical plane) to an aerodrome or an airport.

63. What is VAPI? Ans: A visual approach slope indicator (VASI or VAPI) system shall be provided to serve the approach to a runway where one or more of the following conditions exits:

- The runway is not served by an electronic glide path and the runway is used by turbojet or other aircraft with similar approach guidance requirements;

- The pilot of any type of aircraft may have difficulty in judging the approach due to:

1. Inadequate visual guidance such as is experienced during an approach over water, 2. or featureless terrain by day or in the absence of sufficient extraneous lights in the

approach area by night, or 3. Misleading information such as is produced by deceptive surrounding terrain or

runway slopes; Or

Visual approach slope indicators (VASI or VAPI) consist of one set of lights set up some seven meters (twenty feet) from the start of the runway. Each light is designed so that the light appears as either white or red, depending on the angle at which the lights are viewed. When the pilot is approaching the lights at the proper angle, meaning the pilot is on the glide slope, the first set of lights appears white and the second set appears red. When both sets appear white, the pilot is flying too high, and when both appear red he or she is flying too low. This is the most common type of visual approach slope indicator system.

64. What is meant by PAPI? Ans: The standard visual approach slope indicator systems shall consist of PAPI and APAPI systems conforming to the specifications. Precision Approach Path Indicator (PAPI) consists of four sets of lights in a line perpendicular to the runway, usually mounted to the left side of the runway. These have a similar purpose to basic visual approach slope indicators, but the additional lights serve to show the pilot how far off the glide slope the aircraft is. When the lights show White-White-Red-Red the aircraft is on the correct glide slope for landing, usually 3.0°. Three red lights (white–red–red–red) indicate that the aircraft is slightly below glide slope (2.8°), while four red lights (Red-Red-Red-Red) indicate that the aircraft is significantly below glide slope (<2.5°). Conversely, three white lights (white–white–white–red) indicate that the aircraft is slightly above glide slope (3.2°), and four white lights (White-White-White-White) indicated that the aircraft is significantly above glide slope (>3.5°). 65. Define terminal aids? Ans: Terminal aids: an airfield equipped with control tower and hangars as well as accommodations for passengers and cargo. An airport (terminal) is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport. An airport consists of at least one surface such as a runway for a plane to take off and land, a helipad, or water for takeoffs and landings, and often includes buildings such as control towers, hangars and terminal buildings.



PART A Nov/Dec 2011 1. What are the objectives of ATS? Ans:

REFER QUES No.08 in Part A 2. What is altimeter setting? Ans:

REFER QUES No.57 in Part A 3. Why should one assign the minimum cruising level? Ans: Cruising level is a level maintained during a significant portion of a flight. Also,Cruising altitude is an altitude or flight level maintained during en-route level flight. This is a constant altitude. Cruising levels which specifies assignment of vertical separation minimum of 1000 ft between flight level (FL) 290 and FL 410 inclusive based on direction of flight. Traffic permitting, ATC will assign the flight planned level in accordance with the table of semi-circular system of Cruising Levels. Cruising levels below the minimum specified in ENR 3.1 will not be assigned. These specific instructions take into account the predominant traffic flows within and between the regions, as well as the unique characteristics of each State’s cruising level procedures With only 300 metres (1 000 ft) separating the respective cruising levels, every effort must be made to standardize and simplify procedures. This reduces complexity for air traffic controllers and for flight crews. 4. Explain what is a flight plan. Ans: Flight plans are documents filed by pilots or a Flight Dispatcher with the local Civil Aviation Authority (e.g. DGCA in INDIA) prior to departure. Flight plans are documents filed by pilots or a Flight Dispatcher with the local Civil Aviation Authority prior to departure. Flight plan format is specified in the ICAO Doc 4444. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), the pilot's information, number of people on board and information about the aircraft itself. In most countries, flight plans are required for flights under IFR, but may be optional for flying VFR unless crossing international borders. 5. What is the basic principle of Radar? Ans:

REFER QUES No.30 in Part A 6. How PAR is used to control air traffic? Ans:

REFER QUES No.31 in Part A 7. What is the length of Primary Runway? Ans:

REFER QUES No.43 in Part A 8. Why there should be obstacle restrictions? Ans:

REFER QUES No.42 in Part A 9. Explain why Aerodrome beacon lights are required? Ans:

REFER QUES No.49 in Part A 10. What is the visual aid for wind direction? Ans:

REFER QUES No.55 in Part A



PART A Apr/May 2010 1. Describe the two basic types of flight rules. Ans:

REFER QUES No.09 in Part A 2. What are the tree components of ATC network? Ans:

REFER QUES No.10 in Part A 3. Define RNAV Ans:

REFER QUES No.25 in Part A 4. Mention different categories of Airports. Ans:

REFER QUES No.12 in Part A 5. Distinguish between ICAO system and Calvert system. Ans:

REFER QUES No.47 in Part A 6. What is meant by basic runway length? Describe three cases to be considered. Ans:

REFER QUES No.39 in Part A 7. Define Aerodrome. Ans:

REFER QUES No.03 in Part A 8. What is meant by runway saturation? Ans:

REFER QUES No.44 in Part A 9. What are the six groups of the airport markings? Ans:

REFER QUES No.53 in Part A 10. Define terminal aids Ans:

REFER QUES No.65 in Part A



PART-B 1. Describe the classification of ATS Air space. Ans: Controlled air space: an air space of defined dimensions within which air traffic control service is provided to aerodrome traffic with airspace classification. Controlled air space which covers ATS airspaces classes A, B, C, D and E. Un-Controlled air space: an airspace where an Air Traffic Control (ATC) service is not deemed necessary or cannot be provided for practical reasons. According to the airspace classes set by ICAO both class F and class G airspace are uncontrolled. It is the opposite of controlled airspace. ATC does not exercise any executive authority in uncontrolled airspace, but may provide basic information services to aircraft in radio contact. Flight in uncontrolled airspace will typically be under VFR. Aircraft operating under IFR should not expect separation from other traffic: however in certain uncontrolled airspace this might be provided on an 'as far as is practical' advisory basis. Classification of ATS airspaces: Since the number of aircraft flying is relatively high, with the number of aircraft flying over the worldwide today, proper airspace usage is critical for flight safety and efficient service to pilots and the flying public. To assist in this goal, the airspace is divided into five classifications. Class A Airspace: Class A Airspace is the airspace from FL 180 or 18,000 feet to FL 600 or 60,000. All pilots flying in Class A airspace shall file an Instrument Flight Rules (IFR) flight plan and receive an appropriate air traffic control (ATC) clearance. When climbing through 18,000 feet, the pilot will change the altimeter setting from the local altimeter (30.01 for example) to 29.92. This ensures all aircraft flying in class A airspace have the same altimeter setting and will have proper altitude separation. Class B Airspace Class B Airspace is generally the airspace from the surface to 10,000 feet. Class B airspace is individually designed to meet the needs of the particular airport and consists of a surface area and two more layers. Most Class B airspace resembles an upside down wedding cake. Pilots must contact air traffic control to receive an air traffic control clearance to enter Class B airspace. Once a pilot receives an air traffic control clearance, they receive separation services from other aircraft within the airspace. Class C Airspace Class C Airspace is the airspace from the surface to 4,000 feet above the airport elevation. Class C airspace will only be found at airports that have an operational control tower, are serviced by a radar approach control, and that have a certain number of IFR operations. Although Class C airspace is individually tailored to meet the needs of the airport, the airspace usually consists of a surface area with a 5 nautical mile (NM) radius, an outer circle with a 10 NM radius that extends from 1,200 feet to 4,000 feet above the airport elevation and an outer area. Pilots must establish and maintain two-way radio communications with the ATC facility providing air traffic control services prior to entering airspace. Pilots of visual flight rules (VFR) aircraft are separated from pilots of instrument flight rules (IFR) aircraft only. Class D Airspace The fourth airspace is Class D Airspace which is generally that airspace from the surface to 2,500 feet above the airport elevation. Class D airspace only surrounds airports that have an operational control tower. Class D airspace is also tailored to meet the needs of the airport. Pilots are required to establish and maintain two-way radio communications with the ATC facility providing air traffic control services prior to entering the airspace. No separation services will be provided to pilots of VFR (Visual Flight Rules) aircraft. Pilots operating under VFR must still use "see-and-avoid" for aircraft separation. Airports without operating control towers are uncontrolled



airfields. Here pilots are responsible for their own separation and takeoff and landings. Uncontrolled airports use a "UNICOM" frequency that pilots will transmit their intentions to other aircraft using the airport. Class E Airspace The fifth airspace to discuss is Class E Airspace which is generally that airspace that is not Class A, B, C, or D. Class E airspace extends upward from either the surface or a designated altitude to the overlying or adjacent controlled airspace. If an aircraft is flying on a Federal airway below 18,000 feet, it is in Class E airspace. Class E airspace is also the airspace used by aircraft transiting to and from the terminal or en route environment normally beginning at 14,500 feet to 18,000 feet. Class E airspace ensures IFR aircraft remain in controlled airspace when approaching aircraft without Class D airspace. Class G Airspace Class G Airspace is uncontrolled airspace. IFR aircraft will not operate in Class G airspace. VFR aircraft can operate in Class G airspace. NB: the following are additional incase the ques has been asked to for classification of airspace in India ATS airspaces in India are classified and designated in accordance with following: Class D: IFR and VFR flights are permitted and all flights are provided with air traffic control service, IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights. VFR flights receive traffic information in respect of all other flights. Airspaces in terminal areas, control areas, control zones and aerodrome traffic zones have been classified and designated as class D airspace. Class E: IFR and VFR flights are permitted; IFR flights are provided with air traffic control service and are separated from other IFR flights. IFR flights receive traffic information in respect of VFR flights, VFR flights receive traffic information in respect of all other flights, as far as is practical. Class E is not be used for control zones. Airspaces in designated ATS routes outside terminal areas, control areas and control zones, where air traffic control service is provided, have been classified and designated as class E airspace. Class F: IFR and VFR flights are permitted. All IFR flights receive an air traffic advisory service and all flights receive flight information service, if requested. Airspaces in designated ATS route segments outside terminal areas, control areas and control zones, where air traffic advisory service is provided, have been classified and designated as class F airspace. Class G: IFR and VFR flights are permitted and receive flight information service if requested. Airspaces other than those in Class D, E and F have been classified and designated as class G airspace.

2. Describe the various kinds of separation with provision of Area Control Service Ans: Area Control Service: General Provisions for the Separation of Controlled Traffic

1.1 Vertical or horizontal separation shall be provided: a) Between all flights in Class A and B airspaces: b) Between IFR flights in Class C, D and E airspaces: c) Between IFR flights and VFR flights in Class C airspace: d) Between special IFR flights and special VFR flights and e) Between special VFR flights when so prescribed by the appropriate ATS

authority: Except for the case under a), b) and c) above during hours of daylight when flights have cleared to climb or descend subject to maintaining own separation and remaining in visual meteorological conditions.



1.2 No clearance shall be given to execute any maneuver that would reduce the spacing between two aircraft to less than the separation minimum applicable in the circumstances.

1.3 Larger separations than the specified minima should be applied whenever wake turbulence or exceptional circumstances such as unlawful interference call for extra precautions. This should be done with due regard to all relevant factors so as to avoid impending the flow of air traffic by the applications of excessive separations.

1.4 Where the type of separation or minimum used to separate two aircraft cannot be maintained, action shall be taken to ensure that another type of separation or another minimum exists or is established prior to the time when the previously used separation would be insufficient.

VERTICAL SEPARATION: Vertical separation application:

2.1 Vertical is obtained by requiring aircraft using prescribed altimeter setting procedures to operate at different levels expressed in terms of flight levels or altitudes.

Vertical Separation minimum: 3.1 the vertical separation minimum (VSM) shall be:

a) within designated airspace subject to regional air navigation agreement: a nominal 300m (1000ft) below FL 410 or a higher level where so prescribed for use under specified condition and a nominal 600m (2000ft) at or above this level: and

b) within other airspace: a nominal 300m (1000ft) below FL 290 and a nominal 600m (2000ft) at or above this level

Vertical separation during ascent or descent 4.1 Pilots in direct communication with each other may, with their concurrence, be cleared to maintain a specified vertical separation between their aircraft during ascent or descent. Horizontal Separation

a) other minima for use in circumstances not prescribed; or b) additional conditions to those prescribed for the use of a given minimum;

Lateral Separation Lateral Separation Application 5.1 Lateral separation shall be applied so that the distance between those portions of the intended routes for which the aircraft are to be laterally separated is never less than an established distance to account for navigational inaccuracies plus a specified buffer. This buffer shall be determined by the appropriate authority and included in the lateral separation minima as an integral part thereof. 5.2 Lateral separation of the aircraft at the same level is obtained by requiring operation on different routes or in different geographical locations as determined by visual observation, by use of navigation aids or by use of area navigation equipment. Lateral Separation criteria and minima



5.3 Means by which lateral separation may be achieved include the following: a) Geographical separation i.e., separation positively indicated by position reports over different geographical locations as determined visually or by reference to a navigation aid (fig III-1) b) Track separation between aircraft using the same navigation aid or method. By requiring aircraft to fly on specified tracks which are separated by a minimum amount appropriate to the navigation aid or method employed as follows: 1. VOR: at least 15 degrees and at a distance of 28 Km (15 NM) or more from the facility. 2. NDB: at least 30 degrees and at a distance of 28 Km (15 NM) or more from the facility. 3. DR: tracks diverging by at least 45 degrees and at a distance of 28 Km (15 NM) or more from the point of intersection of the tracks. This point being determined either visually or by reference to a navigation aid. When aircraft are operating on tracks which are separated by considerably more than the foregoing minimum figures, states may reduce the distance at which lateral separation is achieved.

5.4 Track separation between aircraft transitioning into airspace over the high seas. By requiring aircraft to fly on specified tracks which are separated by at least degrees and at a distance of 28 Km (15 NM) or more from the same VOR provided that: a) The aircraft tracks continue to diverge by at least 15 degrees until the appropriate lateral separation minimum is established in airspace over the high seas and b) It is possible to ensure, by means approved by the appropriate ATS authority, that the aircraft have the navigation capability necessary to ensure accurate track guidance. 5.5 Track separation between aircraft using different navigation aids or methods. Track between aircraft using different navigation aids and area navigation (RNAV) equipment may be achieved by requiring aircraft to fly on specified tracks which are determined by taking account of navigational accuracy of the navigations aid and RNAV equipment used by each aircraft and where the protection areas thus established for each track do not overlap. Longitudinal Separation Longitudinal separation application: 6.1 Longitudinal separation shall be applied so that the spacing between the estimated positions of the aircraft being separated is never less than a prescribed minimum. Longitudinal separation between aircraft following the same or diverging tracks may be maintained by application of the Mach number technique, when so prescribed on the basis of regional air navigation agreement. 6.2 Longitudinal separation shall be established by requiring aircraft to depart at a specified time, to lose time to arrive over a geographical location at a specified time, or to hold over a geographical location until a specified time. 6.3 Longitudinal separation between supersonic aircraft during the transonic acceleration and supersonic phases of flight should normally be established by appropriate timing of the start of transonic acceleration rather than by the imposition of speed restrictions in supersonic flight. 6.4 For the purpose of application of longitudinal separation, the terms same track, reciprocal tracks and crossing tracks shall have the following meanings:

a) Same track: same direction tracks and intersecting tracks or portions thereof, the angular difference of which is less than 45 degrees or more than 315 degrees, and whose protection areas overlap. b) Reciprocal tracks: Opposite tracks and intersecting tracks or portions thereof, the angular difference of which is more than 135 degrees but less than 225 degrees and whose protection areas overlap.



c) Crossing tracks: intersecting tracks or portions thereof other than those specified in a) and b) above.

Longitudinal separation minima based on time: 6.5 Aircraft at the same cruising level: Aircraft flying on the same track:

a) 15minutes or b) 10 minutes, if navigation aids permit frequent determination of position and

speed or c) 5 minutes in the following cases, provided that in each case the preceding

aircraft is maintaining a true airspeed of 37 Km/h (20kt) or more faster than the succeeding aircraft: i) Between aircraft that have departed from the same aerodrome ii) Between en-route aircraft that have reported over the same exact reporting

point.

3. Explain the conditions for operating VFR/SPECIAL VFR flights Ans: Visual flight rules (VFR Flights) Visual flight rules (VFR) are a set of regulations which allow a pilot to operate an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.

- Specifically, the weather must be better than Basic VFR Weather Minimums, as specified in the rules of the relevant aviation authority.

- If the weather is worse than VFR minimums, pilots are required to use Instrument Flight Rules.

- Meteorological conditions that meet the minimum requirements for VFR flight are termed visual meteorological conditions (VMC).

- If they are not met, the conditions are considered instrument meteorological conditions (IMC), and a flight may only operate under IFR.

- VFR rules require a pilot to be able to see outside the cockpit, to control the aircraft's attitude, navigate, and avoid obstacles and other aircraft.

- A VFR flight is "conducted in accordance with the visual flight rules - An aircraft operated in accordance with the visual flight rules which wishes to

change t g o compliance with the instrument flight rules shall� - Communicate the necessary changes to be effected to its current flight plan or - Submit a flight plan to the appropriate air traffic services unit and obtain a clearance prior to proceeding IFR when in controlled airspace.

Except when operating as special VFR flight, VFR flights shall be conducted so that the aircraft is flown in conditions of visibility and distance from clouds equal to or greater than those specified visual meteorological conditions visibility and distance from cloud minima given below:

Airspace Class

Class D & E Class F & G

Minimum Altitude /

Height

Above 900 M AMSL (3000 ft AMSL) Or Above 900 M AMSL (1000 ft AGL) whichever is higher

At and below 900 M AMSL (3000 ft AMSL) Or Above 900 M AMSL (1000 ft AGL) whichever is higher

Distance from cloud

1500 M horizontally and 300 M (1000 ft AMSL) Clear of cloud and in sight of the surface

Flight visibility

8 KM – at and above 3050M AMSL (10000 ft AMSL) 5 KM - below 3050M AMSL (10000 ft AMSL)

5 KM**



* When the height of the transition altitude is lower than 3050M AMSL (10000 ft AMSL) FL 100 should be used in lieu of 10000 ft. ** Helicopters may be permitted to operate in 1500M flight visibility, or higher, if maneuvered at a speed that will give adequate opportunity to observe other traffic or any obstacle in time to avoid collision. VFR Rules

- Except when a clearance is obtained from an air traffic control unit, VFR flights shall not take‐off or land at an aerodrome within a control zone or enter the aerodrome traffic zone or traffic pattern:

- When the ceiling is less than 450M (1550 Ft) or - When the ground visibility is less than 5KM. - VFR flights shall not be operated between sunset and sunrise, except when exempted by air traffic control for local flights and such training flights of flying club aircraft as may be cleared by air traffic control. - VFR flights cannot be operated‐ - Above FL50 - At transonic and supersonic speeds - More than 100 NM seaward from the shoreline within controlled airspace. - Expect when necessary for take‐off or landing or except by permission from appropriate authority, a VFR flight shall not be flown‐ - Over congested area of city, town or settlements or over an open‐air assembly of persons at a height less than 300M above the highest obstacle within a radius of 600M from the aircraft.

Special VFR Special VFR conditions - meteorological conditions that are less than those required for basic VFR flight in Class B, C, D, or E surface areas and in which some aircraft are permitted flight under visual flight rules. Special VFR operations - aircraft operating in accordance with clearances within Class B, C, D, and E surface areas in weather conditions less than the basic VFR weather minima. Such operations must be requested by the pilot and approved by ATC. Special VFR occurs when basic VFR cannot be maintained, and the pilot requests an SVFR departure or arrival. a. SVFR operations in weather conditions less than basic VFR minima are authorized:

1. At any location not prohibited by 14 CFR Part 91, Appendix D. 14 CFR Part 91 does not prohibit SVFR helicopter operations, however, so those can be authorized anywhere. 2. Only within the lateral boundaries of Class B, Class C, Class D, or Class E surface areas, below 10,000 feet MSL. 3. Only when requested by the pilot. A controller must never initiate a SVFR operation himself. 4. On the basis of weather conditions reported at the airport of intended landing/departure. 5. When weather conditions are not reported at the airport of intended landing/departure and the pilot advises that VFR cannot be maintained and requests SVFR.

4. ( i)Describe the contents of FLIGHT PLAN Ans:

Flight plan: Specified information provided to air traffic services units, relative to an intended flight or portion of a flight of an aircraft.



Flight plans are documents filed by pilots or a Flight Dispatcher with the local Civil Aviation Authority prior to departure. Flight plan format is specified in the ICAO Doc 4444. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), the pilot's information, number of people on board and information about the aircraft itself. In most countries, flight plans are required for flights under IFR, but may be optional for flying VFR unless crossing international borders. Flight plans are highly recommended, especially when flying over inhospitable areas, such as water, as they provide a way of alerting rescuers if the flight is overdue. In the United States and Canada, when an aircraft is crossing the Air Defense Identification Zone (ADIZ), either an IFR or a special type of VFR flight plan called a DVFR flight plan must be filed (the "D" is for Defense). For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required, or for use by air traffic control when flying in a "Special Flight Rules Area". Contents of a Flight Plan The ICAO FPL form shall be used for the purpose of completing a flight plan prior to departure or, in case the flight plan is submitted by telephone or tele-fax, the sequence of items in the flight plan form shall be strictly followed. The following information shall be included in the flight plan:

• Aircraft identification • Flight rules and type of the flight • Number of aircraft, type of aircraft and wake turbulence category • Equipment • Departure aerodrome • Estimated off-block time • Cruising speed • Level • Route • Destination aerodrome and total estimated elapsed time • Alternate aerodrome(s) • Endurance • Persons on board • Survival equipment • Pilot in command • Other information

If a flight is to cross a Finish state border, details of the entire flight to the destination aerodrome shall be submitted in the flight plan. Aircraft Identification Maximum : 7 characters [The registration marking of the aircraft (ALK505)] Flight Rules (1 character) :The flight rules which the pilot intends to comply I = if IFR first V = if VFR first Y = if IFR first * Z = if VFR first * - specify in item 15 the point or points at where a change of flight rules is planned. Type of Flight (1 character) : S = scheduled services N = non-scheduled Air Transport Operations



G = General aviation M = Military X = Other than any of the defined categories above Number and Type of aircraft: Number of aircraft (1 or 2 characters.) Insert number of aircraft, but only if more than one Type of aircraft (2 to 4 characters) : The designator as specified by ICAO, Wake Turbulence Category (1 character) : H = Heavy, to indicate an aircraft type with a MTOW of 136000 Kg (300000lb) or more. M = Medium, to indicate a MTOW less than 136000 Kg but more than 7000 Kg (15500lb) L = Light, to indicate a MTOW of 7000 Kg or less. Equipment: Radio Communication, Navigation and Approach Aid equipment. Preceding the oblique stroke, insert one letter as follows: N = No equipment for the route to be flown is carried, or the equipment is unserviceable. S = Standard COM/NAV equipment for the route to be flown is carried and serviceable. Following letters indicate the COM/NAV equipment available and serviceable: A - LORAN A C - LORAN C D - DME E - DECCA F - ADF H - HF RTF I - Inertial Navigation L - ILS M - Omega O - VOR P - Doppler R - RNAV route equipment T - TACAN U - UHF RTF V - VHF RTF Z - Other equipment; specify in item 18, preceded by COM/ or NAV/ then, following the oblique stroke, insert one of the following to describe the serviceable SSR equipment carried: N - Nil A - Transponder - mode A - 4096 codes C - Transponder - mode A - 4096 codes and mode C X - Transponder - mode S - without pressure altitude and without aircraft identification transmission P - Transponder - mode S - with pressure altitude but without aircraft identification transmission I - Transponder - mode S - without pressure altitude but with aircraft identification transmission X - Transponder - mode S - with both pressure altitude and aircraft identification transmission Departure Aerodrome (4 characters) : Location Indicator of the departure aerodrome(Every airfield has a Location Indicator like Bandaranaike International Airport is VCBI)., or if no location indicator assigned, insert ZZZZ and specify in item 18, the name of the aerodrome, preceded by DEP/ VCBI V: The region. C: Sri Lanka - The country within the region. BI: Bandaranaike International - the facility within the country.



VCCA Anuradapura VCCB Batticaloa Time (4 characters): The estimated departure time Cruising Speed (maximum 5 characters) : True Airspeed for the first or whole portion of the flight, in terms of:

- Kilometres per hour, expressed as K followed by 4 figures (e.g. K0350) - Knots, expressed as N, followed by 4 figures (e.g. N0220) - Mach number, when so prescribed by the appropriate ATS authority to the

nearest hundredths of unit mach, expressed as M followed by 4 figures (e.g. M082)

Level [Cruising] (maximum 5 characters) : planned cruising level for the first or the whole cruising portion of the route to be flown, in terms of:

- Flight level expressed as F followed by 3 figures (e.g. F085, F330) - Altitude in hundreds of feet expressed as A followed by 3 figures, (e.g. A045,

A100) - Standard Metric level in tens of meters expressed as S followed by 4 figures

(e.g. S1130) - Altitude in tens of meters expressed as M followed by 4 figures (e.g. M0840) - or, for VFR flights where the flight is not planned to be flown at a specific

cruising level, the letters VFR. - When so prescribed by the appropriate ATS authorities.

