airport engineering-d

Airport Engineering

Fall Semester

Sept 11 to Jan 12Among ten matchmakers Lecture – 3a

CE – 241only nine will lieChinese Proverb 1

Transportation Engineering‐1(NIT‐SCEE‐NUST)

Dimensional StandardsDimensional Standards

• The introduction of the world’s largest passenger aircraft, theAirbus A‐380, as well as the smallest of certified general aviation jetaircraft, continues to affect design specifications of airport airfieldand terminal areas.

• Fuselage: The length of an aircraft is defined as the distance fromthe front tip of the fuselage, or main body of the aircraft, to theback end of the tail sectionback end of the tail section.– The length of an aircraft is used to determine the length of an

aircraft’s parking area, hangers.

f i l i i t th l th f th l t i ft t– for a commercial service airport, the length of the largest aircraft toperform at least five departures per day determines the requiredamount of aircraft rescue and firefighting equipment on the airfield.


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Dimensional Standards• Wingspan: The wingspan of an aircraft is defined as the distance

Dimensional Standards

from wingtip to wingtip of the aircraft’s main wings.– The wingspan of an aircraft is used to determine the width of

aircraft parking areas and gate spacing, as well as determining thep g g p g, gwidth and separations of runways and taxiways on the airfield.

• Maximum Height: The maximum height of an aircraft is typicallydefined as the distance from the ground to the top of the aircraft’sdefined as the distance from the ground to the top of the aircraft stail section.

Only in rare cases is an aircraft’s maximum height found elsewhereth i ft f l th Ai b B l ’ i h i ht ion the aircraft, for example, the Airbus Beluga’s maximum height is

noted as the distance from the ground to the top of the forwardfuselage entry door when it is fully extended upward in the open

itiposition.


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Dimensional Standards

• Wheelbase: The wheelbase of an aircraft is defined as the distancebetween the center of the aircraft’s main landing gear and thecenter of its nose gear, or tail‐wheel, in the case of a tail‐wheelaircraft.

• Wheel Track: An aircraft’s wheel track is defined as the distancebetween the outer wheels of an aircraft’s main landing gear. Thewheelbase and wheel track of an aircraft determine its minimumwheelbase and wheel track of an aircraft determine its minimumturning radius, which in turn plays a large role in the design oftaxiway turnoffs, intersections, and other areas on an airfield whichrequire an aircraft to turnrequire an aircraft to turn.


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IMPORTANT AERONAUTICAL TERMSIMPORTANT AERONAUTICAL TERMS

Standard AtmosphereStandard Atmosphere

Pressure Altitude

Aircraft SpeedAircraft Speed

Crosswind & Heading

Track & Crab angleTrack & Crab angle


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STANDARD ATMOSPHERESTANDARD ATMOSPHERE

– Standard Atmosphere is: ‐p• The temperature at sea level is 59°F.• The pressure at sea level is 29.92126 in Hg.• The temperature gradient from sea level to the altitude at which the temperature becomes ‐ 69.7°F is 0.003566°F/ft and 0 above.

• A relationship exists between pressures and temperature.

• When reference is made to the temperature being• When reference is made to the temperature being "above standard," it means that the temperature is higher than the standard temperature.


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PRESSURE ALTITUDEPRESSURE ALTITUDE

• Aircraft Takeoff Performance Data is related to the pressure altitude because it is dependent on the density of the air. Pressure altitude is the altitude corresponding to the pressure of thealtitude corresponding to the pressure of the standard atmosphere.

• When the atmospheric pressure drops, the air becomes thin, …………...

• For airport planning purposes, it is satisfactory to assume that the geographic and pressureassume that the geographic and pressure altitudes are equal unless the barometric pressures at a particular site are unusually low


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AIRCRAFT SPEEDAIRCRAFT SPEED

• A nautical mile is 6080 ft = 1 minute of arc of the earth's circumference.

• 1 knot is 1 nmi/h; a nautical mile is approximately 1.15 statute miles.statute miles.