Route: Including changes of speed, level and/or flight rules. (note that this is an abbreviated instruction) Flight along designated ATS routes: Designator of the first route, or the letters DCT followed by the point of joining the route then insert each point at which a change of route, speed, level or flight rules is planned, followed by the designator of the next route segment. Flight outside designated routes: points not normally more than 30 minutes flying time, or 200 nm apart, including each point where a change of speed, level, track or flight rules is planned. Destination Aerodrome (4 characters) : Location indicator of the destination aerodrome EET (4 characters) : Total estimated elapsed time: Alternate aerodromes: Location indicator of not more than two aerodromes. Other information: 0 (zero) if no other information, or, any other necessary information in the preferred sequence shown below.

- RFP/ EET/ RIF/ REG/ SEL/ OPR/ STS/ TYP/ PER/ COM/ NAV/ DEP/ DEST/ ALTN/ RMK/

Supplementary Information: This information is not filed with the plan, but is kept at the unit where the plan was filed. In case of emergency the supplementary information will be transmitted to the appropriate rescue agencies. Endurance: After -E/ a 4 figure group giving the fuel endurance in hours and minutes Persons on Board: After -P/ insert the total number of persons (passengers and crew) on board, when required by the appropriate ATS authority. Emergency and Survival Equipment: -R/(radio) - cross out U if UHF on frequency 243.0MHz is not carried - cross out V if VHF on frequency 121.5 MHz is not carried - cross out E if emergency location beacon - aircraft (ELBA) is not available -S/ (Survival Equipment) - cross out all indicators if survival equipment is not carried - cross out P if polar survival equipment is not carried



- cross out D if desert survival equipment is not carried - cross out M if maritime survival equipment is not carried. Note: this refers to equipment in addition to the lifejackets listed in the following section - cross out J if Jungle survival equipment is not carried - J/ Jackets - cross out all indicators if lifejackets are not carried - cross out L if lifejackets are not fitted with lights - cross out F if jackets are not equipped with fluorescent - cross out U or V or both as in R/ above to indicate radio capability of jackets, if any. -D/ (dinghies) (number) cross out indicators D and C if no dinghies are carried, or insert number of dinghies carried and; - (CAPACITY) insert total capacity, in persons, of all dinghies carried, and - (COVER) cross out indicator C if dinghies are not covered and - (COLOUR) insert colour of dinghies if carried. A/ (AIRCRAFT COLOUR AND MARKINGS) insert colour of aircraft and significant markings N/ (REMARKS) cross out indicator N if no remarks, or indicate any other survival equipment carried and any other remarks regarding survival equipment. C/ (PILOT) insert name of pilot in command Example for understanding:



ii) Describe the scope and provision of ATS Ans: The objectives or the scope of the Air Traffic Services shall be to: a) Prevent collisions between aircraft. b) Prevent collisions between aircraft on the maneuvering area and obstructions on that area. c) Expedite and maintain an orderly flow of air traffic. d) Provide advice and information useful for the safe and efficient conduct of flights. e) Notify appropriate organizations regarding aircraft in need of search and rescue aid, and assist such organizations as required. Provision of Air Traffic Services: The provision of air traffic control service for controlled flights, except for those parts of such flights which are under the jurisdiction of Approach Control or Aerodrome Control to accomplish following objectives: a) Prevent collisions between aircraft; b) Expedite and maintain an orderly flow of air traffic; Approach control service The provision of air traffic control service for those parts of controlled flights associated with arrival or departure, in order to accomplish following objectives: a) Prevent collisions between aircraft; b) Expedite and maintain an orderly flow of air traffic; Aerodrome control service: The provision of air traffic control service for aerodrome traffic, except for those parts of flights which are under the jurisdiction Approach Control to accomplish objectives: a) Prevent collisions between aircraft; b) Prevent collisions between aircraft on the maneuvering area and obstructions on that area; c) Expedite and maintain an orderly flow of air traffic; Flight information service The flight information service, to accomplish following objective: Provide advice and information useful for the safe and efficient conduct of flights. Alerting service The alerting service to accomplish following objective: Notify appropriate organizations regarding aircraft in need of search and rescue aid and assist such organizations as required.

5. Explain with the help of a neat diagram the principle of secondary radar. Ans:

Secondary radar units work according to principle: The secondary radar unit transmits and also receives high-frequency impulses, the so called interrogation. This isn't simply reflected, but received by the target by means of a transponder which receives and processes. After this the target answers with another frequency, the response telegram which is produced and transmitted. The big difference with SSR is that it doesn't rely on reflections. Aircraft are equipped with a transponder. This transponder transmits a 'reply' when it receives a radar 'interrogation' signal. The interrogation signal is completely separate from any primary signal. As the reply is not just a reflection much less power is needed, typically around 1kW for interrogation pulses, slightly less for replies. Range and direction can be determined from the SSR signal in much the same way as with primary radar, measuring the time between sending the interrogation and receiving the reply, making allowance for the turn-round delay in the transponder. The advantage of SSR is that all sorts of information can be encoded into the Transponder's reply.



Transponders are linked directly to the aircraft's altimeter. The reply contains the aircraft's height, and thus the controller's screen displays the height against the trace. The transponder can also provide identification information, so the controller knows which trace is which aircraft. The pilot can select codes to relay a variety of information including, but not limited to, various emergencies such as hijacks. The same basic system is used by the military - called IFF (Identification Friend or Foe) - to identify 'friendly' aircraft. Radar beams travel in straight lines. Even in flat terrain the curvature of the earth provides a radar shadow - the greater the range, the higher a target must be to allow detection. For example, at a range of 250 miles an aircraft would have to be over 30,000ft1. Thus it is possible to 'fly under the radar'. The problem is, the closer the aircraft gets, the lower it has to fly. Eventually it can no longer hide under the horizon and can only avoid detection if there are radar shadows from hills and mountains etc. By flying dangerously close to the ground, it is possible, in hilly terrain, to get relatively close and still avoid detection, until you fly into that hilly terrain. The latest SSR systems use a system call mode 'S'. It is fitted on larger aircraft and allows interrogation to be 'addressed' to specific aircraft. The system remembers where individual aircraft are and interrogates specific aircraft one at a time, and only in the part of the sky where they are known to be. This reduces unwanted replies and general radio frequency pollution. It also allows much more information to be exchanged. Mode S transponders are also an essential part of the airborne collision avoidance system.

6. What are the advantages of using secondary radar over primary radar? Ans:

Advantages of using Secondary Radar over Primary Radar: The basic function of an air traffic control radar surveillance system is to provide the controller continuously with information on the position and direction of movement of all aircraft within its surveillance area under all weather conditions. Although primary radar has done much to speed the handling of aircraft it has not done all that is required because of certain shortcomings inherent in the primary radar system itself. Thus existing primary radar installations frequently fail to satisfy their intended function for the following reasons:-



(a) The performance can be seriously degraded by precipitation and other weather phenomena. (b) The distance to which an aircraft can be tracked is dependent on the aircraft which can vary with the type size configuration and altitude of the aircraft. (c) In many areas the utility of the radar is impaired due to the presence of ground clutter even when the radar is equipped with MTI. Further the use of MTI introduces certain undesirable limitations. (d) At certain vertical angles and certain distance the performance can frequently be such that continuity of tracking on the display cannot be assured. (e) All echoes on the display are substantially the same in character and in themselves given no clue to aircraft identity Compared with primary radar the advantages of SSR as a separate display can be summarized as follows:- (a) A much clearer display presentation free of clutter from weather, permanent echoes or angels because the ground to-air and air-to-ground signals are transmitted on separate frequency. (b) A reduction in the number and length of RTF transmission necessary for identification or re-identification because this function is automatic requires only a pushbutton function in the cockpit. (c) An immediate indication of flight level (when MODE C is available). (d) Increased coverage regardless of poor primary radar target characteristics of aircraft. Or the answer can be written as follows: Secondary Surveillance Radar (SSR) The Secondary Surveillance Radar system—or Air Traffic Control Radar Beacon System (ATCRBS) as it is sometimes referred to—is comprised of the ATC radar installation and a transponder that rides onboard the aircraft being monitored. The origins of SSR lie in the "identify friend or foe" system used by the military to distinguish allied and enemy aircraft. While a Primary Surveillance Radar listens for reflected radio signals, the Secondary Surveillance Radar listens for messages from the aircraft's transponder. The radar rotates about the vertical axis similar to a PSR, but transmits a specific signal on 1030 MHz. This signal is subsequently received by the aircraft's onboard transponder, which responds with a reply on 1090 MHz. Much like the PSR, the bearing and distance of the aircraft with respect to the radar installation can be calculated with precise knowledge of the orientation of the radar when the signal was transmitted. The SSR system has many advantages over PSR.

1. Since it doesn't rely on radio waves being reflected back by the aircraft, the radar cross section of the aircraft does not form a part of the equation. All aircraft in range of the radar, regardless of size, composition, or distance from the radar, can be "heard" equally well.

2. Because the reply signal is transmitted from the aircraft it is much stronger when received at the ground station, thus giving the possibility of much greater range and reducing the problems of signal attenuation;

3. The transmitting power required of the ground station for a given range is much reduced, thus providing considerable economy;

4. Since the signal received by the radar originates on the aircraft, the signal is subject to less attenuation compared to a PSR signal. This is because the reflected PSR signal has to travel twice as much as the SSR signal. This also implies that the signal transmission power for an SSR can be much lower than that of a PSR.

5. Because the signals in each direction are electronically coded the possibility is offered to transmit additional information between the two stations.



6. Application of secondary radar systems are Traffic Collision Avoidance System (TCAS), Selective Identification System (SIF), Air Traffic Control Radar Beacon System (ATCRBS), Instrument Landing System (ILS), Tactical Air Navigation (TACAN), Navigation Systems (VOR, GPS, DME), Radar Altimeter, Jamming, Electronic warfare, Second Time Round Returns (STRR), Identification –friend or foe radar (IFF)

7. With the help of a neat diagram explain the characteristics of primary runway for

aerodrome category- 4E. Ans:

Aerodrome category – 4E The aerodrome facility reference code, also to be known as the aerodrome reference code, is a two-element, alpha-numeric notation (for example 1B, 3C) derived from the critical aeroplane for that aerodrome facility. The code number is based on the aeroplane reference field length and the code letter is based on the aeroplane wing span and the outer main gear wheel span. The aerodrome reference code provides a method of grouping aeroplanes with different characteristics (eg. wing span, outer main gear wheel span, approach speed and all-up mass) which behave similarly when landing, taking-off or taxying. As the aerodrome reference code notation is derived from aeroplane and not aerodrome characteristics, it applies to the individual aerodrome facilities (eg, runways and taxiways) and indicate their suitability for use by specific groups of aeroplanes. In many cases to determine the appropriate design standard for an aerodrome facility, it is necessary first to identify the aeroplanes for which the facility is intended, and then to determine the aerodrome reference code notation for the most critical of these aeroplanes. The particular standard for the facility is then related to the more demanding of the two criteria (the number or the letter) or to an appropriate combination of both.



At aerodromes with more than one runway, the runways are classified as either primary or secondary runways. The primary runway of an aerodrome is the runway used in preference to others whenever conditions permit. It is generally the longest runway and aligned closest to the direction of the prevailing wind. The other runways are classified as secondary runways. Characteristics of Primary Runway for the aerodrome category- 4E: RUNWAY WIDTH The appropriate runway width requirement may be determined by cross-reference to Table 7–4 using the critical aeroplane reference code. The runway width standards specified in the table are to be used for the construction of a new runway or the upgrading of an existing runway.

TURNING NODES

It may be desirable to widen runway ends to assist aeroplanes during turning manoeuvres and to reduce scuffing of the runway surface. Where a parallel taxiway and taxiway exits are not provided, it may be desirable to provide intermediate turning nodes to allow aeroplanes to turn at the end of the landing run without having to taxi to the end of the runway. The provision of intermediate turning nodes is a financial matter which should be negotiated between aerodrome operators and aircraft operators.

Where an entrance taxiway is not provided at a runway end and the normal turning radius (r) of the critical aeroplane is such that the turning circle is greater than the runway width, a turning node is to be provided. The width of the turning node is to be such that the clearance distance



(y) between the outer main wheel and the edge of the pavement is not less than the dimensions set out in Table 7 –5, and the nose wheel is to remain on the pavement.

LONGITUDINAL SLOPES ON RUNWAYS

Runway design should aim at minimising the overall runway slope to minimise runway length. Accordingly, the ratio computed by dividing the difference between the maximum and minimum elevation along the runway centre line by the runway length, should not exceed:

(a) 1% where the runway is to accommodate aircraft with a code number of 3 or 4;

Along any portion of a runway, the longitudinal slope is not to exceed:

(a) 1.25% where the runway is to accommodate aircraft with a code number of 4, except that for the first and last quarter of the length of the runway, the longitudinal slope is not to exceed 0.8%;

Longitudinal slope changes on runways

Sudden changes in the longitudinal slope of a runway should be avoided as they can cause high acceleration forces which affect passenger comfort and, depending on the aeroplane operating velocity and the severity of the slope change, may reduce the controllability of the aeroplane on the runway. Where slope changes cannot be avoided, the change in slope between two contiguous sections of the runway is not to exceed:

(a) 1.5% where the runway is to accommodate aircraft with a code number of 3 or 4;

The transition from one slope to the next is to be a vertical curve, with a rate of change not exceeding:

(a) 0.1% per 30m (that is, a minimum radius of curvature of 30000m) where the runway is to accommodate aircraft with a code number of 4;



Distance between longitudinal slope changes on runways

Because riding quality is adversely affected by close spacing between, longitudinal slope changes on a runway, undulations or appreciable changes in slopes located close together along a runway should be avoided. To prevent possible loss of control through premature lift off or bouncing of aircraft, the distance (D) between the points of intersection of two successive curves is to be not less than (a) or (b) below, whichever is the greater:

(a) The sum of the absolute values of the corresponding slope changes,(x, y, z) multiplied by the appropriate value of the radius of curvature (k) as follows:

D = k(|x-y|+|y-z|)/100 metres, where

x, y and z are in percentages

k = 30 000m where the runway can accommodate aircraft with a code number of 4 (b) D = 45m

The following diagram illustrates the distance (D) and the slope changes (x, y, z) between the points of intersection of two successive curves on a runway as defined above.

RUNWAY SIGHT DISTANCE

Runway sight distance is the distance along a runway, ahead of an observer in an aircraft cockpit, along which there is an unobstructed line of sight to an object on the runway. The observer's eye level is defined as 1.5m, 2.0m and 3.0m above the runway, depending on the runway code letter.

The purpose of providing adequate runway sight distance is to provide sufficient runway length to allow for the pilot of an aircraft after sighting an object, to react and take appropriate evasive action, for example, braking, exiting the runway or taking-off over the object.

Every runway is to have a longitudinal profile along its centre line such that there will be an unobstructed line of sight from:

(a) any point 3m above the runway centre line to all other points 3m above the centre line, within a distance of at least half the length of the runway, where the runway is to accommodate aircraft with a code letter of C, D or E;

TRANSVERSE SLOPES ON RUNWAYS

The determination of transverse slopes results from balancing two opposing requirements. On one hand there is an advantage in providing relatively steep runway cross slopes for runway pavement drainage. This minimises the risks associated with aircraft aquaplaning and reduced pavement friction due to water build-up on the runway. On the other hand, the provision of relatively flat cross slopes on a runway is desirable from the standpoint of aircraft controllability,



since the greater the cross slope the greater the tendency for aircraft to run off the pavement. To meet these requirements the runway should be built with a central crown.

The runway transverse slope measured from the crown to the runway edge is to be consistent with Table 7–6.

Runway shoulder width Runway shoulders are to be provided for all sealed, asphalt or concrete runway and stop-way pavements where either:

(a) The runway is to accommodate aircraft with a code letter of D or E and the runway width is less than 60m;

Runway shoulder slope The transverse slope of a runway shoulder is not to exceed:

(a) 2.5% where the runway is to accommodate aircraft with a code letter of D or E; Runway strip length The runway strip is to extend beyond the end of the runway or stop-way, if provided, for a distance of 30m for code 1 runways and 60m for code 2, 3 and 4 runways. Runway strip width A non-instrument runway is to be centrally located within a graded runway strip the width of which is shown in Table 7–7: A non-precision approach runway is to be centrally located within a runway strip consisting of a graded portion and a fly-over area such that the overall strip width is as shown in Table 7–8:

A precision approach runway is to be centrally located within a runway strip consisting of a graded portion and a fly-over area such that the overall strip width is as shown in Table 7–9:



Runway strip grading for precision approach runways For precision approach runways code 3 and 4, it is recommended that an additional width of graded runway strip be provided. In this case, the graded width extends to a distance of 105m from the runway centre line, except that the width is gradually reduced (over a distance of 150m) to 75m from the runway centre line at both ends of the strip, for a length of 150m from the runway ends, as shown in the diagram below:

NB: Here I have given the maximum points for answering to aerodrome reference point 4E. Take only the points from the table and write so that the writings will be very less. Here the question has asked to discuss the characteristic of aerodrome reference code 4E

8. Explain in detail the separation standards used in the provision of Approach control service

Ans: Separation Standards used in the provision of Approach control service: 1 Vertical or horizontal separation shall be provided between: a) All aircraft operating in Class A and B airspace; b) IFR flights in Class C airspace; c) IFR flights and VFR flights in Class C airspace; d) IFR flights and special VFR flights; e) Special VFR flights. 2 Wake Turbulence separation standards will be applied as follows:



Note 1: For the application of wake turbulence separation, aircraft are grouped into three categories, as follows:

a) HEAVY - aircraft types of 136,000kg or more: b) MEDIUM - aircraft types less than 136,000kg but more than 7,000kg; and c) LIGHT - aircraft types of 7,000kg or less. Note 2: The minimum radar standard or the applicable wake turbulence standard, whichever is the greater, will be applied. 3 Pilots-in-command of departing aircraft may choose to commence take-off without the applicable wake turbulence standard being applied. In this event the following conditions shall apply: a) The pilot-in-command shall expressly initiate the request for waiver. b) Waiver on the wake turbulence standard shall apply in VMC by day. c) The waiver shall not apply to a LIGHT or MEDIUM aircraft taking off behind a HEAVY aircraft take-off, if the take-off by the LIGHT or MEDIUM aircraft is commenced from a point more than 150 meters along the runway in the direction of take-off, from the commencement point of the HEAVY aircraft take-off. 4 When a pilot-in-command accepts responsibility for wake turbulence separation from another aircraft, the pilot acknowledges that air traffic control will no longer be responsible for the application of wake turbulence separation standards to that specific flight operation.

9. Explain with neat diagram the separation being followed using VOR,NDB,DR, DME Ans: Horizontal Separation An ‘exact reporting point’ is a position established by a navigational facility which is: a) Overhead a VOR. b) Overhead an NDB. c) A position which has been notified as a reporting point and which is established by the intersection of VOR radials. d) A position which has been notified as a reporting point and which is established by the intersection of a VOR radial and a bearing from a NDB. e) A position established by a VOR radial combined with a range from a co-located DME. f) A recognized and published RNAV reporting point. Lateral Separation 1. Lateral separation shall be applied so that the distance between aircraft is never less than a specified amount. It is achieved by requiring aircraft to fly on different tracks or in different geographical locations as determined by visual observations, the use of navigational aids or by the use of area navigation (RNAV) equipment. 2 Communication must be maintained with the aircraft concerned throughout the period that measured distance values are being used to achieve separation. Separation is to be checked by obtaining simultaneous DME readings from aircraft at intervals of not more than 10 minutes. 3 Where measured distance values are used, each aircraft must be using the same ‘on track ’VOR/DME facility i.e. it means that the aircraft is flying either directly inbound to or directly outbound from the station. 4 VOR/DME separation criteria are based on the condition that a VOR and its associated DME station are co-located (600 metres). 5 Aircraft must be within the designated operational coverage (protected range) of a VOR or a NDB. Geographical Separation 1 This separation is only to be used in specific instances as authorized by the relevant authority and published in the appropriate documentation. 2 Such a separation shall be referred to as a “deemed separation” and shall be supported on merit by a safety case.



2. Lateral Separation on Departure or En-route; Both Aircraft Outbound Using VOR radials. 1 Separation is established when; a) Both aircraft have reported established on radials which diverge by 20 degrees or more; b) One aircraft is the time equivalent of 15 NM or 4 minutes (whichever is the greater) based on the speed of 225kts from the VOR; and c) Where only one aircraft has departed from the aerodrome where the VOR is situated, or passed overhead the VOR en-route facility, the time equivalent of 15 NM or 4 minutes(whichever is the greater) based on the speed of 225kts shall be based on the aircraft which departed from the aerodrome where the VOR is situated or passed overhead the VOR facility; and d) If the aircraft’s speed is less than 225kts, additional time shall be added to take into account the aircraft’s speed /performance.

2 Separation is established when both aircraft have reported established on radials which diverge by 60 degrees or more.

3. Lateral Separation on Departure or En-route; Both Aircraft Outbound Using VOR radials and a co-located DME station. 1 Separation is established when; a) Both aircraft report established on radials which diverge by 20 degrees or more; and b) One aircraft is at least 15 DME from the VOR station; and



c) At least one aircraft has departed or passed overhead the VOR facility.

2 Separation is established when; a) Both aircraft report established on radials which diverge by 30 degrees or more; and b) One aircraft is 10 DME from the VOR station; and c) At least one aircraft has departed or passed overhead the VOR facility.

4. Lateral Separation for Departure or En-route; Both Aircraft outbound using an NDB 1 Separation is established when; a) Both aircraft have reported established on tracks which diverge by 30 degrees or more; b) One aircraft is the time equivalent of 15 NM or 4 minutes (whichever is the greater)based on the speed of 225kts from the NDB; and c) Where only one aircraft has departed from the aerodrome where the NDB is situated, or passed overhead the NDB en-route facility, the time equivalent of 15 NM or 4 minutes (whichever is the greater) based on the speed of 225kts shall be based on the aircraft which departed from the aerodrome where the NDB is situated or passed overhead the NDB facility; and d) If the aircraft speed is less than 225 kts, additional time shall be added to take into account the aircraft speed/performance.

2 Separation is established when both aircraft report established on tracks which diverge by 90 degrees or more.



5. Lateral Separation between Aircraft Inbound and Outbound Using VOR radials and a Collocated DME Station. 1 Separation is established when; a) Both aircraft report established on radials at least 30 degrees apart; and b) The outbound aircraft has reported at least 30 DME outbound from the VOR station.

2 Separation is established when; a) Both aircraft report established on radials at least 60 degrees apart; and b) The outbound aircraft has reported at least 15 DME outbound from the VOR station.

6 Lateral Separation When Both Aircraft Are Inbound Using VOR radials and a Co-located DME Station. 1 Separation is established when; a) Both aircraft report established on radials 30 degrees apart; and



b) One aircraft is at least 30 DME from the VOR station.

2 Separation is established when; a) Both aircraft report established on radials 60 degrees apart; and b) One aircraft is at least 15 DME from the VOR station.

10. Write in brief – Aerodrome reference code, aerodrome reference point, aerodrome

reference temperature Ans: Aerodrome Reference Code:

The aerodrome facility reference code, also to be known as the aerodrome reference code, is a two-element, alpha-numeric notation (for example 1B, 3C) derived from the critical aeroplane for that aerodrome facility. The code number is based on the aeroplane reference field length and the code letter is based on the aeroplane wing span and the outer main gear wheel span. The aerodrome reference code provides a method of grouping aeroplanes with different characteristics (eg. wing span, outer main gear wheel span, approach speed and all-up mass) which behave similarly when landing, taking-off or taxying. As the aerodrome reference code notation is derived from aeroplane and not aerodrome characteristics, it applies to the individual aerodrome facilities (eg, runways and taxiways) and indicate their suitability for use by specific groups of aeroplanes. In many cases to determine the appropriate design standard for an aerodrome facility, it is necessary first to identify the aeroplanes for which the facility is intended, and then to determine the aerodrome reference code notation for the most critical of these aeroplanes. The particular standard for the facility is then related to the more demanding of the two criteria (the number or the letter) or to an appropriate combination of both.



At aerodromes with more than one runway, the runways are classified as either primary or secondary runways. The primary runway of an aerodrome is the runway used in preference to others whenever conditions permit. It is generally the longest runway and aligned closest to the direction of the prevailing wind. The other runways are classified as secondary runways.

Aerodrome Reference Point 1 An aerodrome reference point shall be established for an aerodrome. 2 The aerodrome reference point shall be located near the initial or planned geometric centre of the aerodrome and shall normally remain where first established.



3 The position of the aerodrome reference point shall be measured and reported to the aeronautical information services authority in degrees, minutes and seconds. Aerodrome Reference Temperature 1 An aerodrome reference temperature shall be determined for an aerodrome in degrees Celsius. 2 The aerodrome reference temperature shall be the monthly mean of the daily maximum temperatures for the hottest month of the year (the hottest month being that which has the highest monthly mean temperature). This temperature shall be averaged over a period of years.

11. Explain in detail the Phases of Emergencies Ans: PHASES OF EMERGENCY Emergency phases are described as follows:

a. Uncertainty Phase: a situation wherein uncertainty exists as to the safety of an aircraft and its occupants.

b. Alert Phase: a situation wherein apprehension exists as to the safety of an aircraft and its occupants.

c. Distress Phase: a situation wherein there is reasonable certainty that an aircraft and its occupants are threatened by grave and imminent danger or require immediate assistance.

a. Uncertainty phase (INCERFA). A situation when there is concern about the safety of an aircraft or its occupants, an INCERFA exists: 1. When communication from an aircraft has not been received within 30 minutes after the time a communication should have been received or after the time an unsuccessful attempt to establish communication with such aircraft was first made, whichever is earlier; or 2. When an aircraft fails to arrive within 30 minutes after the time of arrival last estimated by the pilot or by the ATC units, whichever is later. b. Alert phase (ALERFA). A situation when there is apprehension about the safety of an aircraft and its occupants, an ALERFA exists: 1. Following the uncertainty phase when subsequent attempts to establish communications with the aircraft, or inquiries to other relevant sources have failed to reveal any information about the aircraft; or 2. When information has been received which indicates that the operating efficiency of the aircraft has been impaired but not to the extent that a forced landing is likely; or 3. When communication from an aircraft has not been received within 60 minutes after the time a communication should have been received or after the time an unsuccessful attempt to establish communication with such aircraft was first made, whichever is earlier. c. Distress phase (DETRESFA): A situation when there is reasonable certainty that the aircraft and its occupants are threatened by grave and imminent danger or require an immediate assistance, a DETRESFA exists: 1. Following the alert phase when further attempts to establish communications with the aircraft and more widespread inquiries are unsuccessful; or 2. When the fuel on board is considered to be exhausted or to be insufficient for the aircraft to reach safety; or 3. When information is received which indicates that the operating efficiency of the aircraft has been impaired to the extent that a forced landing is likely; or 4. When information is received or it is reasonably certain that the aircraft is about to make or has made a forced landing.



In the event of INCERFA, ALERFA, or DETRESFA , notify the following: 1. When practicable, the aircraft operator. 2. The appropriate RCC. 3. Aeronautical stations having en route communications guard responsibilities at the point of departure, along or adjacent to the route of flight, and at the destination. 4. ACCs having jurisdiction over the proposed route of flight from the last reported position to the destination airport. INCERFA, ALERFA, and DETRESFA messages must include the following information, if available, in the order listed: 1. INCERFA, ALERFA, or DETRESFA according to the phase of the emergency. 2. Agency and person originating the message. 3. Nature of the emergency. 4. Significant flight plan information. 5. The air traffic unit which made the last radio contact, the time, and the frequency used. 6. The aircraft's last position report, how it was received, and what facility received it. 7. Color and distinctive marks of aircraft. 8. Any action taken by reporting office. 9. Other pertinent remarks. 1. An INCERFA phase ends with the receipt of any information or position report on the aircraft. Cancel the INCERFA by a message addressed to the same stations as the INCERFA message. 2. An ALERFA ends when: (a) Evidence exists that would ease apprehension about the safety of the aircraft and its occupants; or (b) The concerned aircraft lands. Cancel the ALERFA message by a message addressed to the same stations as the ALERFA message. 3. A DETRESFA ends when the: (a) Aircraft successfully lands; or (b) RCC advises of a successful rescue; or (c) RCC advises of termination of SAR activities. Cancel the DETRESFA by a message addressed to the same stations as the DETRESFA message.

A separate chronological record should be kept on each ALERFA and DETRESFA together with a chart which displays the projected route of the aircraft, position reports received, route of interceptor aircraft, and other pertinent information.

12. With the help of suitable diagram describe the obstacle restrictions in the design of an aerodrome.

Ans: OBSTACLE RESTRICTION: It defines the airspace around aerodromes to be maintained free from obstacles so as to permit the intended aero-plane operations at the aerodromes to be conducted safely and to prevent the aerodromes from becoming unusable by the growth of obstacles around the aerodromes. This is achieved by establishing a series of obstacle limitation surfaces that define the limits to which objects may project into the airspace. The shielding principles to be used for assessing whether an existing obstacle shields another one or a new one. An aerodrome operator shall establish a systematic means of surveying and monitoring any object that penetrates these surfaces and report any penetration immediately to the Authority’s Safety Division and to promulgate them through the Aeronautical Information



Services and air traffic services unit so that aero-plane operations can be conducted safely at all times. When requested, an aerodrome operator shall also work jointly with the Authority’s Safety Division to plan and determine the allowable height limits for new developments in the vicinity of and outside its aerodrome and the type of instrument or visual flight operations that may be permitted taking the obstacle survey plan into account. Obstacle limitation surfaces:

Outer Horizontal Surface: Conical Surface: A surface sloping upwards and outwards from the periphery of the inner horizontal surface. The limits of the conical surface shall comprise: a) A lower edge coincident with the periphery of the inner horizontal surface; and b) An upper edge located at a specified height above the inner horizontal surface. The slope of the conical surface shall be measured in a vertical plane perpendicular to the periphery of the inner horizontal surface. Inner horizontal surface: Inner horizontal surface. A surface located in a horizontal plane above an aerodrome and its environs. The radius or outer limits of the inner horizontal surface shall



be measured from a reference point or points established for such purpose. The height of the inner horizontal surface shall be measured above an elevation datum established for such purpose. Approach surface: An inclined plane or combination of planes preceding the threshold. The limits of the approach surface shall comprise: a) An inner edge of specified length, horizontal and perpendicular to the extended centre line of the runway and located at a specified distance before the threshold; b) Two sides originating at the ends of the inner edge and diverging uniformly at a specified rate from the extended centre line of the runway; and

c) An outer edge parallel to the inner edge. d) The above surfaces shall be varied when lateral offset, offset or curved approaches are utilized, specifically, two sides originating at the ends of the inner edge and diverging uniformly at a specified rate from the extended centre line of the lateral offset, offset or curved ground track. The elevation of the inner edge shall be equal to the elevation of the midpoint of the threshold. The slope(s) of the approach surface shall be measured in the vertical plane containing the centre line of the runway. Inner approach surface: A rectangular portion of the approach surface immediately preceding the threshold. The limits of the inner approach surface shall comprise: a) An inner edge coincident with the location of the inner edge of the approach surface but of its own specified length; b) Two sides originating at the ends of the inner edge and extending parallel to the vertical plane containing the centre line of the runway; and c) An outer edge parallel to the inner edge. Transitional surface: A complex surface along the side of the strip and part of the side of the approach surface, the slopes upwards and outwards to the inner horizontal surface. The limits of the transitional surface shall comprise: a) A lower edge beginning at the intersection of the side of the approach surface with the inner horizontal surface and extending down the side of the approach surface to the inner edge of the approach surface and from there along the length of the strip parallel to the runway centre line; and b) An upper edge located in the plane in the inner horizontal surface. The elevation of a point on the lower edge shall be: a) Along the side of the approach surface – equal to the elevation of the approach surface at that point; and b) Along the strip – equal to the elevation of the nearest point on the centre line of the runway or its extension. The slope of the transitional surface shall be measured in a vertical plane at right angles to the centre line of the runway. Inner transitional surface: A surface similar to the transitional surface but closer to the runway. The limits of an inner transitional surface shall comprise: a) A lower edge beginning at the end of the inner approach surface and extending down the side of the inner approach surface to the inner edge of that surface, from there along the strip parallel to the runway centre line to the inner edge of the balked landing surface and from there up the side of the balked landing surface to the point where the side intersects the inner horizontal surface; and b) An upper edge located in the plane of the inner horizontal surface. The elevation of a point on the lower edge shall be: a) Along the side of the inner approach surface and balked landing surface – equal to the elevation of the particular surface at that point; and b) Along the strip – equal to the elevation of the nearest point on the centre line of the runway or its extension.



The slope of inner transitional surface shall be measured in a vertical plane at right angles to the centre line of the runway. Balked landing surface: An inclined plane located at a specified distance after the threshold, extending between the inner transitional surfaces. The limits of the balked landing surface shall comprise: a) An inner edge horizontal and perpendicular to the centre line of the runway and location at a specified distance after the threshold; b) Two sides originating at the ends of the inner edge and diverging uniformly at a specified rate from the vertical plane containing the centre line of the runway; and c) An outer edge parallel to the inner edge and located in the plane of the inner horizontal surface. The elevation of the inner edge shall be equal to the elevation of the runway centre line at the location of the inner edge. The slope of the balked landing surface shall be measured in the vertical plane containing the centre line of the runway. Take-off climb surface: An inclined plane or other specified surface beyond the end of a runway or clearway. The limits of the take-off climb surface shall comprise: a) An inner edge horizontal and perpendicular to the centre line of the runway and located either at a specified distance beyond the end of the runway or at the end of the clearway when such is provided and its length exceeds the specified distance; b) Two sides originating at the ends of the inner edge, diverging uniformly at a specified rate from the take-off track to a specified final width and continuing thereafter at that width for the remainder of the length of the take-off climb surface; and c) An outer edge horizontal and perpendicular to the specified takeoff track. The elevation of the inner edge shall be equal to the highest point on the runway centre line between the end of the runway and the inner edge, except that when a clearway is provided the elevation shall be equal to the highest point on the ground on the centre line of the clearway. In the case of a straight take-off flight path, the slope of the take-off climb surface shall be measured in the vertical plane containing the centre line of the runway. In the case of a take-off flight path involving a turn, the take-off climb surface shall be a complex surface containing the horizontal normal to its centre line, and the slope of the centre line shall be the same as that for a straight takeoff flight path. Obstacle limitation requirements: Non-instrument runways The following obstacle limitation surfaces shall be established for a non-instrument runway. — Conical surface; — Inner horizontal surface; — Approach surface; and — Transitional surfaces. Non-precision approach runway The following obstacle limitation surfaces shall be established for a non precision approach runway: — Conical surface; — Inner horizontal surface; — Approach surface; and — Transitional surfaces. The approach surface shall be horizontal beyond the point at which the 2.5 per cent slope intersects: a) A horizontal plane 150m above the threshold elevation; or b) The horizontal plane passing through the top of any object that governs the obstacle clearance altitude/height (OCA/H); whichever is the higher.



New objects or extensions of existing objects shall not be permitted above an approach surface within 3,000m of the inner edge or above a transitional surface except when the new object or extension would be shielded by an existing immovable object. Precision approach runways The following obstacle limitation surfaces shall be established for a precision approach runway category I: – Conical surface; – Inner horizontal surface; – Approach surface; and – Transitional surfaces. The following obstacle limitation surfaces shall be established for a precision approach runway category I: – Inner approach surface; – Inner transitional surfaces; and – Balked landing surface. The following obstacle limitation surfaces shall be established for a precision approach runway category II. – Conical surface; – Inner horizontal surface; – Approach surface and inner approach surface; – Transitional surfaces; – Inner transitional surfaces; and

– Balked landing surface. Runways meant for take-off The following obstacle limitation surface shall be established for a runway meant for take-off: – Take-off climb surface. 13. Explain RNAV & RNP in detail Ans:

Area Navigation (RNAV) : RNAV is a method of navigation that permits aircraft operation on any desired flight path within the coverage of ground or space based navigation aids or within the limits of the capability of self-contained aids, or a combination of these. In the future, there will be an increased dependence on the use of RNAV in lieu of routes defined by ground-based navigation aids. RNAV routes and terminal procedures, including departure procedures (DPs) and standard terminal arrivals (STARs), are designed with RNAV systems in mind. There are several potential advantages of RNAV routes and procedures: 1. Time and fuel savings, 2. Reduced dependence on radar vectoring, altitude, and speed assignments allowing a reduction in required ATC radio transmissions, and 3. More efficient use of airspace. RNAV Operations: RNAV procedures, such as DPs and STARs, demand strict pilot awareness and maintenance of the procedure centerline. Pilots should possess a working knowledge of their aircraft navigation system to ensure RNAV procedures are flown in an appropriate manner. In addition, pilots should have an understanding of the various waypoint and leg types used in RNAV procedures; these are discussed in more detail below. 1. Waypoints: A waypoint is a predetermined geographical position that is defined in terms of latitude/longitude coordinates. Waypoints may be a simple named point in space or associated with existing nav-aids, intersections, or fixes. A waypoint is most often used to indicate a change in direction, speed, or altitude along the desired path. RNAV procedures make use of both fly-over and fly-by waypoints.



2. Fly-by waypoints: Fly-by waypoints are used when an aircraft should begin a turn to the next course prior to reaching the waypoint separating the two route segments. This is known as turn anticipation. 3. Fly-over waypoints: Fly-over waypoints are used when the aircraft must fly over the point prior to starting a turn.

RNAV Leg Types: A leg type describes the desired path proceeding, following, or between waypoints on an RNAV procedure. Leg types are identified by a two-letter code that describes the path (e.g., heading, course, track, etc.) and the termination point (e.g., the path terminates at an altitude, distance, fix, etc.). Leg types used for procedure design are included in the aircraft navigation database, but not normally provided on the procedure chart. The narrative depiction of the RNAV chart describes how a procedure is flown. The “path and terminator concept” defines that every leg of a procedure has a termination point and some kind of path into that termination point. Some of the available leg types are described below. (a) Track to Fix: A Track to Fix (TF) leg is intercepted and acquired as the flight track to the following waypoint. Track to a Fix legs are sometimes called point-to-point legs for this reason. Narrative: “on track 087 to CHEZZ WP.”

(b) Direct to Fix: A Direct to Fix (DF) leg is a path described by an aircraft's track from an initial area direct to the next waypoint. Narrative: “left turn direct BARGN WP.” (c) Course to Fix: A Course to Fix (CF) leg is a path that terminates at a fix with a specified course at that fix. Narrative: “on course 078 to PRIMY WP.” (d) Radius to Fix: A Radius to Fix (RF) leg is defined as a constant radius circular path around a defined turn center that terminates at a fix. (e) Heading: A Heading leg may be defined as, but not limited to, a Heading to Altitude (VA), Heading to DME range (VD), and Heading to Manual Termination, i.e., Vector



(VM). Narrative: “climb heading 350 to 1500”, “heading 265, at 9 DME west of PXR VORTAC, right turn heading 360”, “fly heading 090, expect radar vectors to DRYHT INT.”

Required Navigation Performance (RNP): RNP is RNAV with on-board navigation monitoring and alerting, RNP is also a statement of navigation performance necessary for operation within a defined airspace. A critical component of RNP is the ability of the aircraft navigation system to monitor its achieved navigation performance, and to identify for the pilot whether the operational requirement is, or is not being met during an operation. This on-board performance monitoring and alerting capability therefore allows a lessened reliance on air traffic control intervention (via radar monitoring, automatic dependent surveillance (ADS), multilateration, communications), and/or route separation to achieve the overall safety of the operation. RNP capability of the aircraft is a major component in determining the separation criteria to ensure that the overall containment of the operation is met. The RNP capability of an aircraft will vary depending upon the aircraft equipment and the navigation infrastructure. For example, an aircraft may be equipped and certified for RNP 1.0, but may not be capable of RNP 1.0 operations due to limited navaid coverage. RNP Operations: RNP Levels: An RNP “level” or “type” is applicable to a selected airspace, route, or procedure. As defined in the Pilot/Controller Glossary, the RNP Level or Type is a value typically expressed as a distance in nautical miles from the intended centerline of a procedure, route, or path. RNP applications also account for potential errors at some multiple of RNP level (e.g., twice the RNP level). (a) Standard RNP Levels: U.S. standard values supporting typical RNP airspace are as specified in TBL 1-2-1 below. Other RNP levels as identified by ICAO, other states and the FAA may also be used.

(b) Application of Standard RNP Levels: U.S. standard levels of RNP typically used for various routes and procedures supporting RNAV operations may be based on use of a



specific navigational system or sensor such as GPS, or on multi-sensor RNAV systems having suitable performance. (c) Depiction of Standard RNP Levels: The applicable RNP level will be depicted on affected charts and procedures.

14. What are all the visual aids being used in an aerodrome –explain in brief Ans:

Approach Light Systems (ALS) ALS provides the basic means to transition from instrument flight to visual flight for landing. Operational requirements dictate the sophistication and configuration of the approach light system for a particular runway. ALS are a configuration of signal lights starting at the landing threshold and extending into the approach area a distance of 2400-3000 feet for precision instrument runways and 1400-1500 feet for non-precision instrument runways. Some systems include sequenced flashing lights which appear to the pilot as a ball of light traveling towards the runway at high speed (twice a second). Visual Glideslope Indicators: a. Visual Approach Slope Indicator (VASI): 1. VASI installations may consist of either 2, 4, 6, 12, or 16 light units arranged in bars referred to as near, middle, and far bars. Most VASI installations consist of 2 bars, near and far, and may consist of 2, 4, or 12 light units. Some VASIs consist of three bars, near, middle, and far, which provide an additional visual glide path to accommodate high cockpit aircraft. This installation may consist of either 6 or 16 light units. VASI installations consisting of 2, 4, or 6 light units are located on one side of the runway, usually the left. Where the installation consists of 12 or 16 light units, the units are located on both sides of the runway. 2. Two-bar VASI installations provide one visual glide path which is normally set at 3 degrees. Three-bar VASI installations provide two visual glide paths. The lower glide path is provided by the near and middle bars and is normally set at 3 degrees while the upper glide path, provided by the middle and far bars, is normally 1/4 degree higher. This higher glide path is intended for use only by high cockpit aircraft to provide a sufficient threshold crossing height. Although normal glide path angles are three degrees, angles at some locations may be as high as 4.5 degrees to give proper obstacle clearance. Pilots of high performance aircraft are cautioned that use of VASI angles in excess of 3.5 degrees may cause an increase in runway length required for landing and rollout. 3. The basic principle of the VASI is that of color differentiation between red and white. Each light unit projects a beam of light having a white segment in the upper part of the beam and red segment in the lower part of the beam. The light units are arranged so that the pilot using the VASIs during an approach will see the combination of lights shown below. 4. The VASI is a system of lights so arranged to provide visual descent guidance information during the approach to a runway. These lights are visible from 3-5 miles during the day and up to 20 miles or more at night. The visual glide path of the VASI provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 NM from the runway threshold. Descent, using the VASI, should not be initiated until the aircraft is visually aligned with the runway. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced due to local limitations, or the VASI may be offset from the extended runway centerline. This will be noted in the Airport/ Facility Directory. b. Precision Approach Path Indicator (PAPI): The precision approach path indicator (PAPI) uses light units similar to the VASI but are installed in a single row of either two or four light units. These lights are visible from about 5 miles during the day and up to 20 miles at night. The visual glide path of the PAPI typically provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 SM from the runway



threshold. Descent, using the PAPI, should not be initiated until the aircraft is visually aligned with the runway. The row of light units is normally installed on the left side of the runway and the glide path indications are as depicted. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced due to local limitations, or the PAPI may be offset from the extended runway centerline. This will be noted in the Airport/ Facility Directory. (See FIG )

c. Tri-color Systems: Tri-color visual approach slope indicators normally consist of a single light unit projecting a three-color visual approach path into the final approach area of the runway upon which the indicator is installed. The below glide path indication is red, the above glide path indication is amber, and the on glide path indication is green. These types of indicators have a useful range of approximately one-half to one mile during the day and up to five miles at night depending upon the visibility conditions. (See FIG).

d. Pulsating Systems: Pulsating visual approach slope indicators normally consist of a single light unit projecting a two-color visual approach path into the final approach area of the runway upon which the indicator is installed. The on glide path indication is a steady white light. The slightly below glide path indication is a steady red light. If the aircraft descends further below the glide path, the red light starts to pulsate. The above glide path indication is a pulsating white light. The pulsating rate increases as the aircraft gets further above or below the desired glide slope. The useful range of the system is about four miles during the day and up to ten miles at night. (See FIG) e. Alignment of Elements Systems: Alignment of elements systems are installed on some small general aviation airports and are a low-cost system consisting of painted plywood panels, normally black and white or fluorescent orange. Some of these systems are lighted for night use. The useful range of these systems is approximately three-quarter miles. To use the system the pilot positions the aircraft so the elements are in alignment. The glide path indications are shown in FIG. Runway End Identifier Lights (REIL): REILs are installed at many airfields to provide rapid and positive identification of the approach end of a particular runway. The system consists of a pair of synchronized flashing lights located laterally on each side of the runway threshold. REILs may be either omni-directional or unidirectional facing the approach area. They are effective for: a. Identification of a runway surrounded by a preponderance of other lighting. b. Identification of a runway which lacks contrast with surrounding terrain. c. Identification of a runway during reduced visibility.



Runway Edge Light Systems: a. Runway edge lights are used to outline the edges of runways during periods of darkness or restricted visibility conditions. These light systems are classified according to the intensity or brightness they are capable of producing: they are the High Intensity Runway Lights (HIRL), Medium Intensity Runway Lights (MIRL), and the Low Intensity Runway Lights (LIRL). The HIRL and MIRL systems have variable intensity controls, whereas the LIRLs normally have one intensity setting. b. The runway edge lights are white, except on instrument runways yellow replaces white on the last 2,000 feet or half the runway length, whichever is less, to form a caution zone for landings. c. The lights marking the ends of the runway emit red light toward the runway to indicate the end of runway to a departing aircraft and emit green outward from the runway end to indicate the threshold to landing aircraft. In-runway Lighting: a. Runway Centerline Lighting System (RCLS): Runway centerline lights are installed on some precision approach runways to facilitate landing under adverse visibility conditions. They are located along the runway centerline and are spaced at 50-foot intervals. When viewed from the landing threshold, the runway centerline lights are white until the last 3,000 feet of the runway. The white lights begin to alternate with red for the next 2,000 feet, and for the last 1,000 feet of the runway, all centerline lights are red. b. Touchdown Zone Lights (TDZL): Touchdown zone lights are installed on some precision approach runways to indicate the touchdown zone when landing under adverse visibility conditions. They consist of two rows of transverse light bars disposed symmetrically about the runway centerline. The system consists of steady-burning white lights which start 100 feet beyond the landing threshold and extend to 3,000 feet beyond the landing threshold or to the midpoint of the runway, whichever is less. c. Taxiway Centerline Lead-Off Lights: Taxiway centerline lead-off lights provide visual guidance to persons exiting the runway. They are color-coded to warn pilots and vehicle drivers that they are within the runway environment or instrument landing system/microwave landing system (ILS/MLS) critical area, whichever is more restrictive. Alternate green and yellow lights are installed, beginning with green, from the runway centerline to one centerline light position beyond the runway holding position or ILS/MLS critical area holding position. d. Taxiway Centerline Lead-On Lights: Taxiway centerline lead-on lights provide visual guidance to persons entering the runway. These “lead-on” lights are also color-coded with the same color pattern as lead-off lights to warn pilots and vehicle drivers that they are within the runway environment or instrument landing system/microwave landing system (ILS/MLS) critical area, whichever is more conservative. The fixtures used for lead-on lights are bidirectional, i.e., one side emits light for the lead-on function while the other side emits light for the lead-off function. Any fixture that emits yellow light for the lead-off function must also emit yellow light for the lead-on function. e. Land and Hold Short Lights: Land and hold short lights are used to indicate the hold short point on certain runways which are approved for Land and Hold Short Operations (LAHSO). Land and hold short lights consist of a row of pulsing white lights installed across the runway at the hold short point. Where installed, the lights will be on anytime LAHSO is in effect. These lights will be off when LAHSO is not in effect. Runway Status Light (RWSL) System: a. RWSL is a fully automated system that provides runway status information to pilots and surface vehicle operators to clearly indicate when it is unsafe to enter, cross, takeoff from, or land on a runway. The RWSL system processes information from surveillance systems and activates Runway Entrance Lights (REL), Takeoff Hold Lights (THL), Runway Intersection Lights (RIL), and Final Approach Runway Occupancy Signal (FAROS) in accordance with the



position and velocity of the detected surface traffic and approach traffic. REL, THL, and RIL are in-pavement light fixtures that are directly visible to pilots and surface vehicle operators. FARO alerts arriving pilots that the approaching runway is occupied by flashing the Precision Approach Path Indicator (PAPI). FAROS may be implemented as an add-on to the RWSL system or implemented as a standalone system at airports without a RWSL system. RWSL is an independent safety enhancement that does not substitute for or convey an ATC clearance. Clearance to enter, cross, takeoff from, land on, or operate on a runway must still be received from ATC. Although ATC has limited control over the system, personnel do not directly use and may not be able to view light fixture activations and deactivations during the conduct of daily ATC operations. b. Runway Entrance Lights (REL): The REL system is composed of flush mounted, in-pavement, unidirectional light fixtures that are parallel to and focused along the taxiway centerline and directed toward the pilot at the hold line. An array of REL lights include the first light at the hold line followed by a series of evenly spaced lights to the runway edge; one additional light at the runway centerline is in line with the last two lights before the runway edge. When activated, the red lights indicate that there is high speed traffic on the runway or there is an aircraft on final approach within the activation area. c. Takeoff Hold Lights (THL): The THL system is composed of flush mounted, in pavement, unidirectional light fixtures in a double longitudinal row aligned either side of the runway centerline lighting. Fixtures are focused toward the arrival end of the runway at the “line up and wait" point. THLs extend for 1,500 feet in front of the holding aircraft starting at a point 375 feet from the departure threshold. Illuminated red lights provide a signal, to an aircraft in position for takeoff or rolling, that it is unsafe to takeoff because the runway is occupied or about to be occupied by another aircraft or ground vehicle. Two aircraft, or a surface vehicle and an aircraft, are required for the lights to illuminate. The departing aircraft must be in position for takeoff or beginning takeoff roll. Another aircraft or a surface vehicle must be on or about to cross the runway. d. Runway Intersection Lights (RIL): The RIL system is composed of flush mounted, in-pavement; unidirectional light fixtures in a double longitudinal row aligned either side of the runway centerline lighting in the same manner as THLs. Their appearance to a pilot is similar to that of THLs. Fixtures are focused toward the arrival end of the runway, and they extend for 3,000 feet in front of an aircraft that is approaching an intersecting runway. They end at the Land and Hold Short Operation (LASHO) light bar or the hold short line for the intersecting runway. e. The Final Approach Runway Occupancy Signal (FAROS) is communicated by flashing of the Precision Approach Path Indicator (PAPI) (see FIG 219). When activated, the light fixtures of the PAPI flash or pulse to indicate to the pilot on an approach that the runway is occupied and that it may be unsafe to land. Stand Alone Final Approach Runway Occupancy Signal (FAROS): The standalone FAROS system is a fully automated system that provides runway occupancy status to pilots on final approach to indicate whether it may be unsafe to land. When an aircraft or vehicle is detected on the runway, the Precision Approach Path Indicator (PAPI) light fixtures flash as a signal to indicate that the runway is occupied and that it may be unsafe to land. The standalone FAROS system is activated by localized or comprehensive sensors detecting aircraft or ground vehicles occupying activation zones. The standalone FAROS system monitors specific areas of the runway, called activation zones, to determine the presence of aircraft or ground vehicles in the zone. These activation zones are defined as areas on the runway that are frequently occupied by ground traffic during normal airport operations and could present a hazard to landing aircraft. Activation zones may include the full length departure position, the midfield departure position, a frequently crossed intersection, or the entire runway.