• The ground speed is the speed of the aircraft relative to the ground. T i d i th d f i ft l ti t th• True airspeed is the speed of an aircraft relative to the medium in which it is travelling. (Calibrated airspeed corrected for temperature and pressure variations.)

• Reference is made to two airspeeds namely True Air• Reference is made to two airspeeds, namely, True Air Speed (TAS) and Indicated Air Speed (IAS).

• Indicated Air Speed (IAS): Uncorrected reading from the airspeed indicator


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AIRCRAFT SPEEDAIRCRAFT SPEED

• The pilot obtains the speed from an airspeed indicator, which works by comparing the dynamic air pressure due to the forward motion of the aircraft with the static atmospheric pressure having specific density.p p g p y

• At high altitudes the density becomes smaller, and thus the IAS is less than the TAS. As a very rough guide, one can add 2 % to the IAS for each 1000’ above sea levelcan add 2 % to the IAS for each 1000 above sea level to obtain TAS.

• With the introduction of jet transports the reference datum for speed is often the speed of sound Thedatum for speed is often the speed of sound. The speed of sound is defined as mach. Speed of an aircraft is quoted as in terms of TASS lli S d (V ll) i i d f f fli h• Stalling Speed (Vstall) ‐minimum speed for safe flight


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Importance of the relativeImportance of the relative velocity : •explains why airplanes take off and land on different runways on diff t ddifferent days. •Airplanes always try to take off and land into the wind.


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CROSSWIND & HEADING.

As an aircraft approaches a runway, its Heading (direction in which the nose is pointing) is dependent on the strength of the component of wind blowing across the path of the aircraft (crosswind)wind blowing across the path of the aircraft (crosswind).


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TRACK & CRAB ANGLETRACK & CRAB ANGLE

In order not to be blown laterally off the track by the wind, the aircraft must fly at an angle x from the track known as crab angle


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Crab Angle = Sin‐1 (Vc/Vh)

Problem‐2

• An aircraft is approaching runway at an a c a t s app oac g u ay at aindicated air speed of 140 knots. Cross wind component is 15 knots and wind is having a p gmagnitude of 25 knots.– Determine crab angle.Determine crab angle.

– What is ground speed of the aircraft?

– Determine Wind blown AngleDetermine Wind blown Angle

– Determine Track Speed.


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COMPONENTS OF AIRCRAFT GROSS WEIGHTCOMPONENTS OF AIRCRAFT GROSS WEIGHT

• Maximum Takeoff Weight (MTOW)Maximum Takeoff Weight (MTOW)

• Operating Empty Weight (OEW)

i i i i h ( )• Maximum Design Taxi Weight (MDTW)

• Maximum Structural Takeoff Weight (MSTOW)

• Maximum Structural Landing Weight (MSLW)g g ( )

• Maximum Design Zero Fuel Weight (MDZFW)


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Maximum Takeoff Weight (MTOW)• The Maximum Takeoff Weight or• The Maximum Takeoff Weight or

Maximum Takeoff Mass of anaircraft is the heaviest weight atwhich the aircraft has been shownto meet all the requirementsinclude many related to strengthy gof the structure, andperformance.

Th M i T k ff W i ht f• The Maximum Takeoff Weight ofan aircraft is fixed. It does not varywith altitude or air temperatureor the length of the runway to beused for takeoff or landing.

• Maximum Takeoff Weight is• Maximum Takeoff Weight isusually specified in units of Kg orlbs. 16

Operating Empty Weight (OEW)Operating Empty Weight (OEW)

• Weight of structure, power plant, furnishing,Weight of structure, power plant, furnishing, systems, unusable fuel and other unusable propulsion agents, and other items of equipment that are considered part of a particular airplane configuration.

• OEW also includes certain standard items, personnel, equipment, and supplies necessary f f ll i l di bl f l dfor full operations, excluding usable fuel and payload.