Control of Lighting Systems: Operation of approach light systems and runway lighting is controlled by the control tower (ATCT). At some locations the FSS may control the lights where there is no control tower in operation. Pilots may request that lights be turned on or off. Runway edge lights, in-pavement lights and approach lights also have intensity controls which may be varied to meet the pilots request. Sequenced flashing lights (SFL) may be turned on and off. Some sequenced flashing light systems also have intensity control. Pilot Control of Airport Lighting : Radio control of lighting is available at selected airports to provide airborne control of lights by keying the aircraft's microphone. Control of lighting systems is often available at locations without specified hours for lighting and where there is no control tower or FSS or when the tower or FSS is closed (locations with a part-time tower or FSS) or specified hours. All lighting systems which are radio controlled at an airport, whether on a single runway or multiple runways, operate on the same radio frequency. Airport/Heliport Beacons: Airport and heliport beacons have a vertical light distribution to make them most effective from one to ten degrees above the horizon; however, they can be seen well above and below this peak spread. The beacon may be an Omni-directional capacitor-discharge device, or it may rotate at a constant speed which produces the visual effect of flashes at regular intervals. Flashes may be one or two colors alternately. Taxiway Lights: a. Taxiway Edge Lights: Taxiway edge lights are used to outline the edges of taxiways during periods of darkness or restricted visibility conditions. These fixtures emit blue light. b. Taxiway Centerline Lights: Taxiway centerline lights are used to facilitate ground traffic under low visibility conditions. They are located along the taxiway centerline in a straight line on straight portions, on the centerline of curved portions, and along designated taxiing paths in portions of runways, ramp, and apron areas. Taxiway centerline lights are steady burning and emit green light. c. Clearance Bar Lights. Clearance bar lights are installed at holding positions on taxiways in order to increase the conspicuity of the holding position in low visibility conditions. They may also be installed to indicate the location of an intersecting taxiway during periods of darkness. Clearance bars consist of three in-pavement steady-burning yellow lights. d. Runway Guard Lights. Runway guard lights are installed at taxiway/runway intersections. They are primarily used to enhance the conspicuity of taxiway/runway intersections during low visibility conditions, but may be used in all weather conditions. Runway guard lights consist of either a pair of elevated flashing yellow lights installed on either side of the taxiway, or a row of in-pavement yellow lights installed across the entire taxiway, at the runway holding position marking. e. Stop Bar Lights. Stop bar lights, when installed, are used to confirm the ATC clearance to enter or cross the active runway in low visibility conditions (below 1,200 ft Runway Visual Range). A stop bar consists of a row of red, unidirectional, steady-burning in-pavement lights installed across the entire taxiway at the runway holding position, and elevated steady-burning red lights on each side. A controlled stop bar is operated in conjunction with the taxiway centerline lead-on lights which extend from the stop bar toward the runway. Following the ATC clearance to proceed, the stop bar is turned off and the lead-on lights are turned on. The stop bar and lead-on lights are automatically reset by a sensor or backup timer. Aeronautical Light Beacons: An aeronautical light beacon is a visual NAVAID displaying flashes of white and/or colored light to indicate the location of an airport, a heliport, a landmark, a certain point of a Federal airway in mountainous terrain, or an obstruction. The light used may be a rotating beacon or one or more flashing lights. The flashing lights may be supplemented by steady burning lights of lesser intensity.



Code Beacons: The code beacon, which can be seen from all directions, is used to identify airports and landmarks. The code beacon flashes the three or four character airport identifier in International Morse Code six to eight times per minute. Green flashes are displayed for land airports while yellow flashes indicate water airports. Course Lights: The course light, which can be seen clearly from only one direction, is used only with rotating beacons of the Federal Airway System: two course lights, back to back, direct coded flashing beams of light in either direction along the course of airway. Obstruction Lights: Obstructions are marked / lighted to warn airmen of their presence during daytime and nighttime conditions.

15. Explain VAPI and PAPI in detail. Ans: A visual approach slope indicator (VASI or VAPI) system shall be provided to serve the approach to a runway where one or more of the following conditions exits:

- The runway is not served by an electronic glide path and the runway is used by turbojet or other aircraft with similar approach guidance requirements;

- The pilot of any type of aircraft may have difficulty in judging the approach due to:

1. Inadequate visual guidance such as is experienced during an approach over water, 2. or featureless terrain by day or in the absence of sufficient extraneous lights in the

approach area by night, or 3. Misleading information such as is produced by deceptive surrounding terrain or

runway slopes; Visual approach slope indicators (VASI or VAPI) consist of one set of lights set up some seven meters (twenty feet) from the start of the runway. Each light is designed so that the light appears as either white or red, depending on the angle at which the lights are viewed. When the pilot is approaching the lights at the proper angle, meaning the pilot is on the glide slope, the first set of lights appears white and the second set appears red. When both sets appear white, the pilot is flying too high, and when both appear red he or she is flying too low. This is the most common type of visual approach slope indicator system. 1. VASI installations may consist of either 2, 4, 6, 12, or 16 light units arranged in bars referred to as near, middle, and far bars. Most VASI installations consist of 2 bars, near and far, and may consist of 2, 4, or 12 light units. Some VASIs consist of three bars, near, middle, and far, which provide an additional visual glide path to accommodate high cockpit aircraft. This installation may consist of either 6 or 16 light units. VASI installations consisting of 2, 4, or 6 light units are located on one side of the runway, usually the left. Where the installation consists of 12 or 16 light units, the units are located on both sides of the runway. 2. Two-bar VASI installations provide one visual glide path which is normally set at 3 degrees. Three-bar VASI installations provide two visual glide paths. The lower glide path is provided by the near and middle bars and is normally set at 3 degrees while the upper glide path, provided by the middle and far bars, is normally 1/4 degree higher. This higher glide path is intended for use only by high cockpit aircraft to provide a sufficient threshold crossing height. Although normal glide path angles are three degrees, angles at some locations may be as high as 4.5 degrees to give proper obstacle clearance. Pilots of high performance aircraft are cautioned that use of VASI angles in excess of 3.5 degrees may cause an increase in runway length required for landing and rollout. 3. The basic principle of the VASI is that of color differentiation between red and white. Each light unit projects a beam of light having a white segment in the upper part of the beam and red segment in the lower part of the beam. The light units are arranged so that the pilot using the VASIs during an approach will see the combination of lights shown below. 4. The VASI is a system of lights so arranged to provide visual descent guidance information during the approach to a runway. These lights are visible from 3-5 miles during the day



and up to 20 miles or more at night. The visual glide path of the VASI provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 NM from the runway threshold. Descent, using the VASI, should not be initiated until the aircraft is visually aligned with the runway. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced due to local limitations, or the VASI may be offset from the extended runway centerline. This will be noted in the Airport/ Facility Directory.

Precision Approach Path Indicator (PAPI): The precision approach path indicator (PAPI) uses light units similar to the VASI but is installed in a single row of either two or four light units. These lights are visible from about 5 miles during the day and up to 20 miles at night. The visual glide path of the PAPI typically provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 SM from the runway threshold. Descent, using the PAPI, should not be initiated until the aircraft is visually aligned with the runway. The row of light units is normally installed on the left side of the runway and the glide path indications are as depicted. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced due to local limitations, or the PAPI may be offset from the extended runway centerline. This will be noted in the Airport/ Facility Directory. (See FIG )



16. What are all various runway markings for an instrumental runway? Ans: Runway Markings: There are three types of markings for runways: visual, non-precision instrument, and precision instrument. TBL 2-3-1 identifies the marking elements for each type of runway and TBL 2-3-2 identifies runway threshold markings.

Runway Designators; Runway numbers and letters are determined from the approach direction. The runway number is the whole number nearest one‐tenth the magnetic azimuth of the centerline of the runway, measured clockwise from the magnetic north. The letters differentiate between left (L), right (R), or center (C), parallel runways, as applicable: 1. For two parallel runways “L” “R.” 2. For three parallel runways “L” “C” “R.”



Runway Centerline Marking: The runway centerline identifies the center of the runway and provides alignment guidance during takeoff and landings. The centerline consists of a line of uniformly spaced stripes and gaps. Runway Aiming Point Marking: The aiming point marking serves as a visual aiming point for a landing aircraft. These two rectangular markings consist of a broad white stripe located on each side of the runway centerline and approximately 1,000 feet from the landing threshold, as shown in FIG 2-3-1, Precision Instrument Runway Markings. Runway Touchdown Zone Markers: The touchdown zone markings identify the touchdown zone for landing operations and are coded to provide distance information in 500 feet (150m) increments. These markings consist of groups of one, two, and three rectangular bars symmetrically arranged in pairs about the runway centerline, as shown in FIG 2-3-1, Precision Instrument Runway Markings. For runways having touchdown zone markings on both ends, those pairs of markings which extend to within 900 feet (270m) of the midpoint between the thresholds are eliminated. Runway Side Stripe Marking: Runway side stripes delineate the edges of the runway. They provide a visual contrast between runway and the abutting terrain or shoulders. Side stripes consist of continuous white stripes located on each side of the runway as shown in FIG 2-3-4. Runway Shoulder Markings: Runway shoulder stripes may be used to supplement runway side stripes to identify pavement areas contiguous to the runway sides that are not intended for use by aircraft. Runway Shoulder stripes are Yellow. (See FIG 2-3-5.) Runway Threshold Markings: Runway threshold markings come in two configurations. They either consist of eight longitudinal stripes of uniform dimensions disposed symmetrically about the runway centerline, as shown in FIG 2-3-1, or the number of stripes is related to the runway width as indicated in TBL 2-3-2. A threshold marking helps identify the beginning of the runway that is available for landing. In some instances the landing threshold may be relocated or displaced. Demarcation Bar: A demarcation bar delineates a runway with a displaced threshold from a blast pad, stop way or taxiway that precedes the runway. A demarcation bar is 3 feet (1m) wide and yellow, since it is not located on the runway. Runway Threshold Bar: A threshold bar delineates the beginning of the runway that is available for landing when the threshold has been relocated or displaced. A threshold bar is 10 feet (3m) in width and extends across the width of the runway, as shown in FIG 2-3-4.



17. Explain the contents of Position Reports and ATC clearance Ans: Position Reports: Unless exempted by the appropriate ATS authority or by the appropriate air traffic services unit under conditions specified by that authority, a controlled flight shall report to the appropriate air traffic services unit, as soon as possible, the time and level of passing each designated compulsory reporting point, together with any other required information. Position reports shall similarly be made in relation to additional points when requested by the appropriate air traffic services unit. In the absence of designated reporting points, position reports shall be made at intervals prescribed by the appropriate ATS authority or specified by the appropriate air traffic services unit. B. Controlled flights providing position information to the appropriate air traffic services unit via data link communications shall only provide voice position reports when requested. On routes defined by designated significant points, position reports shall be made by the aircraft when over or as soon as possible after passing, each designated compulsory reporting point. Additional reports over other points may be requested by the appropriate ATS unit. Contents of voice position reports: 1) Aircraft identification 2) Position 3) Time 4) Flight level or altitude, including passing level and cleared level if not maintaining the cleared level 5) Next position and time over 6) Ensuing significant point.

ATC clearances normally contain the following: a. Clearance Limit: The traffic clearance issued prior to departure will normally authorize flight to the airport of intended landing. Many airports and associated NAVAIDs are collocated with the same name and/or identifier, so care should be exercised to ensure a clear understanding of the clearance limit. When the clearance limit is the airport of intended landing, the clearance should contain the airport name followed by the word “airport.” Under certain conditions, a clearance limit may be a NAVAID or other fix. When the clearance limit is a NAVAID, intersection, or waypoint and the type is known, the clearance should contain type. Under certain conditions, at some locations a short-range clearance procedure is utilized whereby a clearance is issued to a fix within or just outside of the terminal area and pilots is advised of the frequency on which they will receive the long-range clearance direct from the center controller. b. Departure Procedure: Headings to fly and altitude restrictions may be issued to separate a departure from other air traffic in the terminal area. Where the volume of traffic warrants, DPs have been developed. c. Route of Flight: 1. Clearances are normally issued for the altitude or flight level and route filed by the pilot. However, due to traffic conditions, it is frequently necessary for ATC to specify an altitude or flight level or route different from that requested by the pilot. In addition, flow patterns have been established in certain congested areas or between congested areas whereby traffic capacity is increased by routing all traffic on preferred routes. Information on these flow patterns is available in offices where preflight briefing is furnished or where flight plans are accepted. 2. When required, air traffic clearances include data to assist pilots in identifying radio reporting points. It is the responsibility of pilots to notify ATC immediately if their radio equipment cannot receive the type of signals they must utilize to comply with their clearance. d. Altitude Data: 1. The altitude or flight level instructions in an ATC clearance normally require that a pilot “MAINTAIN” the altitude or flight level at which the flight will operate when in



controlled airspace. Altitude or flight level changes while en route should be requested prior to the time the change is desired. 2. When possible, if the altitude assigned is different from the altitude requested by the pilot, ATC will inform the pilot when to expect climb or descent clearance or to request altitude change from another facility. If this has not been received prior to crossing the boundary of the ATC facility's area and assignment at a different altitude is still desired, the pilot should reinitiate the request with the next facility. 3. The term “cruise” may be used instead of “MAINTAIN” to assign a block of airspace to a pilot from the minimum IFR altitude up to and including the altitude specified in the cruise clearance. The pilot may level off at any intermediate altitude within this block of airspace. Climb/descent within the block is to be made at the discretion of the pilot. However, once the pilot starts descent and verbally reports leaving an altitude in the block, the pilot may not return to that altitude without additional ATC clearance. e. Holding Instructions: 1. Whenever an aircraft has been cleared to a fix other than the destination airport and delay is expected, it is the responsibility of the ATC controller to issue complete holding instructions (unless the pattern is charted), an EFC time, and a best estimate of any additional en route/terminal delay. 2. If the holding pattern is charted and the controller doesn't issue complete holding instructions, the pilot is expected to hold as depicted on the appropriate chart. When the pattern is charted, the controller may omit all holding instructions except the charted holding direction and the statements AS PUBLISHED, e.g., “HOLD EAST AS PUBLISHED.” Controllers must always issue complete holding instructions when pilots request them. 3. If no holding pattern is charted and holding instructions have not been issued, the pilot should ask ATC for holding instructions prior to reaching the fix. This procedure will eliminate the possibility of an aircraft entering a holding pattern other than that desired by ATC. If unable to obtain holding instructions prior to reaching the fix (due to frequency congestion, stuck microphone, etc.), hold in a standard pattern on the course on which you approached the fix and request further clearance as soon as possible. In this event, the altitude/flight level of the aircraft at the clearance limit will be protected so that separation will be provided as required. 4. When an aircraft is 3 minutes or less from a clearance limit and a clearance beyond the fix has not been received, the pilot is expected to start a speed reduction so that the aircraft will cross the fix, initially, at or below the maximum holding airspeed. 5. When no delay is expected, the controller should issue a clearance beyond the fix as soon as possible and, whenever possible, at least 5 minutes before the aircraft reaches the clearance limit. 6. Pilots should report to ATC the time and altitude/flight level at which the aircraft reaches the clearance limit and report leaving the clearance limit.

18. With the help of suitable diagram describe simple approach lighting system for CAT -1 approach runway

Ans: A variety of approach lighting systems based on the centre line and cross bar concept, is in use at aerodromes. These systems range from the simple low intensity centre line and cross bar - intended to serve visual runways at night only, to the more complex Calvert System comprising centre line and 5 cross bars - shown at Figure 1.3 and 1.4 - for day and night use on ILS equipped runways. Simple approach lighting systems normally commence 500 m prior to the runway threshold whilst the full Calvert System commences 900 m prior to runway threshold. Where, because of the geography of the approach, it is not possible to install a full system, a shortened system is employed and the Runway Visual Range (RVR) minima associated with the instrument approach procedure



adjusted accordingly. Except where supplemented by red side barrettes as described below, approach lighting is white in colour.

NB: given here both diagram, according to the question use the diagram. For this ques, use first diagram.

A simple approach lighting system is a lighting system intended for a non-instrument or a non-precision approach runway. Standards for this system are not included in this chapter as there is no operational credit for such systems.

PRECISION APPROACH CATEGORY I LIGHTING SYSTEM

A precision approach Category I lighting system is to be provided to serve a Cat I precision approach runway.

Location : A precision approach Category I lighting system is to consist of a row of lights on the extended centre line of the runway extending, wherever practicable, over a distance of 900m prior to the threshold, with rows of lights forming 5 crossbars, as shown below.

Note 1: The installation of an approach lighting system of less than 900m in length may result in operational limitations on the use of the runway.

Note 2: Existing lights spaced in accordance with imperial measurements are deemed to comply with comparable metric measurements.



The lights forming the centreline are to be placed at longitudinal intervals of 30m with the innermost light located 30m from the threshold. Each centreline light position is to consist of a single light source in the innermost 300m of the centreline, two light sources in the central 300m of the centreline, and three light sources in the outer 300m of the centreline, to provide distance information.

The lights forming the centreline light positions in the central 300m and the outer 300m of the centreline are to be spaced at 1.5m apart.

The lights forming the 5 crossbars are to be placed at 150m, 300m, 450m 600m and 750m from the threshold. The lights forming each crossbar are to be as nearly as practicable in a horizontal straight line at right angles to, and bisected by, the line of the centreline lights. The lights of the crossbar are to be spaced so as to produce a linear effect, except that gaps may be left on each side of the centreline. The lights within each bar on either side of the centreline are to be spaced at 2.7m apart. The outer ends of the crossbars are to lie on two straight lines that converge to meet the runway centreline 300m from the threshold.

The system is to lie as nearly as practicable in the horizontal plane passing through the threshold, provided that:

(a) no object other than an ILS antenna is to protrude through the plane of the approach lights within a distance of 60m form the centreline of the system; and

(b) no light other than a light located within the central part of a crossbar, or a centreline light position, may be screened from an approaching aircraft.

Any ILS antenna protruding through the plane of the lights is to be treated as an obstacle and marked and lighted accordingly.

Characteristics

The centreline and crossbar lights of a precision approach Category I lighting system are to be fixed lights showing variable white.

The lights are to be in accordance with the specifications of Figures 1.

19. What are the separation standards for crossing tracks with reference to distance & time Ans: Longitudinal Separation Longitudinal separation shall be applied so that the spacing between the estimated positions of the aircraft being separated is never less than a prescribed minimum. Longitudinal separation between aircraft following the same or diverging tracks may be maintained by application of speed control. In applying a time- or distance-based longitudinal separation minimum between aircraft following the same track, care shall be exercised to ensure that the separation minimum will not be



infringed whenever the following aircraft is maintaining a higher air speed than the preceding aircraft. When aircraft are expected to reach minimum separation, speed control shall be applied to ensure that the required separation minimum is maintained. Longitudinal separation may be established by requiring aircraft to depart at a specified time, to arrive over a geographical location at a specified time, or to hold over a geographical location until a specified time. For the purpose of application of longitudinal separation, the terms same track, reciprocal tracks and crossing tracks shall have the following meanings: Crossing Tracks Intersecting tracks or portions thereof other than those specified in paragraphs 2 and 3 of this chapter.

Longitudinal Separation Based On Time Time-based separation applied may be based on position information and estimates derived from voice reports, CPDLC or ADS. Crossing Track - Same Level Or Climbing And Descending Where lateral separation is not provided, vertical separation shall be provided: a) For at least 10 minutes before the second aircraft estimates the crossing point; and b) For at least 10 minutes after the time the first aircraft past the crossing point.

Longitudinal Separation Based on Distance Separation shall be established by maintaining not less than specified distance(s) between aircraft positions as reported by reference to DME in conjunction with other appropriate navigation aids. Direct controller-pilot communication shall be maintained while such separation is used. Where the term “on track” is used in the provisions relating to the application of longitudinal separation minima using DME, it means that the aircraft is flying either directly inbound to or directly outbound from the station.



Separation is to be checked by obtaining simultaneous DME readings from aircraft at frequent intervals to ensure that the minimum separation is established and will not be infringed. Crossing Track - Same Level or Climbing and Descending The distance between two aircraft shall be 20 NM, provided: a) Each aircraft utilises: i) The same “on-track” DME station when both aircraft are utilising DME, or ii) An “on track” DME station and a collocated common point when one aircraft is utilizing DME and the other is utilising GNSS, or iii) The same common point when both aircraft are utilising GNSS. b) Separation is checked by obtaining simultaneous DME readings from the aircraft at frequent intervals to ensure that the minimum will not be infringed; and c) Each aircraft reports the distance from the station located at the crossing point of the tracks and that the relative angle between the tracks is less than 90 degrees.

The distance between two aircraft shall be 10 NM, provided: a) The leading aircraft maintains a true airspeed of 20kts or more faster than the succeeding aircraft; and b) Each aircraft utilises: i) The same “on-track” DME station when both aircraft are utilising DME, or ii) An “on track” DME station and a collocated common point when one aircraft is utilizing DME and the other is utilising GNSS, or iii) The same common point when both aircraft are utilising GNSS. c) Separation is checked by obtaining simultaneous DME readings from the aircraft at such intervals as are necessary to ensure that the minimum is established and will not be infringed; and d) Each aircraft reports distance from the station located at the crossing point of the tracks and that the relative angle between the tracks is less than 90 degrees.



20. Explain the co-ordination procedure between radar control unit & Non – Radar control procedure at ATS unit

Ans: Radar control the term used to indicate that radar derived information is employed directly in the provision of air traffic control service:



Nov/Dec 2011 PART B

1. What are the four operating positions in a control tower and what are the duties assigned

to each? Ans: Control towers were established to provide for a safe, orderly, and expeditious flow of air traffic at an airport and in its vicinity. It is hard to miss the Control Tower, the tall building with the glass-enclosed cab on top. Each airport’s control tower is also known as Local Control. There are four major controller classifications at control towers:

Flight Data Controller Clearance Delivery Controller Ground Controller Local Controller

Controllers working in an airport’s control tower are rotated through each position during one work shift. Each of these positions has specific duties. Flight Data (FD) Controller The Flight Data Controller: Receives and relays IFR Departure clearances Operates the Flight Data Processing Equipment Relays weather and NOTAM Information Previously, the FD Controller managed in-range flights using “flight progress strips” of paper. Today, the paper strips have been effectively eliminated with electronic flight data displays (the User Request Evaluation Tool - URET). The Flight Data Controller is also responsible for the Automatic Terminal Information Service (ATIS) equipment. ATIS recordings are made every hour or more often if the weather changes. Clearance Delivery Controller The Clearance Delivery Controller is responsible for obtaining and relaying departure clearances to pilots. These departure clearances include the following information: • Aircraft Identification • Clearance limit • Departure Procedure • Route of flight • Altitude assigned • Departure frequency • Transponder code The Clearance Delivery Controller checks to see that the route indicated for the flight requested conforms to established preferential routes. If there are departure restrictions that would supersede the requested clearance, then the clearance delivery controller may temporarily amend the clearance. Ground Controller The Ground Controller is responsible for the ground movement of aircraft taxiing or vehicles operating on taxiways or inactive runways. The ground controller is responsible for and can issue clearances only to those aircraft and vehicles that can be seen by this controller. Runway Incursion prevention is a primary responsibility of the ground controller. In the year 2000 there were more than 400 runway incursions recorded. A runway incursion is the unauthorized entry of an aircraft or vehicle onto an active runway without the permission of the local controller. For a Ground Controller to issue a clearance for an aircraft or vehicle to cross an active runway, the ground controller must first gain permission from the local controller responsible for that runway.



Another major responsibility for the ground controller is protection of “critical areas”. These protected zones include localizer, glide slope and precision approach critical areas. The critical areas provide greater obstacle clearance during approaches. As the weather conditions change the size of the zone increases. For example, if the weather conditions give a ceiling of less than 800 feet with the landing aircraft between the outer marker and the runway, then taxiing aircraft and other ground vehicles must hold short of the designated critical areas until the aircraft has landed. For approaches by “heavies” with the ceiling less than 200 feet or with the Runway Visual Range (RVR) at 2,000 feet or less, the critical area expands to an even greater distance from the runway. The airport is responsible for determining size of the critical area and designating the affected runways and/or taxiways in their briefings. Local Controller The one major responsibility of the Local Controller is to provide separation between arriving and departing aircraft. Another major responsibility of the Local Controller is to safely sequence arrivals and departures. This controller also relays IFR clearances and taxi instructions. The Local Controller also issues takeoff and landing clearances and provides assistance to other flights flying through their local area. The FAA has clearly identified guidelines for keeping aircraft at a safe distance from each other. This is known as safe separation distance. According to the FARs, runway separation regulations describe the following 3 aircraft categories Category light-weight single-engine propeller driven aircraft Category II light-weight twin-engine aircraft weighing 12,500 pounds or less Category III everything else including high performance single-engine propeller airplanes, large multi-engine propeller aircraft and all turbine powered aircraft The FAA separation regulations also specify that departing aircraft may not take off from a runway unless: A landing aircraft has taxied clear of the runway, or A departing aircraft is airborne and is clear of the departure end of the runway or A departing aircraft has turned away from the departing runway But the regulations also say that the following aircraft can depart: If the takeoff separation is 3,000 feet and both aircraft are Category I If a Category II aircraft departs before a Category I aircraft If a Category II aircraft takes off after a Category I aircraft If both aircraft are Category II aircraft and the separation distance is 4,500 feet If either aircraft is a Category III aircraft and the separation distance is 6,000 feet In other words, during the Takeoff phase of flight a fast, large jetliner should never take off behind a much smaller and slower 2-seater aircraft until it is out of the way. A local controller can allow an aircraft in line for takeoff to "taxi in position and hold" on the runway while another aircraft is on its takeoff roll. For arriving aircraft similar separation standards apply. IFR flights use a standard instrument approach when arriving at an airport. VFR pilots follow a standard traffic pattern. The VFR traffic pattern is an established, standardized flight pattern. The separation regulations for arriving aircraft are similar to the departure regulations with added complications. Arriving aircraft have different speeds with higher speed aircraft overtaking other slower aircraft. Many aircraft have stall speeds higher than many other aircraft top speeds. The controllers must sequence and space all arriving aircraft in a dynamic system. A further complication is all aircraft produce wingtip vortices. Vortices are caused by the generation of lift from the wings. The vortices generated by a small aircraft are not nearly as troublesome as the vortices generated by a “heavy”. “Heavy aircraft” (aircraft weighing 255,000 pounds or more) and Boeing 757 aircraft, generate vortices with a strength of small tornadoes. Wingtip vortices generated by a large jetliner can cause tremendous turbulence for a much smaller aircraft if it is following too close behind. There has to be a greater separation in distance and time



when a “heavy” is in the traffic mix. Wingtip vortices can cause problems no matter the size of any of the aircraft if safe separation is not maintained. It is the local controller who determines the spacing and separation of both departing and landing aircraft. Wingtip vortices and safe separation are extremely important to the pilots of these aircraft and the local controller assisting them.

2. Explain various separation techniques. Ans: Separation: Separation of aircraft operating within controlled airspace is applied in accordance with the minima specified in ICAO PANS-RAC Doc 4444. Separation between aircraft operating in the vicinity of an aerodrome may be reduced by ATS units under the following circumstances: a) The controller has the aircraft concerned in sight and can ensure adequate separation; or b) Aircraft concerned are continuously visible to the pilots concerned and the pilots report that they can maintain their own separation; or c) the pilot of a following aircraft reports that he/she can keep the preceding aircraft continuously in sight and can maintain his/her own separation with the preceding aircraft. The pilot has the ultimate responsibility for ensuring appropriate separations and positioning of the aircraft in the terminal area to avoid the wake turbulence created by a preceding aircraft There are three sets of flight rules under which an aircraft can be flown:

Visual Flight Rules (VFR) Special Visual Flight Rules (SVFR) Instrument Flight Rules (IFR)

Public transport flights are almost exclusively operated under IFR, as this set of rules allows flight in regions of low visibility (e.g. cloud). On the other hand a large amount of private flying in light aircraft is done under VFR since this requires a lower level of flying skill on the part of the pilot, and meteorological conditions in which a pilot can see and avoid other aircraft. As its name suggests, SVFR is a special infrequently-used set of rules. For the purposes of separation, controllers consider SVFR to be the same as IFR. Airspace exists in seven classes, A to G, in decreasing order of air traffic control regulation. Classes A to E are controlled airspace and classes F and G are uncontrolled airspace. At one end of the scale in classes A and B airspace, all aircraft must be separated from each other. At the other end of the scale in class G airspace there is no requirement for any aircraft to be separated from each other. In the intermediate classes some aircraft are separated from each other depending on the flight rules under which the aircraft are operating. For example in class D airspace, IFR aircraft are separated from other IFR aircraft, but not from VFR aircraft, nor are VFR aircraft separated from each other. Vertical separation Between the surface and an altitude of 29,000 feet (8,800 m), no aircraft should come closer vertically than 300 metres or 1,000 feet (in those countries that express altitude in feet), unless some form of horizontal separation is provided. Above 29,000 feet (8,800 m) no aircraft shall come closer than 600 m (or 2,000 feet), except in airspace where Reduced Vertical Separation Minima (RVSM) can be applied. Horizontal separation If any two aircraft are separated by less than the vertical separation minimum, then some form of horizontal separation must exist. Procedural separation Procedural separation is separation based upon the position of the aircraft, based upon reports made by the pilots over the radio. It therefore does not necessarily require the use of radar to provide air traffic control using procedural separation minima. In procedural control, any period during which two aircraft are not vertically separated is said to be "level change". In some cases,



procedural separation minima are provided for use with radar assistance, however it is important not to get this mixed up with radar separation as in the former case the radar need not necessarily be certified for use for radar separation purposes, the separation is still procedural. Lateral separation Lateral separation minima are usually based upon the position of the aircraft as derived visually, from dead reckoning or internal navigation sources, or from radio navigation aids ('beacons').In the case of beacons, to be separated, the aircraft must be a certain distance from the beacon (measured by time or by DME) and their tracks to or from the beacon must diverge by a minimum angle. Other lateral separation may be defined by the geography of pre-determined routes, for example the North Atlantic Track system. Longitudinal separation If two aircraft are not laterally separated, and are following tracks within 45 degrees of each other (or the reciprocal), then they are said to be following the same route and some form of longitudinal separation must exist. Longitudinal separation can be based upon time or distance as measure by DME. The golden rule is the 10 minute rule: no two aircraft following the same route must come within 15 minutes flying time of each other. In areas with good nav-aid cover this reduces to 10 minutes; if the preceding aircraft is faster than the following one then this can be reduced further depending of the difference in speed. Aircraft whose tracks bisect at more than 45 degrees are said to be crossing, in this case longitudinal separation cannot be applied as it will not be very long before lateral separation will exist again. Radar separation Radar separation is applied by a controller observing that the radar returns from the two aircraft are a certain minimum horizontal distance away from each other, as observed on a suitably calibrated radar system. The actual distance used varies: 5 nmi (9 km) is common in en route airspace, 3 NM is common in terminal airspace at lower levels. On occasion 10 NM may be used, especially at long range or in regions of less reliable radar cover. By FAA Rules [2], when an aircraft is: 1. Less than 40 miles from the [radar] antenna, horizontal separation is 3 miles from obstructions or other aircraft. 2. 40 miles or more from the [radar] antenna, horizontal separation is 5 miles from obstructions or other aircraft. 3. Terminal Area For single sensor ASR-9 with Mode S, when less than 60 miles from the antenna, horizontal separation is 3 miles from other aircraft. Reduced separation In certain special cases, controllers may reduce separation below the usually required minima. In the vicinity of an aerodrome Aerodrome or "Tower" controllers work in tall towers with large windows allowing them, in good weather, to see the aircraft flying in the vicinity of the aerodrome, unless the aircraft is not in sight from the tower (e.g. a helicopter departing from a ramp area). Also, aircraft in the vicinity of an aerodrome tend to be flying at lower speeds. Therefore, if the aerodrome controller can see both aircraft, or both aircraft report that they can see each other, or a following aircraft reports that it can see the preceding one, controllers may reduce the standard separation to whatever is adequate to prevent a collision. RVSM: Reduced Vertical Separation Minima In certain airspace, between 29,000 and 41,000 feet (12,500 m), pairs of aircraft equipped with more modern altimeter and autopilot systems can be vertically separated by minimum of 1,000 feet (300 m) rather than the standard 2,000 feet (600 m). RVSM airspace encompasses Europe, North America, parts of Asia and Africa and both the Pacific and Atlantic oceans.



3. How do military and civilian ATC co-ordinate themselves? Ans: Civil-Military Cooperation:

1. There are numerous areas of interaction between the civilian departments and the defence authorities. Action is required as under to sort out the various issues: a. In order to meet the expanding requirements of civil air traffic there is an urgent need to widen the existing air corridors, provide them Uni-directional air corridors, to provide smooth flow of air traffic and thus enhance air safety. b. We have to optimize the utilization of restricted air space, by networking of radar and data systems, which should be acquired on the basis of mutual compatibility. c. Additional land is to be provided at civilian enclaves in military airports. Revenue from aeronautical charges at these airports deserves to be shared with the AAI, in order to compensate it for the capital investment it has made. d. Additional slots should be made available for civilian flights at military airports. 2. In order to ensure civil-military cooperation, coordination committee at the level of respective Ministries as well as at operational level will be energized. COORDINATION BETWEEN MILITARY ATHORITIES AND AIR TR AFFIC SERVICES: 1 Air traffic services units shall establish and maintain close cooperation with military authorities responsible for activities that may affect flights of civil aircraft. 2 Coordination of activities potentially hazardous to civil aircraft shall be effected in accordance with the paragraph given below as A 3 Arrangements shall be made to permit information relevant to the safe and expeditious conduct of flights of civil aircraft to be promptly exchanged between air traffic services units and appropriate military units. 3 Air traffic services units shall, either routinely or on request, in accordance with locally agreed procedures, provide appropriate military units with pertinent flight plan and other data concerning flights of civil aircraft. 4 Special procedures shall be established in order to ensure that: a) air traffic services units are notified if a military unit observes that an aircraft which is, or might be, a civil aircraft is approaching, or has entered, any area in which interception might become necessary; b) all possible efforts are made to confirm the identity of the aircraft and to provide it with the navigational guidance necessary to avoid the need for interception.

A- COORDINATION BETWEEN AERONAUTICAL NFORMATION SERVIC E (AIS) AND AIR TRAFFIC SERVICES (ATS) UNITS 1 To ensure that aeronautical information services units obtain information to enable them to provide up to-date preflight information and to meet the need for in-flight information, arrangements shall be made locally between aeronautical information services and ATS units responsible for AIS to report to the responsible AIS unit, with a minimum of delay: a) Information on aerodrome conditions;

b) The operational status of associated facilities, services and navigation aids within their area of responsibility;

c) The occurrence of volcanic activity observed by air traffic services personnel or reported by aircraft; and d) Any other information considered to be of operational significance. 2 Before introducing changes to the air navigation system, due account shall be taken by the services responsible for such changes of the time needed by the aeronautical information service for the preparation, production and issuance of relevant material for promulgation. To



ensure timely provision of the information to the aeronautical information service, close coordination between those services concerned is therefore required. 3 Of particular importance are changes to aeronautical information that affect charts and/or computer-based navigation systems which qualify to be notified by the Aeronautical Information Regulation and Control (AIRAC) system. The predetermined, internationally agreed AIRAC effective dates in addition to 14 days postage time shall be observed by the responsible air traffic services when submitting the raw information/data to aeronautical information services.

4. What is the purpose of holding pattern and what are the variables affect the size of holding pattern?

Ans: A holding pattern for instrument flight rules (IFR) aircraft is usually a racetrack pattern based on a holding fix. This fix can be a radio beacon such as a non-directional beacon (NDB) or VHF omni-directional range (VOR). The fix is the start of the first turn of the racetrack pattern. Aircraft will fly towards the fix, and once there will enter a predefined racetrack pattern. A standard holding pattern uses right-hand turns and takes approximately 4 minutes to complete (one minute for each 180 degree turn, and two one-minute straight ahead sections). Deviations from this pattern can happen if long delays are expected; longer legs (usually two or three minutes) may be used, or aircraft with distance measuring equipment (DME) may be assigned patterns with legs defined in nautical miles rather than minutes. Less frequent turns are more comfortable for passengers and crew. Additionally, left-hand turns may be assigned to some holding patterns if there are airspace restrictions nearby. In the absence of a radio beacon, the holding fix can be any fixed point in the air, and can be created using two crossing VHF omni-directional range radials (also called intersection), or it can be at a specific distance from a VOR using a coupled distance measuring equipment. When DME is used, the inbound turn of the racetrack may be permanently defined by distance limits rather than in minutes. Furthermore, in appropriately equipped aircraft, GPS waypoints may be used to define the holding pattern, eliminating the need for ground-based navigational aids entirely. A hold for visual flight rules aircraft is usually a (smaller) racetrack pattern flown over something easily recognizable on the ground, such as a bridge, highway intersection or lake.

Purpose: The primary use of a holding pattern is delaying aircraft that have arrived at their destination but cannot land yet because of traffic congestion, poor weather, or runway unavailability (for instance, during snow removal). Several aircraft may fly the same holding pattern at the same time, separated vertically by 1,000 feet or more. This is generally described as a stack or holding stack. As a rule, new arrivals will be added at the top. The aircraft at the bottom of the stack will be taken out and allowed to make an approach first, after which all aircraft in the



stack move down one level, and so on. Air traffic control (ATC) will control the whole process, in some cases using a dedicated controller (called a stack controller) for each individual pattern. One airport may have several holding patterns; depending on where aircraft arrive from or which runway is in use, or because of vertical airspace limitations. Since an aircraft with an emergency has priority over all other air traffic, they will always be allowed to bypass the holding pattern and go directly to the airport (if possible). Obviously, this causes more delays for other aircraft already in the stack. The Variables Affect the Size of Holding Pattern: DEVELOPMENT CONCEPT. Efficient and economical use of airspace requires standardization of aircraft entry and holding maneuvers. Factors which affect aircraft during these maneuvers are incorporated in the criteria.

TURN EFFECT. Pilot procedures contained in the Aeronautical Information Manual (AIM) specify 30° of bank (or a standard rate turn, whichever requires the least bank) for entry and holding pattern turns. However, due to factors such as instrument precision, pilot technique, ballistic effect, etc., a constant 30° of bank is seldom achieved. To compensate for this, these criteria are based upon 25° of bank.

NAVIGATIONAL AID (NAVAID) GROUND AND AIRBORNE SYSTE M TOLERANCE.

Criteria in this chapter apply to conventional NAVAID's such as very high frequency (VHF) omni directional radio range (VOR), distance measuring equipment (DME), and/or non-directional radio beacon (NDB). These criteria contain allowances for:

a. Cone of ambiguity: related to altitude, and (1) System error: ± 5° (2) Aircraft Course Indicator: ± 10° for full instrument deflection. (3) Total tolerance of (1) and (2): 15°

b. Intersection disparity: related to system error and distance of the holding point from the furthest NAVAID. c. Overhead "to-from" error: 4°. d. Delay in recognizing and reacting to fix passage: 6 seconds for entry turn, applied in the direction most significant to protected airspace. EFFECT OF WIND. Analysis of winds recorded at various levels over a five-year period

led to the adoption of a scale of velocities beginning with 50 knots at 4,000' MSL and increasing at a rate of 3 knots for each additional 2,000' of altitude to a maximum of 120 knots.

FLIGHT PROCEDURES DEVELOPMENT. Flight procedures are developed to accommodate the performance capabilities of pertinent civil and military aircraft. The full size of the holding pattern shall be evaluated for obstacle clearance. No fix-end or outbound-end reduction is authorized.

APPLICATION IN THE AIR TRAFFICE CONTROL (ATC) SYSTE M. Holding airspace area dimensions were developed to permit use of all types of en route NAVAID's, reduction of holding airspace when optimum direction of entry is made, compatibility between patterns flown by reference to time and those flown by reference to DME, and selection/application of tailor-made airspace by furnishing several

FLYING A HOLDING PATTERN Many aircraft have a specific holding speed published by the manufacturer; this is a lower

speed at which the aircraft uses less fuel per hour than normal cruise speeds. A typical holding speed for transport category aircraft is 210 to 265 knots (491 km/h). Holding speeds are a function of aircraft weight at the point of holding. If possible, a holding pattern is flown with flaps and landing gear up to save fuel.

Entry procedures and accurate flying of the holding procedure are essential parts of IFR pilot training, and will always be tested on examination flights. Modern autopilots, coupled with flight management systems, can enter and fly holding patterns automatically.



ENTRY PROCEDURES The entry to a holding pattern is often the hardest part for a novice pilot to grasp, and

determining and executing the proper entry while simultaneously controlling the aircraft, navigating and communicating with ATC requires practice. There are three standard types of entries: direct, parallel, and offset (teardrop). The proper entry procedure is determined by the angle difference between the direction the aircraft flies to arrive at the beacon and the direction of the inbound leg of the holding pattern.

• A direct entry is performed exactly as it sounds: the aircraft flies directly to the holding fix, and immediately begins the first turn outbound.

• In a parallel entry, the aircraft flies to the holding fix, parallels the inbound course for one minute outbound, and then turns back, flies directly to the fix, and continues in the hold from there.

• In an offset or teardrop entry, the aircraft flies to the holding fix, turns into the protected area, flies for one minute, and then turns back inbound, proceeds to the fix and continues from there.

• Standard holding entry diagrams • Direct entry (Sector 3) • Parallel entry (Sector 1) • Teardrop entry (Sector 2)

•

The parallel and teardrop entry are mirrored in case of a left-hand holding pattern. Speed limits

Maximum holding speeds are established to keep aircraft within the protected holding area during their one-minute inbound and outbound legs. Timing corrections

To achieve a one-minute inbound leg, there are two key ways to modify timings: • Simple Method: If inbound leg is less than one minute, add the same number of seconds to

the outbound leg. If the inbound time is more than one minute, subtract the same number of seconds from the outbound leg.

o i.e. Inbound time is 0:55 --> Outbound time is 1:05 o i.e. Inbound time is 1:06 --> Outbound time is 0:54

• Ideal Method: Subtract 2/3 of the error (in seconds) for inbound legs more than one minute, and add 3/2 of the error (in seconds) for inbound legs of less than one minute.

o i.e. Inbound time is 0:55 --> Error is 5 seconds. Thus +3/2*5 = +7. 1:00+0:07=1:07. Fly 1:07 Outbound.

o i.e. Inbound time is 1:06 --> Error is 6 seconds. Thus (-2)/3*6 = (-4). 1:00-0:04=0:56. Fly 0:56 Outbound.

• For an initial gauge, add the headwind or subtract the tailwind component speed in knots. o i.e. Initial outbound with a tailwind component of 7 knots. Initial outbound 0:53. o i.e. Initial outbound with a headwind component of 20 knots. Initial outbound 1:20.



5. Describe the function of various components of Radar with a block diagram. Ans: Radar Principle The electronic principle on which radar operates is very similar to the principle of sound-wave reflection. If you shout in the direction of a sound-reflecting object (like a rocky canyon or cave), you will hear an echo. If you know the speed of sound in air, you can then estimate the distance and general direction of the object. The time required for an echo to return can be roughly converted to distance if the speed of sound is known. Radar uses electromagnetic energy pulses in much the same way. The radio-frequency (rf) energy is transmitted to and reflected from the reflecting object. A small portion of the reflected energy returns to the radar set. This returned energy is called an ECHO, just as it is in sound terminology. Radar sets use the echo to determine the direction and distance of the reflecting object. RAdio (Aim) Detecting And Ranging It refers to electronic equipment that detects the presence of objects by using reflected electromagnetic energy. Under some conditions a radar system can measure the direction, height, distance, course and speed of these objects. The frequency of electromagnetic energy used for radar is unaffected by darkness and also penetrates fog and clouds. This permits radar systems to determine the position of airplanes, ships, or other obstacles that are invisible to the naked eye because of distance, darkness, or weather. Modern radar can extract widely more information from a target's echo signal than its range. But the calculating of the range by measuring the delay time is one of its most important functions. Functions:

The following figure shows the operating principle of a primary radar set. The radar antenna illuminates the target with a microwave signal, which is then reflected and picked up by a receiving device. The electrical signal picked up by the receiving antenna is called echo or return. The radar signal is generated by a powerful transmitter and received by a highly sensitive receiver. All targets produce a diffuse reflection i.e. it is reflected in a wide number of directions. The reflected signal is also called scattering. Backscatter is the term given to reflections in the opposite direction to the incident rays. Radar signals can be displayed on the traditional plan position indicator (PPI) or other more advanced radar display systems. A PPI has a rotating vector with the radar at the origin, which indicates the pointing direction of the antenna and hence the bearing of targets.

Figure 1: Block diagram of a primary radar (interactive picture)



Transmitter The radar transmitter produces the short duration high-power RF pulses of energy that are into space by the antenna. Duplexer The duplexer alternately switches the antenna between the transmitter and receiver so that only one antenna need be used. This switching is necessary because the high-power pulses of the transmitter would destroy the receiver if energy were allowed to enter the receiver. Receiver The receivers amplify and demodulate the received RF-signals. The receiver provides video signals on the output. Radar Antenna The Antenna transfers the transmitter energy to signals in space with the required distribution and efficiency. This process is applied in an identical way on reception. Indicator The indicator should present to the observer a continuous, easily understandable, graphic picture of the relative position of radar targets. The radar screen (in this case a PPI-scope) displays the produced from the echo signals bright blibs. The longer the pulses were delayed by the runtime, the further away from the center of this radar scope they are displayed. The direction of the deflection on this screen is that in which the antenna is currently pointing.

6. How does the use of RADAR make the air traffic control system more efficient? Ans:

1. RADAR surveillance systems, such as primary surveillance radar (PSR), secondary surveillance radar (SSR) and automatic dependence surveillance – broadcast (ADSB) may be used either alone or in combination in the provision of air traffic services, including in the provision of separation between aircraft, provided:

a) Reliable coverage exists in the area; b) The probability of detection, the accuracy and the integrity of the ATS surveillance system(s) are satisfactory; and c) In the case of ADS-B, the availability of data from participating aircraft is adequate,

2. PSR systems should be used in circumstances where SSR and/or ADS-B alone would not meet the air traffic services requirements.

3. SSR system, especially those utilizing mono-pulse technique or having Mode S capability, may be used alone, including in the provision of separation between aircraft, provided;

a) The carriage of SSR transponders is mandatory within the area; and b) Identification is established and maintained.

4. ADS-B shall only be used for the provision of air traffic control service provided the quality of the information contained in the ADS-B message exceeds the values specified by the appropriate ATS authority.

5. The provision of ATS surveillance services shall be limited when position data quality degrades below a level specified by the appropriate ATS authority.

6. Where PSR and SSR are required to be used in combination, SSR alone may be used in the event of PSR failure to provide separation between identified transponder re-equipped aircraft, provided the accuracy of the SSR position indications has been verified by monitor equipment or other means.

7. The number of aircraft simultaneously provided with ATS surveillance services shall not exceed that which can safely be handled under the prevailing circumstances, taking into account:

a) The structural complexity of the control area or sector concerned; b) The functions to be performed within the control area or sector concerned;



c) Assessments of controller workloads, taking into account different aircraft capabilities, and sector capacity; and d) the degree of technical reliability and availability of the primary and back-up communications, navigation and surveillance system, both in the aircraft and on the ground.

8. The following types of radar services may be provided to aircraft operating within reliable radar coverage:

Type of radar service Class of airspace Radar control service D & E

Radar Advisory service F

Radar Flight information service G 9. Before providing radar service to an aircraft, radar identification shall be established and

the pilot informed. Thereafter, radar identification shall be maintained until termination of the radar service.

10. If radar identification is subsequently lost, the pilot shall be informed accordingly and, when applicable, appropriate instructions issued.

11. The provision of radar services requires that aircraft remain in direct two way communication with the unit providing the service. However radar separation may be provided between two radar identified aircraft even when only one of the aircraft is in direct communication with the radar unit.

12. In the event of an aircraft in or appearing to be in, any form of emergency ATC will provide all possible assistance, including the provision of radar service to the extent possible. USE OF SURVEILLANCE SYSTEM IN AIR TRAFFIC CONTROL S ERVICE :

1. The information provided by ATS surveillance systems and presented on a situation display may be used to perform the following functions in the provision of air traffic control service;

1 Provide ATS surveillance services in order to:- a) Improve airspace utilization; b) Reduce delays; c) Facilitate direct routings and more optimum flight profiles; d) Enhance safety 2. Provide vectoring to:- a) Departing aircraft for expeditious and efficient departure flow and expediting climb to cruising level b) Arriving aircraft for the purpose of expediting descent from cruising level and establishing an expeditious and efficient approach sequence. c) Aircraft for purpose of resolving potential conflict. d) Assist pilot in their navigation. 3. Provide separation and maintain normal traffic flow when an aircraft experiencing communication failure is within area of coverage. 4. Maintain flight path monitoring of air traffic 5. Maintain a watch on the progress of air traffic, in order to provide a procedural controller with: a) Improved position information regarding aircraft under control. b) Supplementary information regarding other traffic. c) Any significant deviations by aircraft from their assigned routing or level.