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Maximum Design Taxi Weight (MDTW)Maximum Design Taxi Weight (MDTW)

• The maximum taxi weight (MTW) (also knownThe maximum taxi weight (MTW) (also known as the Maximum Ramp Weight (MRW)) is the maximum weight authorized for maneuveringmaximum weight authorized for maneuvering (taxiing or towing) an aircraft on the ground as limited by aircraft strength and airworthinesslimited by aircraft strength and airworthiness requirements.


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Maximum Structural Takeoff Weight (MSTOW)Maximum Structural Takeoff Weight (MSTOW)

• Is the maximum certificated design weightIs the maximum certificated design weight when the brakes are released for takeoff or at the start of the takeoff roll. and is the greatest weight for which compliance with the relevant structural and engineering requirements has b d d b h fbeen demonstrated by the manufacturer.

• The maximum takeoff weight (MTOW) (also k h M i B k R lknown as the Maximum Break Release Weight)


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Maximum Structural Landing Weight (MSLW)Maximum Structural Landing Weight (MSLW)

• The maximum certificated design weight at which g gthe aircraft meets the appropriate landing certification requirements. It generally depends on the landing gear strength or the landingon the landing gear strength or the landing impact loads on certain parts of the wing structure.

• The MDLW must not exceed the MDTOW.• The maximum landing weight (MLW) is typically designed for 10 feet per seconds (600 feet perdesigned for 10 feet per seconds (600 feet per minute) sink rate at touch down with no structural damage.


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Maximum Design Zero Fuel Weight (MDZFW) orMaximum Design Zero Fuel Weight (MDZFW) or Maximum Zero Fuel Weight (MZFW)

• The maximum certificated design weight of the aircraft less all usable fuel and otherthe aircraft less all usable fuel and other specified usable agents (engine injection fluid, and other consumable propulsion agents) It isand other consumable propulsion agents). It is the maximum weight permitted before usable fuel and other specified usable fluids arefuel and other specified usable fluids are loaded in specified sections of the airplane.


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Operational DefinitionsOperational Definitions

• DTW = desired takeoff weight (or mass) is the weight of the aircraft considering fuel (includes reserve), payload and OEW to complete a given stage length (trip distance)

DTW = PL + OEW + FWDTW = PL + OEW + FW

where:PL is the payload carried (passengers and cargo)p y (p g g )OEW is the operating empty weightFW is the fuel weight to be carried (usually includes reserve fuel)


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Payload & RangePayload & Range

• Distance to which aircraft can fly withoutDistance to which aircraft can fly without refueling is referred as range. Main factor influencing range is pay load; revenueinfluencing range is pay load; revenue producing load. Other factors are route, altitude speed wind reserve fuelaltitude, speed, wind, reserve fuel.

• Maximum Payload is maximum design zero fuel weight minus operational empty weightfuel weight minus operational empty weight.


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OEWOEWOEW A‐i B‐i C‐i

MSPLPLPL

RAMP RES ROUTE RAMP RES ROUTE RAMP RES ROUTE

A ii B ii C iiOEW

OEW OEW

A‐ii B‐ii C‐ii

MSPLPL

RAMP RES ROUTE RAMP RES ROUTE RAMP RES ROUTE

Payload & RangePayload & Range


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Problem‐3The characteristics of a new aircraft recently introducedThe characteristics of a new aircraft recently introduced in domestic route service are tabulated below. The applicable regulations require one‐hour fuel reserve forapplicable regulations require one‐hour fuel reserve forthis aircraft. The aircraft has an average route speed of 432 mph and an average fuel burn of 18.5‐lb/ mile. Plot432 mph and an average fuel burn of 18.5 lb/ mile. Plot Payload versus range for this aircraft.

Max ramp weight 177 600Max ramp weight 177,600Max structural takeoff weight 176,600Max structural landing weight 158,400g g 158,400Zero fuel weight 146,010Fuel capacity 60,320


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Max structural payload 45,600

MSTOWMRW

ZFWMSLW


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airport engineering-d

Engineering

aircraft relativeto

ground speed

largest aircraft toperform

air speed ias

pressure variations

standard temperature

aircrafts maximum height

thestatic atmospheric