2. The position indication presented on a situation display may be used to perform the following additional functions in the provision of approach control service:

a) Provide vectoring of arriving traffic on to pilot-interpreted final approach aids;



b) Provide vectoring of arriving traffic to a point from which a visual approach can be completed; c) Provide vectoring of arriving traffic to a point from which a surveillance radar approach can be made; d) Provide flight path monitoring of other pilot-interpreted approaches; e) In accordance with prescribed procedures, conduct: surveillance radar approaches; f) Provide separation between:

i) Succeeding departing aircraft; ii) Succeeding arriving aircraft; and

iii) A departing aircraft and a succeeding arriving aircraft.

7. Write short notes on: (i) aerodrome reference code (ii) aerodrome elevation Ans: Aerodrome Reference Code:

The aerodrome facility reference code, also to be known as the aerodrome reference code, is a two-element, alpha-numeric notation (for example 1B, 3C) derived from the critical aeroplane for that aerodrome facility. The code number is based on the aeroplane reference field length and the code letter is based on the aeroplane wing span and the outer main gear wheel span. The aerodrome reference code provides a method of grouping aeroplanes with different characteristics (eg. wing span, outer main gear wheel span, approach speed and all-up mass) which behave similarly when landing, taking-off or taxying. As the aerodrome reference code notation is derived from aeroplane and not aerodrome characteristics, it applies to the individual aerodrome facilities (eg, runways and taxiways) and indicates their suitability for use by specific groups of aeroplanes. In many cases to determine the appropriate design standard for an aerodrome facility, it is necessary first to identify the aeroplanes for which the facility is intended, and then to determine the aerodrome reference code notation for the most critical of these aeroplanes. The particular standard for the facility is then related to the more demanding of the two criteria (the number or the letter) or to an appropriate combination of both.



At aerodromes with more than one runway, the runways are classified as either primary or secondary runways. The primary runway of an aerodrome is the runway used in preference to others whenever conditions permit. It is generally the longest runway and aligned closest to the direction of the prevailing wind. The other runways are classified as secondary runways.

Aerodrome and runway elevations 1 The aerodrome elevation and geoid undulation at the aerodrome elevation position shall be measured to the accuracy of one-half metre or foot and reported to the aeronautical information services authority. 2 For an aerodrome used by international civil aviation for non-precision approaches, the elevation and geoids undulation of each threshold, the elevation of the runway end and any significant high and low intermediate points along the runway shall be measured to the accuracy of one-half metre or foot and reported to the aeronautical information services authority. 3 For precision approach runway, the elevation and geoid undulation of the threshold, the elevation of the runway end and the highest elevation of the touchdown zone shall be measured to the accuracy of one-quarter metre or foot and reported to the aeronautical information services authority.

8. Explain the landing procedure with various lighting systems. Ans: A variety of approach lighting systems based on the centre line and cross bar concept, is in use at aerodromes. These systems range from the simple low intensity centre line and cross bar - intended to serve visual runways at night only, to the more complex Calvert System comprising centre line and 5 cross bars - shown at Figure 1.3 and 1.4 - for day and night use on ILS equipped runways. Simple approach lighting systems normally commence 500 m prior to the runway threshold whilst the full Calvert System commences 900 m prior to runway threshold. Where, because of the geography of the approach, it is not possible to install a full system, a shortened system is employed and the Runway Visual Range (RVR) minima associated with the instrument approach procedure adjusted accordingly. Except where supplemented by red side barrettes as described below, approach lighting is white in colour.



NB: given here both diagram, according to the question use the diagram. For this ques, use first diagram.

A simple approach lighting system is a lighting system intended for a non-instrument or a non-precision approach runway. Standards for this system are not included in this chapter as there is no operational credit for such systems.

PRECISION APPROACH CATEGORY I LIGHTING SYSTEM

A precision approach Category I lighting system is to be provided to serve a Cat I precision approach runway.

Location: A precision approach Category I lighting system is to consist of a row of lights on the extended centre line of the runway extending, wherever practicable, over a distance of 900m prior to the threshold, with rows of lights forming 5 crossbars, as shown below.

Note 1: The installation of an approach lighting system of less than 900m in length may result in operational limitations on the use of the runway.

Note 2: Existing lights spaced in accordance with imperial measurements are deemed to comply with comparable metric measurements.

The lights forming the centre line are to be placed at longitudinal intervals of 30m with the innermost light located 30m from the threshold. Each centre line light position is to consist of a single light source in the innermost 300m of the centre line, two light sources in the central 300m of the centre line, and three light sources in the outer 300m of the centre line, to provide distance information.

The lights forming the centre line light positions in the central 300m and the outer 300m of the centre line are to be spaced at 1.5m apart.

The lights forming the 5 crossbars are to be placed at 150m, 300m, 450m 600m and 750m from the threshold. The lights forming each crossbar are to be as nearly as practicable in a



horizontal straight line at right angles to, and bisected by, the line of the centre line lights. The lights of the crossbar are to be spaced so as to produce a linear effect, except that gaps may be left on each side of the centre line. The lights within each bar on either side of the centre line are to be spaced at 2.7m apart. The outer ends of the crossbars are to lie on two straight lines that converge to meet the runway centre line 300m from the threshold.

The system is to lie as nearly as practicable in the horizontal plane passing through the threshold, provided that: (a) no object other than an ILS antenna is to protrude through the plane of the approach

lights within a distance of 60m form the centre line of the system; and (b) No light other than a light located within the central part of a crossbar, or a centre line

light position, may be screened from an approaching aircraft. Any ILS antenna protruding through the plane of the lights is to be treated as an obstacle and marked and lighted accordingly. Characteristics The centre line and crossbar lights of a precision approach Category I lighting system are to be fixed lights showing variable white.

The lights are to be in accordance with the specifications of Figures 1. VISUAL APPROACH SLOPE INDICATOR SYSTEMS A visual approach slope indicator system shall be provided to serve the approach to a runway,

whether or not the runway is served by electronic approach slope guidance, where one of the following applies:

(a) The runway is regularly used by jet-propelled aero planes engaged in air transport operations; or

(b) CASA directs that visual approach slope guidance be provided, because it has determined that such a visual aid is required for the safe operation of aircraft.

In making a determination that visual approach slope guidance is required, CASA will take into account the following:

(a) The runway is frequently used by other jet-propelled aero planes, or other aero planes with similar approach guidance requirements;

(b) The pilot of any type of aero plane may have difficulty in judging the approach due to: (i) Inadequate visual guidance such as is experienced during an approach over water

or featureless terrain by day or in the absence of sufficient extraneous lights in the approach area by night;

(ii) Misleading approach information such as that produced by deceptive surrounding terrain, runway slope, or unusual combinations of runway width, length and light spacing;

(iii) A displaced threshold;



(c) the presence of objects in the approach area may involve serious hazard if an aeroplane descends below the normal approach path, particularly if there are no non-visual or other visual aids to give warning of such objects;

(d) Physical conditions at either end of the runway present a serious hazard in the event of an aero plane undershooting or overrunning the runway; and

(e) Terrain or prevalent meteorological conditions are such that the aero plane may be subjected to unusual turbulence during approach.

CASA may direct that a visual approach slope indicator system be provided for temporary use only, for example due to a temporary displaced threshold, or during works in progress.

The standard installations must be: (a) At international aerodromes, T-VASIS, or double sided PAPI. Where this is

impracticable, an AT-VASIS or PAPI is acceptable; (b) At aerodromes other than international aerodromes, AT-VASIS or PAPI, except where

(c) below applies; (c) At aerodromes where CASA has determined that additional roll guidance is required,

and/or high system integrity is necessary, T-VASIS or double sided PAPI; and (d) AT-VASIS and PAPI must be installed on the left side of the runway, unless this is impracticable.

9. What are the physical characteristics of primary, secondary and parallel runways? Ans: Physical characteristics of primary, secondary and parallel runways: Actual length of runways Primary runway: Except as provided in Runways with stop ways or clearways, the actual runway length to be provided for a primary runway shall be adequate to meet the operational requirements of the aero planes for which the runway is intended and shall be not less than the longest length determined by applying the corrections for local conditions to the operations and performance characteristics of the relevant aero planes. Secondary runway: The length of a secondary runway shall be determined similarly to primary runways except that it needs only to be adequate for those aero planes which require to use that secondary runway in addition to the other runway or runways in order to obtain a usability factor of at least 95 per cent. Runways with stop ways or clearways: Where a runway is associated with a stop way or clearway, an actual runway length less than that resulting from application of Primary or Secondary runway, as appropriate, may be considered satisfactory, but in such a case any combination of runway, stop way and clearway provided shall permit compliance with the operational requirements for take-off and landing of the aero planes the runway is intended to serve. Width of runways The width of a runway shall be not less than the appropriate dimension specified in the following tabulation:



a. The width of a precision approach runway shall be not less than 30 m where the code number is 1 or 2. Minimum distance between parallel runways Where parallel non-instrument runways are intended for simultaneous use, the minimum distance between their centre lines shall be: C 210 m where the higher code number is 3 or 4; C 150 m where the higher code number is 2; and C 120 m where the higher code number is 1. Where parallel instrument runways are intended for simultaneous use subject to conditions specified in the ICAO PANS-RAC (Doc 4444) and the PANS-OPS (Doc 8168), Volume I, the minimum distance between their centre lines shall be: C 1 035 m for independent parallel approaches; C 915 m for dependent parallel approaches; C 760 m for independent parallel departures; C 760 m for segregated parallel operations; Except that: a) For segregated parallel operations the specified minimum distances: 1) may be decreased by 30 m for each 150 m that the arrival runway is staggered toward the arriving aircraft, to a minimum of 300 m; and 2) Shall be increased by 30 m for each 150 m that the arrival runway is staggered away from the arriving aircraft; b) for independent parallel approaches, combinations of minimum distances and associated conditions other than those specified in the ICAO PANS-RAC (Doc 4444) may be applied when it is determined that such combinations would not adversely affect the safety of aircraft operations. Slopes on runways: Longitudinal slopes The slope computed by dividing the difference between the maximum and minimum elevation along the runway centre line by the runway length shall not exceed:

a) 1 per cent where the code number is 3 or 4; and b) 2 per cent where the code number is 1 or 2.

The longitudinal slope along any portion of the runway shall not exceed: a) 1.25 per cent where the code number is 4, except that for the first and last quarter of the length of the runway the longitudinal slope should not exceed 0.8 per cent; b) 1.5 per cent where the code number is 3, except that for the first and last quarter of the length of a precision approach runway category II or III the longitudinal slope should not exceed 0.8 percent; and c) 2 per cent where the code number is 1 or 2.

Longitudinal slope changes Where slope changes cannot be avoided, a slope change between two consecutive slopes shall not exceed: a) 1.5 per cent where the code number is 3 or 4; and b) 2 per cent where the code number is 1 or 2. The transition from one slope to another shall be accomplished by a curved surface with a rate of change not exceeding: a) 0.1 per cent per 30 m (minimum radius of curvature of 30 000 m) where the code number is 4; b) 0.2 per cent per 30 m (minimum radius of curvature of 15 000 m) where the code number is 3; and c) 0.4 per cent per 30 m (minimum radius of curvature of 7 500 m) where the code number is 1 or 2.



Sight distance Where slope changes cannot be avoided, they shall be such that there will be an unobstructed line of sight from; a) any point 3 m above a runway to all other points 3 m above the runway within a distance of at least half the length of the runway where the code letter is C, D, E or F; b) any point 2 m above a runway to all other points 2 m above the runway within a distance of at least half the length of the runway where the code letter is B; and c) any point 1.5 m above a runway to all other points 1.5 m above the runway within a distance of at least half the length of the runway where the code letter is A. Distance between slope changes Undulations or appreciable changes in slopes located close together along a runway shall be avoided. The distance between the points of intersection of two successive curves shall not be less than: a) The sum of the absolute numerical values of the corresponding slope changes multiplied by the appropriate value as follows: – 30 000 m where the code number is 4; – 15 000 m where the code number is 3; and – 5 000 m where the code number is 1 or 2; or b) 45 m; whichever is greater. Transverse slopes To promote the most rapid drainage of water, the runway surface should, if practicable, be cambered except where a single cross fall from high to low in the direction of the wind most frequently associated with rain would ensure rapid drainage. The transverse slope should ideally be: – 1.5 per cent when the code letter is C, D, E or F; and – 2 per cent when the code letter is A or B; But in any event should not exceed 1.5 per cent or 2 per cent, as applicable, nor be less than 1 per cent except at runway or taxiway intersections where flatter slopes may be necessary. For a cambered surface the transverse slope on each side of the centre line should be symmetrical. The transverse slope shall be substantially the same throughout the length of a runway except at an intersection with another runway or a taxiway where an even transition shall be provided taking account of the need for adequate drainage. Distance between slope changes Undulations or appreciable changes in slopes located close together along a runway shall be avoided. The distance between the points of intersection of two successive curves shall not be less than: a) The sum of the absolute numerical values of the corresponding slope changes multiplied by the appropriate value as follows: – 30 000 m where the code number is 4; – 15 000 m where the code number is 3; and – 5 000 m where the code number is 1 or 2; or b) 45 m; whichever is greater. Strength of runways A runway shall be capable of withstanding the traffic of aeroplanes the runway is intended to serve. Surface of runways The surface of a runway shall be constructed without irregularities that would result in loss in friction characteristics or otherwise adversely affect the take-off or landing of an aeroplane. The surface of a paved runway shall be so constructed as to provide good friction characteristics when the runway is wet.



Measurements of the friction characteristics of a new or resurfaced runway shall be made with a continuous friction measuring device using self-wetting features in order to assure that the design objectives with respect to its friction characteristics have been achieved. The average surface texture depth of a new surface should be not less than 1.0 mm. When the surface is grooved or scored, the grooves or scorings should be either perpendicular to the runway centre line or parallel to non-perpendicular transverse joints, where applicable.

10. What are the visual aids used for obstacles, emergency services and signal area? Ans: Visual Aids Used For Obstacles: A fixed obstacle that extends above a take-off climb surface within 3 000 m of the inner edge of the take-off climb surface should be marked and Fixed obstacles that extend above an approach or transitional surface within 3 000 m of the inner edge of the approach surface shall be marked and, if the runway is used at night, lighted, except that: a) Such marking and lighting may be omitted when the obstacle is shielded by another fixed obstacle; b) The marking may be omitted when the obstacle is lighted by medium-intensity obstacle lights, Type A, by day and its height above the level of the surrounding ground does not exceed 150 m; c) The marking may be omitted when the obstacle is lighted by high-intensity obstacle lights by day; and d) The lighting may be omitted where the obstacle is a lighthouse and an aeronautical study indicates the lighthouse light to be sufficient. A fixed obstacle above a horizontal surface should be marked and, if the aerodrome is used at night, lighted except that: a) Such marking and lighting may be omitted when: 1) The obstacle is shielded by another fixed obstacle; or 2) For a circuit extensively obstructed by immovable objects or terrain, procedures have been established to ensure safe vertical clearance below prescribed flight paths; or 3) An aeronautical study shows the obstacle not to be of operational significance; b) The marking may be omitted when the obstacle is lighted by medium-intensity obstacle lights, Type A, by day and its height above the level of the surrounding ground does not exceed 150 m; c) The marking may be omitted when the obstacle is lighted by high-intensity obstacle lights by day; and d) The lighting may be omitted where the obstacle is a lighthouse and an aeronautical study indicates the lighthouse light to be sufficient. A fixed object that extends above an obstacle protection surface shall be marked and, if the runway is used at night, lighted. Vehicles and other mobile objects, excluding aircraft, on the movement area of an aerodrome are obstacles and shall be marked and, if the vehicles and aerodrome are used at night or in conditions of low visibility, lighted, except that aircraft servicing equipment and vehicles used only on aprons may be exempt. Elevated aeronautical ground lights within the movement area shall be marked so as to be conspicuous by day. Obstacle lights shall not be installed on elevated ground lights or signs in the movement area. Use of colours An object should be coloured to show a chequered pattern if it has essentially unbroken surfaces and its projection on any vertical plane equals orexceeds 4.5 m in both dimensions. The pattern should consist of rectangles of not less than 1.5 m and not more than 3 m on a side, the corners being of the darker colour. The colours of the pattern should contrast each with the other



and with the background against which they will be seen. Orange and white or alternatively red and white should be used, except where such colours merge with the background. (See Figure 6-1.) An object should be coloured to show alternating contrasting bands if: a) it has essentially unbroken surfaces and has one dimension, horizontal or vertical, greater than 1.5 m, and the other dimension, horizontal or vertical, less than 4.5 m; or b) it is of skeletal type with either a vertical or a horizontal dimension greater than 1.5 m.

Use of flags Flags used to mark objects shall be displayed around, on top of, or around the highest edge of, the object. When flags are used to mark extensive objects or groups of closely spaced objects, they shall be displayed at least every 15 m. Flags shall not increase the hazard presented by the object they mark. Flags used to mark fixed objects shall not be less than 0.6 m square and flags used to mark mobile objects, not less than 0.9 m square. Flags used to mark fixed objects should be orange in colour or a combination of two triangular sections, one orange and the other white, or one red and the other white, except that where such colours merge with the background, other conspicuous colours should be used. Flags used to mark mobile objects shall consist of a chequered pattern, each square having sides of not less than 0.3 m. The colours of the pattern shall contrast each with the other and with the background against which they will be seen. Orange and white or alternatively red and white shall be used, except where such colours merge with the background. Lighting of objects- Use of obstacle lights The presence of objects which must be lighted, as specified in 6.1, shall be indicated by low-, medium- or high-intensity obstacle lights, or a combination of such lights. Low-intensity obstacle lights, Type A or B, should be used where the object is a less extensive one and its height above the surrounding ground is less than 45 m. Where the use of low-intensity obstacle lights, Type A or B, would be inadequate or an early special warning is required, then medium- or high-intensity obstacle lights should be used. Low-intensity obstacle lights, Type C, shall be displayed on vehicles and other mobile objects excluding aircraft. Low-intensity obstacle lights, Type D, shall be displayed on follow-me vehicles. Low-intensity obstacle lights, Type B, should be used either alone or in combination with medium-intensity obstacle lights, Type B, in accordance with Medium-intensity obstacle lights, Type A, B or C, should be used where the object is an extensive one or its height above the level of the surrounding ground is greater than 45 m. Medium-intensity obstacle lights, Types A and C, should be used alone, whereas medium intensity obstacle lights, Type B, should be used either alone or in combination with low-intensity obstacle lights, Type B.



High-intensity obstacle lights, Type A, should be used to indicate the presence of an object if its height above the level of the surrounding ground exceeds 150 m and an aeronautical study indicates such lights to be essential for the recognition of the object by day. High-intensity obstacle lights, Type B, should be used to indicate the presence of a tower supporting overhead wires, cables, etc., VISUAL AIDS FOR NAVIGATION (INDICATORS AND SIGNALLI NG DEVICES) Wind direction indicator (a) An aerodrome should be equipped with a sufficient number of wind direction indicators in order to provide wind information to the pilot during approach and take-off. (b) Location: Each wind direction indicator should be located so that at least one wind direction indicator is visible from aircraft in flight, during approach or on the movement area before take-off, and in such a way as to be free from the effects of air disturbances caused by nearby objects. (c) Characteristics: (1) Each wind direction indicator should be in the form of a truncated cone made of fabric and should have a length of not less than 3.6 m and a diameter, at the larger end, of not less than 0.9 m. (2) It should be constructed so that it gives a clear indication of the direction of the surface wind and a general indication of the wind speed. (3) The colour or colours should be so selected as to make the wind direction indicator clearly visible and understandable from a height of at least 300 m, having regard to background: (i) Where practicable, a single colour should be used. (ii) Where a combination of two colours is required to give adequate conspicuity against changing backgrounds, they should be arranged in five alternate bands, the first and last bands being the darker colour. (d) Night conditions: Provision should be made for illuminating a sufficient number of wind indicators at an aerodrome intended for use at night. Landing direction indicator (a) Location: Where provided, a landing direction indicator should be located in a conspicuous place on the aerodrome. (b) Characteristics: (1) The landing direction indicator should be in the form of a ‘T’. (2) The shape and minimum dimensions of a landing ‘T’ should be as shown in Figure K-1. (3) The colour of the landing ‘T’ should be either white or orange, the choice being dependent on the colour that contrasts best with the background against which the indicator will be viewed. (4) Where used at night, the landing ‘T’ should either be illuminated or outlined by white lights. Signal panels and signal area (a) Applicability: A signal area should be provided when visual ground signals are used to communicate with aircraft in flight. (b) Location: The signal area should be located so as to be visible for all angles of azimuth above an angle of 10° above the horizontal when viewed from a height of 300 m. (c) Characteristics: (1) The signal area should be an even horizontal surface at least 9 m square. (2) The colour of the signal area should be chosen to contrast with the colours of the signal panels used, and it should be surrounded by a white border not less than 0.3 m wide. Location of signal area: A signal area need only be provided when it is intended to use visual ground signals to communicate with aircraft in flight. Such signals may be needed when the aerodrome does not have an aerodrome control tower or an aerodrome flight information service unit, or when the aerodrome is used by aero planes not equipped with a radio. Characteristics of signal area: The signal area should be constructed of cement concrete reinforced with an adequate quantity of steel to avoid cracks resulting from unequal settlement. The top surface should be finished smooth with a steel trowel and coated with paint of appropriate



colour. The colour of the signal area should be chosen to contrast with the colours of the signal panels to be displayed thereon. VISUAL AIDS FOR EMERGENCY SERVICES? Stopway Lighting Where stopway is provided at the end of a runway, the declared stop way is delineated by red edge and end lighting as illustrated in Figure 1.5 showing ONLY in the direction of landing. A stopway is provided for emergency use only and is not normally suitable for routine use. Lighting Fixed obstacles of 45 m or less in height, width and length are normally lit by a single steady red light placed at the highest practicable point; those obstacles of greater size are normally provided with additional red lights in order to outline the extent of the obstruction. Surface obstructions and unserviceable parts of the movement area are normally delineated by portable red lights. Mobile obstacles such as vehicles and equipment frequently employed on the movement area normally display a yellow flashing light except that emergency service vehicles responding to an incident display flashing blue lights. Marshalling:



Apr/May 2010 PART B

1. (i) Enumerate various ATC aids. Ans: The following are the various ATC aids:

1. Radio and Navigation Aids 2. Airport Lighting Aids (ALS) 3. Airport Visual Aids 4. Air Navigation and Obstruction Lighting Aids 5. Airport Marking Aids and Signs 6. Fitness for Flight 7. Flight Safety 8. Emergency services (ii) Briefly discuss the various parts of ATC services

Ans: Air Traffic Control services: A generic term meaning area control service, approach control service or aerodrome control service. The air traffic services comprise of three services identified as follows: 1. Air traffic control service � Area control service � Approach control service � Aerodrome control service 2. Flight information service 3. Alerting service

Area Control Service: The provision of air traffic control service for controlled flights, except for those parts of such flights which are under the jurisdiction of Approach Control or Aerodrome Control to accomplish following objectives: a) Prevent collisions between aircraft b) Expedite and maintain an orderly flow of air traffic Approach control service: The provision of air traffic control service for those parts of controlled flights associated with arrival or departure. Aerodrome control service: The provision of air traffic control service for aerodrome traffic, except for those parts of flights which are under the jurisdiction Approach Control. Provision of air traffic control service: The parts of air traffic control service, shall be provided by the various units as follows: Area control service Area control service shall be provided: a) By an area control centre (ACC); or b) By the unit providing approach control service in a control zone or in a control area of limited extent which is designated primarily for the provision of approach control service, when no ACC is established Approach control service Approach control service shall be provided: a) By an aerodrome control tower or an ACC, when it is necessary or desirable to combine under the responsibility of one unit the functions of the approach control service and those of the aerodrome control service or the area control Service. b) By an approach control unit, when it is established as a separate unit.



Aerodrome control service - Aerodrome control service shall be provided by an aerodrome control tower.

Operation of air traffic control service: In order to provide air traffic control service, an air traffic control unit shall: a) Be provided with information on the intended movement of each aircraft, or variations there from, and with current information on the actual progress of each aircraft b) Determine from the information received, the relative positions of known aircraft to each other c) Issue clearances and information for the purpose of preventing collision between aircraft under its control and of expediting and maintaining an orderly flow of traffic; d) Coordinate clearances as necessary with other units: 1) Whenever an aircraft might otherwise conflict with traffic operated under the control of such other units 2) Before transferring control of an aircraft to such other units. e) Information on aircraft movements, together with a record of air Traffic control clearances issued to such aircraft, shall be so displayed as to permit ready analysis in order to maintain an efficient flow of air traffic with adequate separation between aircraft. Explanation: Area Control Service:

En-route air traffic controllers work in facilities called Area Control Centers, each of which is commonly referred to as a "Center". The United States uses the equivalent term Air Route Traffic Control Center (ARTCC). Each center is responsible for many thousands of square miles of airspace (known as a Flight Information Region) and for the airports within that airspace. Centers control IFR aircraft from the time they depart from an airport or terminal area's airspace to the time they arrive at another airport or terminal area's airspace. Centers may also "pick up" VFR aircraft that are already airborne and integrate them into the IFR system. These aircraft must, however, remain VFR until the Center provides a clearance. Center controllers are responsible for climbing the aircraft to their requested altitude while, at the same time, ensuring that the aircraft is properly separated from all other aircraft in the immediate area. Additionally, the aircraft must be placed in a flow consistent with the aircraft's route of flight. As an aircraft reaches the boundary of a Center's control area it is "handed off" or "handed over" to the next Area Control Center. In some cases this "hand-off" process involves a transfer of identification and details between controllers so that air traffic control services can be provided in a seamless manner; in other cases local agreements may allow "silent handovers" such that the receiving center does not require any co-ordination if traffic is presented in an agreed manner. After the hand-off, the aircraft is given a frequency change and begins talking to the next controller. This process continues until the aircraft is handed off to a terminal controller ("approach"). Approach and terminal control: Many airports have a radar control facility that is associated with the airport. In most countries, this is referred to as Terminal Control; in the U.S., it is referred to as a TRACON (Terminal Radar Approach Control.) While every airport varies, terminal controllers usually handle traffic in a 30-to-50-nautical-mile (56 to 93 km) radius from the airport. Where there are many busy airports close together, one consolidated Terminal Control Center may service all the airports. The airspace boundaries and altitudes assigned to a Terminal Control Center, which vary widely from airport to airport, are based on factors such as traffic flows, neighboring airports and terrain. Terminal controllers are responsible for providing all ATC services within their airspace. Traffic flow is broadly divided into departures, arrivals, and over flights. As aircraft move in and out of the terminal airspace, they are handed off to the next appropriate control facility (a control tower, an en-route control facility, or a bordering terminal or approach control). Terminal control is responsible for ensuring that aircraft are at an appropriate altitude when they are handed off, and that aircraft arrive at a suitable rate for landing.



Not all airports have a radar approach or terminal control available. In this case, the en-route center or a neighboring terminal or approach control may co-ordinate directly with the tower on the airport and vector inbound aircraft to a position from where they can land visually. At some of these airports, the tower may provide a non-radar procedural approach service to arriving aircraft handed over from a radar unit before they are visual to land. Some units also have a dedicated approach unit which can provide the procedural approach service either all the time or for any periods of radar outage for any reason

2. Write short notes on:

(i) Area control service (6) Ans: Area control service: Air Traffic Control service for controlled flights in control areas. In air traffic control, an Area Control Center (ACC), also known as a Center, is a facility responsible for controlling instrument flight rules aircraft en route in a particular volume of airspace (a Flight Information Region) at high altitudes between airport approaches and departures.

- A Center typically accepts traffic from, and ultimately passes traffic to, the control of a Terminal Control Center or of another Center.

- Most Centers are operated by the national governments of the countries in which they are located.

- The general operations of Centers worldwide, and the boundaries of the airspace each Center controls, are governed by the ICAO

The provision of air traffic control service for controlled flights, except for those parts of such flights which are under the jurisdiction of Approach Control or Aerodrome Control to accomplish following objectives:

a) Prevent collisions between aircraft; b) Expedite and maintain an orderly flow of air traffic;

Area control service shall be provided: a) By an area control centre (ACC); or b) By the unit providing approach control service in a control zone or in a control area of limited extent which is designated primarily for the provision of approach control service, when no ACC is established. En-route air traffic controllers work in facilities called Area Control Centers, each of which is commonly referred to as a "Center". The United States uses the equivalent term Air Route Traffic Control Center (ARTCC). Each center is responsible for many thousands of square miles of airspace (known as a Flight Information Region) and for the airports within that airspace. Centers control IFR aircraft from the time they depart from an airport or terminal area's airspace to the time they arrive at another airport or terminal area's airspace. Centers may also "pick up" VFR aircraft that are already airborne and integrate them into the IFR system. These aircraft must, however, remain VFR until the Center provides a clearance. Center controllers are responsible for climbing the aircraft to their requested altitude while, at the same time, ensuring that the aircraft is properly separated from all other aircraft in the immediate area. Additionally, the aircraft must be placed in a flow consistent with the aircraft's route of flight. As an aircraft reaches the boundary of a Center's control area it is "handed off" or "handed over" to the next Area Control Center. In some cases this "hand-off" process involves a transfer of identification and details between controllers so that air traffic control services can be provided in a seamless manner; in other cases local agreements may allow "silent handovers" such that the receiving center does not require any co-ordination if traffic is presented in an agreed manner. After the hand-off, the aircraft is given a frequency change and begins talking to the next controller. This process continues until the aircraft is handed off to a terminal controller ("approach").



(ii) Runway lighting (4) Ans: Runway lighting includes such lights as edge, threshold, centre line, end, touchdown zone and wing bar lights. Runway lighting shall not be operated if the runway is not in use for landing, take-off or taxiing purposes. If the runway lighting is not operated continuously, lighting following a take-off shall be provided as specified below:

1. At aerodromes where ATC service is provided and where lights are centrally controlled, the lights of one runway shall remain lighted after take-off as long as is considered necessary for the return of the aircraft due to an emergency occurring during or immediately after take-off.

2. At aerodromes without ATC service or without centrally controlled lights, the lights of one runway shall remain lighted until such time as would be required to reactivate the lights in the likelihood of the departing aircraft returning for an emergency landing, and in any case not less than fifteen minutes after take-off.

3. Where obstacle lighting is operated simultaneously with runway lighting, particular care should be taken to ensure that it is not turned off until no longer required by the aircraft.

(iii) Flight plans (6)

Ans: Flight plan: Specified information provided to air traffic services units, relative to an intended flight or portion of a flight of an aircraft. Flight plans are documents filed by pilots or a Flight Dispatcher with the local Civil Aviation Authority prior to departure. Flight plan format is specified in the ICAO Doc 4444. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), the pilot's information, number of people on board and information about the aircraft itself. In most countries, flight plans are required for flights under IFR, but may be optional for flying VFR unless crossing international borders. Flight plans are highly recommended, especially when flying over inhospitable areas, such as water, as they provide a way of alerting rescuers if the flight is overdue. In the United States and Canada, when an aircraft is crossing the Air Defense Identification Zone (ADIZ), either an IFR or a special type of VFR flight plan called a DVFR flight plan must be filed (the "D" is for Defense). For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required, or for use by air traffic control when flying in a "Special Flight Rules Area". Contents of a Flight Plan: The ICAO FPL form shall be used for the purpose of completing a flight plan prior to departure or, in case the flight plan is submitted by telephone or tele-fax, the sequence of items in the flight plan form shall be strictly followed.

The following information shall be included in the flight plan: • Aircraft Identification • Flight rules and type of the flight • Number of aircraft, type of aircraft and wake turbulence category • Equipment • Departure aerodrome • Estimated off-block time • Cruising speed • Level • Route • Destination aerodrome and total estimated elapsed time



• Alternate aerodrome(s) • Endurance • Persons on board • Survival equipment • Pilot in command • Other information

If a flight is to cross a Finish state border, details of the entire flight to the destination aerodrome shall be submitted in the flight plan.

3. (i) Describe the procedure for the design of aerodrome. (8) Ans: Instrument approach procedures are designed to enable pilots to operate under Instrument Flight Rules (IFR) in Instrument Meteorological Conditions (IMC). The instrument approach procedures may direct aircraft to either descend down to circling minima and conduct a visual circling approach, or to a runway aligned position down to the runway landing minima and conduct a straight-in approach. Where the instrument approach procedure does not provide a straight-in approach, the runway is still classified as a non-instrument runway. Where the instrument procedure provides for a straight-in approach, the runway is classified as an instrument non-precision approach (NPA) runway. CASA strongly recommends that, where terrain permits, NPA procedures be provided as they enhance the safety and efficiency of aircraft operations. NPA procedures may use ground-based navigation aids, such as VOR, DME, NDB, etc. Increasingly, NPA procedures may also be designed using GPS. The use of GPS allows NPA procedures to be provided to aerodromes which have no access to ground-based navigation aids. Before a GPS NPA procedure is designed and published for a particular runway, the runway must meet the standards of a NPA runway. At some aerodromes there may be a cost involved in meeting these aerodrome standards. Whilst it is the prerogative of an aerodrome operator to determine whether his or her aerodrome should be upgraded, CASA strongly recommends that aerodrome operators avail themselves of the benefit of GPS technology. Request for NPA procedures may come from the Regional Airspace Planning and Advisory Committee (RAPAC), airline operators, aviation organizations, or aerodrome operators. Any proposal for, and design of, instrument approach procedures to a runway should only be made with the knowledge that the runway meets the appropriate aerodrome standards for NPA. Use of a runway which does not meet the appropriate aerodrome standards for NPA procedures could result in unsafe situations. Aerodrome standards: The standards for a NPA runway are different to the standards applicable to a non instrument runway in several aspects. These include: · Runway strip width ` · Approach OLS area and gradient · Availability of wind direction indicator near the threshold · Runway edge light spacing RUNWAY STRIP WIDTH: Many existing aerodromes have runways of 30 metres width contained within runway strips 90m to 150m wide. NPA procedures may be designed for runways with strip widths down to 90m provided the landing minima is adjusted in accordance with design requirements. The 90m strip width for NPA procedures are limited only to runways used by code 1, code 2 and up to code 3C aero planes. (Runways accommodating aero planes above code 3C (eg. B737) require a minimum graded runway strip width of 150m).



APPROACH OLS AREA AND GRADIENT The standard approach obstacle limitation surface (OLS) area for a NPA runway is considerably larger than a non-instrument runway. For code 1 and code 2 runways, the increases are not extensive. For a code 3 runway, the differences in the approach OLS area are: · Length - increases from 3000m to 15000m · Length of the inner edge - 150m.

· Side splay - increases from 10% to 15% · Approach gradient - down from 3.3% to 2% in the first section, 2.5% in the second section and horizontal for the third section. It should be noted that a code 3 runway also requires a 180m inner edge for the take-off surface, unless the runway is used only by aircraft with MTOW of less than 22700 kg and operating only in Visual Meteorological Conditions (VMC) during the day. To facilitate the introduction of NPA procedures without compromising aircraft safety, the following procedures may be used in dealing with obstacles within the approach OLS area: · Obstacles within 3000m of the inner edge of the approach surface (2500m for code 1 and 2 runways) are to be identified based on the applicable standard. · Objects previously not identified as obstacles, but which are classified as obstacles under the applicable standards, are to be referred to the relevant CASA Office for assessment of their impact upon aircraft operations and the need for marking and/or lighting of such obstacles. The obstacle data should also be provided directly to the procedure designer concerned · For areas beyond the 3000m, the procedure designer will obtain obstacle information from the national tall structure data bank and topographical maps. · Before a new or revised procedure is cleared by CASA for publication, the procedure will be flight validated to ensure that the required obstacle clearances are provided in the design. · The procedure designer will advise the aerodrome operator of the critical obstacles which govern the procedure minima, including allowances provided for the height of vegetation. · After the NPA straight-in procedure is published, the aerodrome operator will be required to monitor the approach OLS area and report any new obstacles or potential obstacles to the relevant CASA Office and to the Air services Procedure Design Section. AVAILABILITY OF A WIND DIRECTION INDICATOR NEAR TH E THRESHOLD Because the primary wind direction indicator (WDI) may not be visible from the approach minima, NPA runways require WDI near the threshold to provide surface wind information to pilots of landing aircraft. However, if another acceptable means of providing surface wind information is available, such as through an aerodrome weather information broadcast (AWIB), or an approved observer with a suitable communication link, the WDI requirement may be waived. Alternative arrangements for provision of surface wind information should be made with the relevant CASA Office if there is no WDI near the threshold. In addition, if a WDI is located near the threshold for NPA procedures purposes, and the NPA procedures are conducted at night, appropriate illumination of the WDI will have to be provided. RUNWAY EDGE LIGHT SPACING Existing runway edge lights for a non-instrument runway are normally spaced 90-100m apart. For a NPA runway, the lights should be spaced not more than 60m apart. However, NPA procedures may be provided for a runway with runway edge lights spaced at 90-100m apart, subject to the visibility minima being not less than 1.5 km and provided there are no extraneous lights around the aerodrome which may affect visual acquisition of the runway. Before NPA procedures are made available for night use, the lighting system will need to be checked. This hecking will generally be done as part of the NPA flight validation process, or by the relevant CASA Office. The aerodrome operator concerned will be consulted if there is a problem with the aerodrome lighting.



At aerodromes where NPA operations are conducted, aerodrome operators should ensure that time limited works are co-ordinated with arrival schedules to avoid risk to aircraft and persons on the ground. Currently, development works are being done in the global navigation satellite system (GNSS) with local or wide area augmentation to enhance the accuracy of the system. It is likely that in the near future Cat I precision approaches will be able to be conducted to runways with no Instrument Landing System (ILS). The aerodrome standards will need to be met to support these operations are more stringent, particularly in regard to runway and approach lighting. Aerodrome operators should bear this in mind if they are considering upgrading their aerodrome lighting systems. GPS NPA procedures may also be provided for helicopter landing sites (HLS), either on or off aerodromes. Currently, Australian standards do not specify NPA standards for HLS. In the interim, HLS meeting the NPA standards specified in ICAO Annex 14 Volume II are acceptable.

(ii) How are aerodrome classified in India. (8)

Ans: Airports Classification: In order to provide guide to airport designers for a reasonable amount of uniformity in airport landing facilities, design criteria have been prepared by ICAO and FAA through airport classifications. Aerodrome in India: With so many airports in India, traveling has become really convenient and easy. Over all these years, the Indian air industry has grown several folds and contributed in a big way to the tourism industry in India. Today there are a large number of airlines in India which have made it convenient for the travelers to reach their destinations easily. Most of the airports in India connect the Indian cities with the International cities. These are the international airports in India. The domestic airports in India link all the major corners of the country. Airports Authority of India (AAI) This Airports Authority of India which is under the control of Ministry of Civil Aviation is in charge of managing all the airports in India. The AAI is involved in the management and operation of 126 airports in India which include:

11 international airports 89 domestic airports 26 civil enclaves

Classification of Airports in India India has a total of 449 airports, out of which 92 airports and 28 civil enclaves in Defence airports offer flight services over the entire airspace of India and the neighboring oceanic areas. However, only 61 airports out of the total are permitted to be utilized by the airlines.

The Indian airports are categorized into following classifications: Indian airports are divided into 3 broad categories * Domestic * International and *Civil enclave There are two more categories in India * Customs Airport * Model Airport International Airports in India: These are declared as international airports and are available for scheduled international operations by Indian and foreign carriers. Presently, Mumbai, Delhi, Chennai, Calcutta and Thiruvananthapuram are in this category. The following airports link the major Indian cities to the international cities:



Amritsar International Airport , Indira Gandhi International Airport, New Delhi, Lokpriya Gopinath Bordolio International Airport, Guwahati, Sardar Vallabhbhai Patel International Airport, Ahmedabad, etc., Domestic Airports in India: All the Indian airports come under this category. Custom Airports in India: Custom Airports provide immigration and customs facilities for the international tourists. They also operate cargo charter flights. The custom airports in India are located at: Bangalore, Hyderabad, Ahmedabad, Calicut, Cochin, Goa, Varanasi, Patna, Agra, Jaipur, Amritsar, Tiruchirapally Model Airports in India: Indian Model Airports are the domestic airports with following features: Minimum 7500 feet length of runway Sufficient terminal capacity for handling aircraft of Airbus 320 type If required, can also handle limited international traffic The model airports in India are located in: Lucknow, Bhubaneshwar, Guwahati, Nagpur, Vadodara, Coimbatore, Imphal, Indore Civil Enclaves in Indian Defence Airports: 28 civil enclaves are included in the Defence airfields of India.

4. Briefly discuss the various requirements of an airport lighting systems and airport marking systems.

Ans: Refer Question No. 14 and 16 in Part B Ques and Ans.

5. Draw the typical layout of a small domestic’s terminal building and typical airport layout. Explain any two.

Ans: The layout of an airport is determined by five basic factors:

- The direction of prevailing winds (the major runways being oriented to the prevailing wind with a back up runway on a cross wind alignment)

- The size and number of terminal buildings - The ground transport system, especially the position of major access roads and

railways - Mandatory clearance dimensions between aircraft and buildings - Topography and geology

Small airports are usually a direct reflection of these spatial and organizational characteristics but as airports become larger a number of secondary factors come into play such as environmental controls, the geography of the surrounding region, and the capacity of the local road system. International airports, though their site layout is shaped primarily by wind direction, are increasingly constrained by such factors as community disturbance. As a consequence their growth and configuration rarely permit simple planning solution but are compromised by influences of a regional nature. Airport Types: There are three main types of airport:

- International airports serving over 20 million passengers a year - National airports serving between 2 and 20 million passengers a year - Regional airports serving up to 2 million passengers a year

Such a classification, based upon the level of traffic flow is a useful guide but by no means infallible. In countries such as Germany, which have a strong hub network of airports, some of the larger regional airports have passenger movements that approach international dimensions. Conversely in smaller countries with single national airports passenger movement below the norm for the classification may justify the inclusion of the airport in the top rank. If the level of passengers is a good is good general guide, other factors relevant to typological classification include:



- The split between domestic, national and international movements - The role of the airport as an international centre for aviation or as a distribution

hub - The scale of non airport facilities such as other transportation modes, hotels,

business and conference centres. Airport types are also a clue to security risks: International terrorism tends to target major international, not minor regional airports. The development of airport is more than the satisfying of aviation needs. No matter how lucrative or demanding these may be. Airports, whether international or regional in nature, need to develop the total business and this consists of aviation, retailing, land ownership and integrated transport opportunities. There are specific facilities for the business community: executives can jet in from different locations, have a meeting in one of the conference suites, and fly home. Business conferencing is an area of growth for regional airports, particularly those away from congested airspace locations.

Or (use any one diagram)

Fig: Typical Airport Layout



Fig: Typical design of a terminal building: showing the Departures (upper half of page) and Arrivals levels. 1. Departures Lounge. 2. Gates and jet bridges. 3. Security Clearance Gates. 4 Baggage Check-in. 5. Baggage Carousels Terminal Building: An airport terminal is a building at an airport where passengers transfer between ground transportation and the facilities that allow them to board and disembark from aircraft. Within the terminal, passengers purchase tickets, transfer their luggage, and go through security. The buildings that provide access to the airplanes (via gates) are typically called concourses. However, the terms "terminal" and "concourse" are sometimes used interchangeably, depending on the configuration of the airport. Smaller airports have one terminal while larger airports have several terminals and/or concourses. At small airports, the single terminal building typically serves all of the functions of a terminal and a concourse. Some larger airports have one terminal that is connected to multiple concourses via walkways, sky-bridges, or underground tunnels. Some larger airports have more than one terminal, each with one or more concourses. Still other larger airports have multiple terminals each of which incorporates the functions of a concourse. Airport Terminal Concept: The terminals at small airports have mostly been designed as centralized building that is where the processing of the passengers is done in one location rather than being distributed through several points in the terminal. The concept of the centralized terminal in combination wither piers, fingers or satellites is also used at larger airports. It provides easy orientation for the passengers through check in and security, optimum utilization of space and concentration of services in the terminal building. However, as the number of stands increases, the distance to the outlying stands exceeds the recommended walking distances and therefore it is necessary to provide transportation for the passengers from the central processing building to the gates together with an effective information system. A central building with a system of several parallel satellite piers interconnected by a transportation system makes an almost ideal solution for large airports if the space is available midfield ie., between parallel runways. It has a large capacity of both stands and peak hour passengers. It enables transfer of passengers to and from common travel areas without using the central building which then not required to handle these passengers. Therefore this design is convenient for the hub and spoke type of operation. It seems that it is possible to use central processing terminals up to about 30 mppa and 50or so gates, whether they have piers and moving walkways or have satellites and people movers.



6. (i) What are the ATC clearance requirements for airport (8) Ans: ATC clearance is an authorization for an aircraft to proceed under conditions specified by an air traffic control unit. Clearance may be prefixed by the words “taxi”, “take off”, “departure”, “en-route”, “approach” or “landing” to indicate the particular portion of flight to which the air traffic control clearance relates.

ATC clearances normally required to contain the following: a. Clearance Limit: The traffic clearance issued prior to departure will normally authorize flight to the airport of intended landing. Many airports and associated NAVAIDs are collocated with the same name and/or identifier, so care should be exercised to ensure a clear understanding of the clearance limit. When the clearance limit is the airport of intended landing, the clearance should contain the airport name followed by the word “airport.” Under certain conditions, a clearance limit may be a NAVAID or other fix. When the clearance limit is a NAVAID, intersection, or waypoint and the type is known, the clearance should contain type. Under certain conditions, at some locations a short-range clearance procedure is utilized whereby a clearance is issued to a fix within or just outside of the terminal area and pilots is advised of the frequency on which they will receive the long-range clearance direct from the center controller. b. Departure Procedure: Headings to fly and altitude restrictions may be issued to separate a departure from other air traffic in the terminal area. Where the volume of traffic warrants, DPs have been developed. c. Route of Flight: 1. Clearances are normally issued for the altitude or flight level and route filed by the pilot. However, due to traffic conditions, it is frequently necessary for ATC to specify an altitude or flight level or route different from that requested by the pilot. In addition, flow patterns have been established in certain congested areas or between congested areas whereby traffic capacity is increased by routing all traffic on preferred routes. Information on these flow patterns is available in offices where preflight briefing is furnished or where flight plans are accepted. 2. When required, air traffic clearances include data to assist pilots in identifying radio reporting points. It is the responsibility of pilots to notify ATC immediately if their radio equipment cannot receive the type of signals they must utilize to comply with their clearance. d. Altitude Data: 1. The altitude or flight level instructions in an ATC clearance normally require that a pilot “MAINTAIN” the altitude or flight level at which the flight will operate when in controlled airspace. Altitude or flight level changes while en route should be requested prior to the time the change is desired. 2. When possible, if the altitude assigned is different from the altitude requested by the pilot, ATC will inform the pilot when to expect climb or descent clearance or to request altitude change from another facility. If this has not been received prior to crossing the boundary of the ATC facility's area and assignment at a different altitude is still desired, the pilot should reinitiate the request with the next facility. 3. The term “cruise” may be used instead of “MAINTAIN” to assign a block of airspace to a pilot from the minimum IFR altitude up to and including the altitude specified in the cruise clearance. The pilot may level off at any intermediate altitude within this block of airspace. Climb/descent within the block is to be made at the discretion of the pilot. However, once the pilot starts descent and verbally reports leaving an altitude in the block, the pilot may not return to that altitude without additional ATC clearance. e. Holding Instructions: 1. Whenever an aircraft has been cleared to a fix other than the destination airport and delay is expected, it is the responsibility of the ATC controller to issue complete holding



instructions (unless the pattern is charted), an EFC time, and a best estimate of any additional en route/terminal delay. 2. If the holding pattern is charted and the controller doesn't issue complete holding instructions, the pilot is expected to hold as depicted on the appropriate chart. When the pattern is charted, the controller may omit all holding instructions except the charted holding direction and the statements AS PUBLISHED, e.g., “HOLD EAST AS PUBLISHED.” Controllers must always issue complete holding instructions when pilots request them. 3. If no holding pattern is charted and holding instructions have not been issued, the pilot should ask ATC for holding instructions prior to reaching the fix. This procedure will eliminate the possibility of an aircraft entering a holding pattern other than that desired by ATC. If unable to obtain holding instructions prior to reaching the fix (due to frequency congestion, stuck microphone, etc.), hold in a standard pattern on the course on which you approached the fix and request further clearance as soon as possible. In this event, the altitude/flight level of the aircraft at the clearance limit will be protected so that separation will be provided as required. 4. When an aircraft is 3 minutes or less from a clearance limit and a clearance beyond the fix has not been received, the pilot is expected to start a speed reduction so that the aircraft will cross the fix, initially, at or below the maximum holding airspeed. 5. When no delay is expected, the controller should issue a clearance beyond the fix as soon as possible and, whenever possible, at least 5 minutes before the aircraft reaches the clearance limit. 6. Pilots should report to ATC the time and altitude/flight level at which the aircraft reaches the clearance limit and report leaving the clearance limit. (ii) Mention the approximate obstruction clearances requirements of the current airports. (8)

Ans: Air traffic is responsible for obstacle clearance when issuing a “descend via” instruction to the pilot. The descend via is used in conjunction with STARs/RNAV STARs/FMSPs to reduce phraseology by not requiring the controller to restate the altitude at the next waypoint/fix to which the pilot has been cleared. The ILS glide slope is intended to be intercepted at the published glide slope intercept altitude. This point marks the PFAF and is depicted by the ”lightning bolt” symbol on U.S. Government charts. Intercepting the glide slope at this altitude marks the beginning of the final approach segment and ensures required obstacle clearance during descent from the glide slope intercept altitude to the lowest published decision altitude for the approach. Terminal Arrival Area (TAA): The TAA provides the pilot and air traffic controller with a very efficient method for routing traffic into the terminal environment with little required air traffic control interface, and with minimum altitudes depicted that provide standard obstacle clearance compatible with the instrument procedure associated with it. Minimum MSL altitudes are charted within each of these defined areas/subdivisions that provide at least 1,000 feet of obstacle clearance, or more as necessary in mountainous areas. Where lower minimum vectoring altitude (MVAs) are required in designated mountainous areas to achieve compatibility with terminal routes or to permit vectoring to an IAP, 1,000 feet of obstacle clearance may be authorized with the use of Airport Surveillance Radar (ASR). The minimum vectoring altitude will provide at least 300 feet above the floor of controlled airspace. Visual Segment of a Published Instrument Approach Procedure: Instrument procedures designers perform a visual area obstruction evaluation off the approach end of each runway authorized for instrument landing, straight-in, or circling. Since missed approach obstacle clearance is assured only if the missed approach is commenced at the published MAP or above the DA/MDA, the pilot should have preplanned climb out options based on aircraft



performance and terrain features. Obstacle clearance is the sole responsibility of the pilot when the approach is continued beyond the MAP. Vertical Descent Angle (VDA) on Non-precision Approaches: The pilot must determine how to best maneuver the aircraft within the circling obstacle clearance area in order to land. Pilot Operational Considerations When Flying Non-precision Approaches: Pilots must be especially vigilant when descending below the MDA at locations without VDPs. This does not necessarily prevent flying the normal angle; it only means that obstacle clearance in the visual segment could be less and greater care should be exercised in looking for obstacles in the visual segment. ILS or RNAV (GPS) charts: Some RNAV (GPS) charts will also contain an ILS line of minima to make use of the ILS precision final in conjunction with the RNAV GPS capabilities for the portions of the procedure prior to the final approach segment and for the missed approach. Obstacle clearance for the portions of the procedure other than the final approach segment is still based on GPS criteria. Obstacle clearance is provided to allow a momentary descent below Decision Altitude (DA) while transitioning from the final approach to the missed approach. The aircraft is expected to follow the missed instructions while continuing along the published final approach course to at least the published runway threshold waypoint or MAP (if not at the threshold) before executing any turns. Descent to the procedure turn (PT) completion altitude from the PT fix altitude (when one has been published or assigned by ATC) must not begin until crossing over the PT fix or abeam and proceeding outbound. Some procedures contain a note in the chart profile view that says “Maintain (altitude) or above until established outbound for procedure turn”. Newer procedures will simply depict an “at or above” altitude at the PT fix without a chart note. Both are there to ensure required obstacle clearance is provided in the procedure turn entry zone. Obstacle Clearance: Final approach obstacle clearance is provided from the start of the final segment to the runway or missed approach point, whichever occurs last. Side-step obstacle protection is provided by increasing the width of the final approach obstacle clearance area.

Circling approach protected areas are defined by the tangential connection of arcs drawn from each runway end. The arc radii distance differs by aircraft approach category (see FIG 5-4-26). Because of obstacles near the airport, a portion of the circling area may be restricted by a procedural note: e.g., “Circling NA E of RWY 17-35.” Obstacle clearance is provided at the



published minimums (MDA) for the pilot who makes a straight-in approach, side-steps, or circles. Once below the MDA the pilot must see and avoid obstacles. Executing the missed approach after starting to maneuver usually places the aircraft beyond the MAP. The aircraft is clear of obstacles when at or above the MDA while inside the circling area, but simply joining the missed approach ground track from the circling maneuver may not provide vertical obstacle clearance once the aircraft exits the circling area. Additional climb inside the circling area may be required before joining the missed approach track. Missed Approach, for additional considerations when starting a missed approach at other than the MAP. Precision Obstacle Free Zone (POFZ): A volume of airspace above an area beginning at the runway threshold, at the threshold elevation, and centered on the extended runway centerline. The POFZ is 200 feet (60m) long and 800 feet (240m) wide. The POFZ must be clear when an aircraft on a vertically guided final approach is within 2 nautical miles of the runway threshold and the reported ceiling is below 250 feet or visibility less than 3/4 statute mile (SM) (or runway visual range below 4,000 feet). If the POFZ is not clear, the MINIMUM authorized height above touchdown (HAT) and visibility is 250 feet and 3/4 SM. The POFZ is considered clear even if the wing of the aircraft holding on a taxiway waiting for runway clearance penetrates the POFZ; however, neither the fuselage nor the tail may infringe on the POFZ. The POFZ is applicable at all runway ends including displaced thresholds. Circling Minimums: In some busy terminal areas, ATC may not allow circling and circling minimums will not be published. Published circling minimums provide obstacle clearance when pilots remain within the appropriate area of protection. Pilots should remain at or above the circling altitude until the aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers. Circling may require maneuvers at low altitude, at low airspeed, and in marginal weather conditions. Pilots must use sound judgment, have an in-depth knowledge of their capabilities, and fully understand the aircraft performance to determine the exact circling maneuver since weather, unique airport design, and the aircraft position, altitude, and airspeed must all be considered. The published missed approach procedure provides obstacle clearance only when the missed approach is conducted on the missed approach segment from or above the missed approach point, and assumes a climb rate of 200 feet/NM or higher, as published.

7. (i) Explain the four elements of the RADAR control and non RADAR control with the help of a neat sketch. (8)

Ans: Refer Question No. 20 in Part B Ques and Ans.

(ii) An option is given either to improve an existing airport on to develop a new airport. What will be the governing considerations? (8)

Ans: Increase of airport and airspace capacity

Increase of airport and airspace capacity ACI POLICY

ACI RECOMMENDED PRACTICE / COMMENT

1. ACI believes that technical and operational means should be developed to improve airport and airspace capacity at existing facilities, as well as the building of new capacity ACI supports closer cooperation with ANSPs to develop better

1. The capacity of a given airport and runway system is determined by many factors, such as airfield layout, the air traffic control system and its management, the type and mix of aircraft, traffic peaking, weather conditions, environmental considerations, etc. Some of these factors can be accurately assessed, while others are site specific, very difficult to quantify and subject to rapid change.



models, tools and procedures to determine capacity ACI considers that a useful measure of the performance of airports or airspace management can be derived from a careful assessment of delay information.

In order to make realistic judgments and comparisons with regard to capacity, there would have to be universal agreement on the specific details of each factor and, since there are so many variables, it is doubtful whether any uniform operational measurement of potential capacity could be developed. Measurement and analysis of runway occupancy and pilot performance may also be appropriate. Runway occupancy should be defined as in 5.11.4 below. Improvements in system capacity cannot be achieved by any one sector acting in isolation. The air transport industry must work in close cooperation with governments, regulatory agencies and air navigation service providers to achieve the full capacity potential of existing facilities and to enhance them, where possible, through the adoption of new technologies and enhancements to procedures which permit higher movement rates in a safe operational manner. In addition, major initiatives will be necessary to develop new facilities required for airports to meet growing demand. New technologies and practices which provide the means of increasing capacity should be assessed and implemented whenever there is proven economic benefit.

2. ACI supports the further development and the introduction of ICAO’s CNS/ATM (Communications, Navigation and Surveillance/Air Traffic Management) systems concept, as well as the continued use of the Instrument Landing System where essential, until its replacement by new precision approach and landing systems.

2. ACI strongly supports accelerated deployment of the Global Navigation Satellite System (GNSS), including related Augmentation Systems and procedures to support precision approach and landing capability, and thereby optimize system capacity. ACI supports equipage of aircraft with Multi-Mode Receivers (MMR) to enable aircraft so equipped to operate flexibly during the transition period from existing precision approach and landing systems to new systems, regardless of the system deployed at a particular airport to support all-weather operations. ACI supports the development of standard criteria for certificating procedures using GNSS, as already developed for RNP/ RNAV. These may enable more flexibility in SIDS and STARS, including curved approaches, which may assist in noise mitigation

3. ACI supports further research programmes and activities aimed at mitigating the effect of wake vortices, in order to reduce aircraft separations while maintaining safety. 4. To minimize runway occupancy times by aircraft, the runway and taxiway infrastructure should be optimized, including studies of

4. ACI encourages the appropriate location along runways of rapid exit and access taxiways whose design complies with ICAO specifications and whose layout does not increase the risk of runway incursions.



To improve airport and airspace capacity, simultaneous operations on parallel or near-parallel instrument runways should be considered as a means of optimizing the use of new or existing parallel runways. ACI POLICY 5. ACI supports all efforts to achieve simultaneous operations on parallel or near-parallel instrument runways under visual and instrument meteorological conditions which are consistent with operational safety and efficiency.

5. ACI encourages the ICAO work programme to evaluate the use of GNSS for the purpose of supporting simultaneous operations on close-spaced parallel instrument runways.

6. At airports with intersecting runways, to enhance capacity Simultaneous Intersecting Runway Operations (SIRO) may be allowed following appropriate hazard analysis and risk assessment

6. SIRO should be performed only when the necessary safety measures are effective, for instance as proposed in the ICAO European Air Navigation Plan (EANP). SIRO may include both take-offs (intersection take-offs, multiple line-ups) and landings (Land and Hold Short – LAHSO)

8. Write in detail on air transportation in India with special references to the civil aviation

department Ans: “Aerodrome Reference Code or Special References to Civil Aviation” means a code used for planning purposes to classify an aerodrome with respect to the critical aircraft characteristics for which the aerodrome is intended; AERODROME FACILITY REFERENCE CODE: 1 – The aerodrome facility reference code, also to be known as the aerodrome reference code, is a two-element, alpha-numeric notation (for example 1B, 3C) derived from the critical aeroplane for that aerodrome facility. The code number is based on the aeroplane reference field length and the code letter is based on the aeroplane wing span and the outer main gear wheel span. As detailed below, a single element may sometimes suffice. 2 – The aerodrome reference code provides a method of grouping aeroplanes with different characteristics (eg. wing span, outer main gear wheel span, approach speed and all-up mass) which behave similarly when landing, taking-off or taxying. This, in turn, enables standards for aerodrome facilities such as runways to be set in terms of a small number of aeroplane groups, rather than individually for a large number of separate aeroplanes. The task of the standard setting authority and of the aerodrome operator is thus simplified. 3 – As the aerodrome reference code notation is derived from aeroplane and not aerodrome characteristics, it applies to the individual aerodrome facilities (eg, runways and taxiways) and indicate their suitability for use by specific groups of aeroplanes. Thus at the same aerodrome there may exist, for example, a code 4E runway, a code 1A runway, a code C taxiway and a code 2 runway strip ( a single element sufficing in the latter case). 4 – In many cases to determine the appropriate design standard for an aerodrome facility, it is necessary first to identify the aeroplanes for which the facility is intended, and then to determine the aerodrome reference code notation for the most critical of these aeroplanes. The particular

elements such as the optimal location of rapid exit and access taxiways and their lighting and marking.

Runway occupancy time is an increasingly important factor in determining airport capacity. Another important factor in minimizing runway occupancy time is the maintenance of adequate runway surface friction characteristics



standard for the facility is then related to the more demanding of the two criteria (the number or the letter) or to an appropriate combination of both. 5 – The code number for the critical aeroplane is to be determined from Table 7–1 by entering the aeroplane reference field length and reading off the corresponding code number.

6 – The code letter for an aeroplane is to be obtained from Table 7–2 by deriving the code letter applicable to the wing span, and separately deriving the code letter applicable to the outer main gear wheel span. The code letter to be used is the more senior of these letters where A is the junior.

7 – The general dimensions, of a typical aeroplane, are shown in the diagrams below.

8 – A list of representative aeroplanes operating in Australia and others, chosen to provide an example of each possible aerodrome reference code number and letter combination, is shown in the



table below (sample only). For a particular aeroplane the table also provides data on the aeroplane reference field length (ARFL), wing span and outer main gear wheel span used in determining the aerodrome reference code. For aerodrome planning purposes, data is also provided on the overall aeroplane length, maximum take-off weight and tyre pressure of main wheel tyres. It should be noted that the data provided is indicative only, for instance, factors such as engine type or flap settings can result in a different aeroplane reference field length. Exact values of a particular aeroplane’s performance characteristics should be obtained from information published by the aeroplane manufacturer

9. Write short notes on :

(i) Airway aids and terminal aids (8) Ans: Airway aids: In the early days of flight, there were no navigation aids to help pilots find their way. Pilots flew by looking out of their cockpit window for visual landmarks or by using automobile road maps. These visual landmarks or maps were fine for daytime, but airmail operated around the clock. In 1919 - bonfires and the first artificial beacons to help with night navigation. By July 1923, Bruner's ideas for lighted airport boundaries, spot-lit windsocks, and rotating beacons on towers had taken hold. Beginning in 1923, the Post Office worked to complete a transcontinental airway of beacons on towers spaced 15 to 25 miles (24 to 40 kilometers) apart, each with enough brightness, or candlepower, to be seen for 40 miles (64 kilometers) in clear weather. Each tower had site numbers painted on it for daytime identification. At night, the beacons flashed in a certain sequence so that pilots could match their location to the printed guide that they carried. Besides the rotating beacon, one fixed tower light pointed to the next field and one to the previous tower, forming an aerial roadway. Official and emergency fields were lit with green lights while dangerous fields were marked with red. Established minimum lighting requirements for all airmail stations: a 500-watt revolving searchlight, projecting a beam parallel to the ground to guide pilots; another searchlight projecting into the wind to show the proper approach; The use of lighted airways allowed pilots to fly at night, but pilots still needed to maintain visual contact with the ground. A really useful air system demanded two-way voice communication and the ability to find out about changing weather conditions while in flight. Pilots could only receive weather information and details about other planes in the air just before takeoff. If



conditions changed while flying, the ground had no way to warn them. A pilot, too, had no way of communicating with the ground. The Aeronautics Branch stepped up installation of four-course radio ranges, and this technology became standard for civil air navigation through World War II. Pilot to use only aircraft instrument guidance to take off, fly a set course, and land. He used the four-course radio range and radio marker beacons to indicate his distance from the runway. An altimeter displayed his altitude, and a directional gyroscope with artificial horizon helped him control his aircraft's orientation, called attitude, without seeing the ground. These technologies became the basis for many future developments in navigation. First ultrahigh-frequency radio range system for scheduled airline navigation, eventually expanding use of such equipment. Advances in radio very high frequency (VHF) omni-directional radio range (VOR) that allowed pilots to navigate by watching a dial on their instrument panel rather than by listening to the radio signal. The FAA began using distance-measuring equipment on its entire system. This equipment allowed aircraft to determine their distance from known checkpoints in order to confirm their position. The first Doppler radar version of the VOR system made it more accurate for longer distances. The FAA participated with the National Aeronautics and Space Administration in the first public demonstration of a new system in March 1967 that would use orbiting satellites to transmit navigation data from aircraft to ground stations. The test was followed by further development of aircraft antennas to send and receive satellite messages. In October 1969, 16 area navigation routes were developed. Previously, pilots had flown directly toward or away from the ground-based radio navigation aid (a VOR or VORTAC). This aid transmitted a course along invisible lines called radials. With area navigation, pilots could fly any pre-selected flight path roughly within the boundaries of that local system while an onboard computer tracked and reported the aircraft's position. Courses could be established along the shortest path within these route segments. Navigation aids, the computers supporting the system, and cockpit displays and instruments to send and receive navigation data all improved steadily. Additional navigation technologies are in partial use or development, including the Global Positioning System both to locate and help control aircraft by satellite, the Future Air Navigation System for remote and oceanic flights, and the Communication, Navigation and Surveillance for Air Traffic Management system. These technologies combine the need for point-to-point navigation and for higher quality voice and data communication with the need for air traffic control--the safe separation of aircraft from hazards and other aircraft. Terminal aids: an airfield equipped with control tower and hangars as well as accommodations for passengers and cargo. An airport (terminal) is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport. An airport consists of at least one surface such as a runway for a plane to take off and land, a helipad, or water for takeoffs and landings, and often includes buildings such as control towers, hangars and terminal buildings. Area Control Centres (ACCs): Area Control Centres provide air traffic control, information services and alerting services for aircraft within a designated area. ACCs normally divide their assigned airspace into sectors that are controlled by a controller or team of controllers. Control services are provided through a combination of radar, information technology, voice communication and highly skilled personel applying strict and proven separation criteria and procedures; to ensure safe, consistent separation and orderly, efficient flow of traffic from origin to destination. NAV CANADA operates 7 Area Control Centres in Gander, Moncton, Montreal, Toronto, Winnipeg, Edmonton, and Vancouver.



Air Traffic Control Towers (ATCs) : Air Traffic Controllers working in Control Towers provide pilots approaching and departing busy airports with clearances and instructions to ensure their aircraft have sufficient separation (horizontal, lateral, and vertical distance from each other). Tower controllers also provide flight information to aircraft operating within designated airspace around their airports. At busier airports monitoring of ground movements is enhanced through ground surveillance radar systems. NAV CANADA operates 41 control towers across the country. Flight Service Stations (FSSs): Flight Service Stations (FSS) provide resources for flight planning, access to briefings on weather and other preflight information, aeronautical information, enroute and airport advisory services, vehicle control services, monitoring of navaids, VHF/DF assistance and alerting of Search and Rescue centres for overdue aircraft. NAV CANADA has 58 Flight Service Stations. Flight Information Centres (FICs): FICs centralize the provision of those flight information services that are not location dependent, providing pilots with efficient, seamless flight planning, enroute services and better access to flight information services. They are a one-stop shop for flight planning and in-depth interpretive weather briefings provided by qualified specialists, using the latest computer and communications technology. Services are offered pre-flight and en route. Aerodrome Radio Stations (ARS): Aerodrome Radio Stations provide aviation weather and communications services at designated sites. These facilities are equipped with meteorological instruments for monitoring and recording aviation surface weather, and communications equipment for providing operational information to pilots. They are operated by observers/communicators who are usually recruited locally. Remote Communications Outlets (RCOs) and Remote Aerodrome Advisory Services (RAAS): Remote Communications Outlets are remote transmitters/receivers set up to extend the communications capabilities of FSS stations. They allow Flight Service Specialists to provide some flight information services to remote areas and aerodromes without a staffed NAV CANADA facility. When an RCO is used to provide airport advisory services at a remote aerodrome, the service is referred to as a Remote Aerodrome Advisory Service (RAAS). Landing and Navigational Aids: Landing Aids and Related Facilities directly support aircraft and assist during departure, en-route, and arrival. The Instrument Landing System (ILS) is the primary international precision approach system approved by ICAO. It provides navigational guidance signals and information on a cockpit display which guides pilots to the point of landing in reduced visibility. Radio Navigation Facilities: Radio Navigation Facilities are installed on defined flight tracks for use in the enroute phase of flight, or at aerodromes where they can be used to perform non-precision approaches under IFR conditions. Normally two or more types of Navigational Aids (NAVAIDS) are co-located at a site to provide a combination of functions and to ensure reliability. Non-directional radio beacons (NDB) transmit on a low frequency a non-directional radiation pattern. Distance Measuring Equipment (DME) responds to aircraft queries to provide cockpit display of the distance to the DME facility from a suitably equipped aircraft. VHF Omni-Directional Range/Distance Measuring Equipment is a ground-based, short-distance radio aid which provides continuous azimuth information in the form of 360 usable radials TO or FROM a station. It serves as the basis for most of the civil airways structure. The Tactical Air Navigation System is used to define the azimuth lines between the aircraft and the transmitter, and also the distance from the aircraft to the transmitter. TACAN is supplied by the military and operated and maintained. RAMP Radar Site Equipment - The air navigation system uses radar surveillance for both terminal and enroute control. Airport Surface Detection Equipment (ASDE) – At six airports surface aircraft and vehicle traffic is monitored during periods of reduced visibility through the use of Airport Surface Detection Equipment (ASDE) radar.



(ii) External aids and internal aids (8) Ans: ATC requires various types of navigational surveillance and communication equipment- both in the cockpit and on the ground. The technologies involve while widely used are fairly complex and training in their use, maintenance and repair is not trivial. Aids to aerial navigation can be broadly classified into two groups: 1. those that are located on the ground (external aids) and 2. Those installed in the cockpit (internal aids). Some aids are designed primarily for flying over oceans: other aids are only applicable to fight over land masses: and finally there are aids that can be used over either land or water. Some aids are used only during en-route portion of the flight while other aids are necessary in terminal areas near airports. The principal aids for ATC are voice communications and radar. The controller monitors the separation between aircraft by means of radar and instructs the pilot by means of voice communication. The following are some of the internal and external aids for aviation or aerodrome operation. External Aids: Airport Lighting

The majority of airports have some type of lighting for night operations. The variety and type of lighting systems depends on the volume and complexity of operations at a given airport. Airport lighting is standardized so that airports use the same light colors for runways and taxiways. Airport Beacon Airport beacons help a pilot identify an airport at night. The beacons are operated from dusk till dawn. Sometimes they are turned on if the ceiling is less than 1,000 feet and/or the ground visibility is less than 3 statute miles (VFR minimums). However, there is no requirement for this, so a pilot has the responsibility of determining if the weather meets VFR requirements. The beacon has a vertical light distribution to make it most effective from 1–10° above the horizon, although it can be seen well above or below this spread. The beacon may be an omni-directional capacitor-discharge device, or it may rotate at a constant speed, which produces the visual effect of flashes at regular intervals. The combination of light colors from an airport beacon indicates the type of airport. Some of the most common beacons are:

• Flashing white and green for civilian land airports;

• Flashing white and yellow for a water airport;

• Flashing white, yellow, and green for a heliport; and • Two quick white flashes alternating with a green flash identifying a military airport. Approach Light Systems Approach light systems are primarily intended to provide a means to transition from instrument flight to visual flight for landing. The system configuration depends on whether the runway is a precision or non-precision instrument runway. Some systems include sequenced flashing lights, which appear to the pilot as a ball of light traveling toward the runway at high speed. Approach lights can also aid pilots operating under VFR at night. Visual Glide slope Indicators Visual glide slope indicators provide the pilot with glide path information that can be used for day or night approaches. By maintaining the proper glide path as provided by the system, a pilot should have adequate obstacle clearance and should touch down within a specified portion of the runway. Visual Approach Slope Indicator (VASI) VASI installations are the most common visual glide path systems in use. The VASI provides obstruction clearance within 10° of the runway extended runway centerline, and to four nautical miles (NM) from the runway threshold. The VASI consists of light units arranged in bars. There are 2-bar and 3-bar VASIs. The 2-bar VASI has near and far light bars and the 3-bar VASI has near, middle, and far light bars. Two-



bar VASI installations provide one visual glide path which is normally set at 3°. The 3-bar system provides two glide paths; the lower glidepath normally set at 3° and the upper glidepath ¼ degree above the lower glide path. The basic principle of the VASI is that of color differentiation between red and white. Each light unit projects a beam of light, a white segment in the upper part of the beam and a red segment in the lower part of the beam. The lights are arranged so the pilot sees the combination of lights to indicate below, on, or above the glide path. Other Glide path Systems A precision approach path indicator (PAPI) uses lights similar to the VASI system except they are installed in a single row, normally on the left side of the runway. A tri-color system consists of a single light unit projecting a three-color visual approach path. Below the glidepath is indicated by red, on the glidepath is indicated by green, and above the glidepath is indicated by amber. When descending below the glidepath, there is a small area of dark amber. Pilots should not mistake this area for an “above the glidepath” indication. Pulsating visual approach slope indicators normally consist of a single light unit projecting a two-color visual approach path into the final approach area of the runway upon which the indicator is installed. The on glidepath indication is a steady white light. The slightly below glidepath indication is a steady red light. If the aircraft descends further below the glidepath, the red light starts to pulsate. The above glidepath indication is a pulsating white light. The pulsating rate increases as the aircraft gets further above or below the desired glide slope Obstruction Lights Obstructions are marked or lighted to warn pilots of their presence during daytime and nighttime conditions. Obstruction lighting can be found both on and off an airport to identify obstructions. Wind Direction Indicators

It is important for a pilot to know the direction of the wind. At facilities with an operating control tower, this information is provided by ATC. Information may also be provided by FSS personnel located at a particular airport or by requesting information on a CTAF at airports that have the capacity to receive and broadcast on this frequency. Traffic Patterns

At those airports without an operating control tower, a segmented circle visual indicator system if installed is designed to provide traffic pattern information. Usually located in a position affording maximum visibility to pilots in the air and on the ground and providing a centralized location for other elements of the system, the segmented circle consists of the following components: wind direction indicators, landing direction indicators, landing strip indicators, and traffic pattern indicators. The use of one of the external aids (e.g., a kneepad) can reduce the demands of Air Traffic Control (ATC) communication on pilots’ working memory during routine flight. The use of two external aids that may vary in ease of coordination: a conventional knee pad and an electronic notepad, or e-pad. Internal Aids:

Radio Communications

Operating in and out of a towered airport, as well as in a good portion of the airspace system, requires that an aircraft have two-way radio communication capability. For this reason, a pilot should be knowledgeable of radio station license requirements and radio communications equipment and procedures ATC Radar Beacon System (ATCRBS) The ATC radar beacon system (ATCRBS) is often referred to as “secondary surveillance radar.” This system consists of three components and helps in alleviating some of the limitations associated with primary radar. The three components are an interrogator, transponder, and



radarscope. The advantages of ATCRBS are the reinforcement of radar targets, rapid target identification, and a unique display of selected codes. Transponder The transponder is the airborne portion of the secondary surveillance radar system and a system with which a pilot should be familiar. The ATCRBS cannot display the secondary information unless an aircraft is equipped with a transponder. A transponder is also required to operate in certain controlled airspace as discussed in Chapter 14, Airspace.

10. Calculate the actual length of the runway from the following data:

Airport Elevation RL 100 Airport reference temperature 28 deg C Basic length of runway 1600 m Highest part along the length RL 98.2 Lowest part along the length RL 95.2

Ans: Refer the answer in Air Transportation and Planning by virendra kumar

ae 2035-qb

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