chapter 17 aircraft airworthiness inspection

AIRCRAFT

AIRWORTHINESS

INSPECTION

INTRODUCTION In order to ensure that aircraft are maintained to the highest standard of air-worthiness, they are managed and inspected under FAA-mandated and -approved inspection programs. Inspection programs must ensure the aircraft is airworthy and conforms to all applicable FAA aircraft specifications, type certificate data sheets, airworthiness directives, and other FAA approved data.

Inspection planning is organized around an aircraft's age, utilization, environmental conditions, and the type of operation. Examples include changes in temperature, frequency of landings and takeoffs, operation in areas of high industrial or environmental pollutants, and passenger or cargo operations. To assure proper maintenance, each inspection interval must be stated in terms of flight hours, calendar times, and cycles (the number of take-offs and landings the aircraft makes). As part of the aircraft's certification process, the aircraft manufacturer and the FAA agree on the frequency for inspection requirements on the aircraft as well as functional checks of each system. This forms the basis for the maintenance program when the aircraft is in service. Every system on the aircraft has its own inspection requirements. Typically, major system-inspection requirements are synchronized to minimize aircraft downtime and to eliminate a duplication of effort. However, it is common to have completely separate inspection cycles for the primary aircraft structure and its engines.

REQUIRED AIRWORTHINESS INSPECTIONS

On a base level, "inspect" means to examine by sight and touch. When performing inspections, the inspector measures and checks conditions against established guidelines. An inspector must be able to recognize defects and be aware of failure modes. Aircraft inspections include manual tasks such as initiating the inspection, accessing the aircraft, and responding to problems. In addition, cognitive tasks, such as search and decision making skills, are also used in the inspection process. An inspector should be able to identify and determine the accept-able degree of deterioration or defects permitted by the manufacturer's manuals or other approved data.

Initiating the inspection can begin by reviewing a maintenance checklist or work card, and under-standing the area or item to be inspected. Maintenance checklists for small aircraft (under 12,500 lbs. gross takeoff weight) must conform to FAR Part 43, Appendix D. Most aircraft manufac-turers provide inspection checklists regarding the specific aircraft they produce. Small aircraft manu-facturers' inspection schedules meet the minimum requirements of Appendix D and contain many details covering specific items of equipment installed on a particular aircraft. In addition, they often include references to service bulletins and ser-vice letters, which might otherwise be overlooked. As long as they meet the minimum requirements of Part 43 Appendix D, approved inspection checklists may also be customized and made more extensive to meet the needs of an individual owner/operator. Large and turbine powered aircraft are inspected under more encompassing inspection programs tai-lored to their specific type of aircraft and operating conditions.

Aircraft are subject to many required inspections. These range from the basic pre-flight inspection, a daily walk-around inspection, to extensive heavy maintenance checks, which involve significant dis-assembly and detailed inspection of the aircraft.

PRE-FLIGHT INSPECTIONS An FAA approved Minimum Equipment List (MEL) includes equipment that, if inoperative, may

either ground the aircraft or allow it to be flown with flight restrictions deferring maintenance for specific periods of time. An aircraft's MEL is spe-cific to its precise configuration and serial number. When a MEL item is discovered inoperative, it is reported by making an entry in the aircraft's main-tenance record. The inoperative equipment is either repaired or deferred according to the MEL instruc-tions prior to further flight. After repair, record an airworthiness release or aircraft maintenance entry to remove the flight restrictions. [Figure 17-1]

During a pre-flight inspection, all of the aforemen-tioned items are verified by the pilot along with per-forming a visual walk-around inspection. The walk-around entails referencing a pre-flight checklist and looking for obvious problems such as nicks and cracks on the propeller, missing hardware, properly inflated tires, and flight control damage. Although pre-flight checklists are primarily designed for the flight crew, an aircraft technician should also perform these checks before operating an aircraft. [Figure 17-2]

FAR PART 91 REQUIRED INSPECTIONS FAR Part 91 contains the General Operating and Flight Rules of aircraft and specifies the inspections required to determine the airworthiness of an air-craft. Subpart E of Part 91 deals with and describes the approved inspection programs for aircraft operations.

Small aircraft are governed by subpart E and must have a complete annual inspection every 12 calen-dar months. If the aircraft is operated for compensa-tion or hire, it must have a "100-hour" inspection of the same scope as an annual inspection performed every one hundred hours of operation. Large and turbine powered, multi-engine aircraft require more specific detailed inspections that are tailored to their particular flight operations.

ANNUAL INSPECTION The most common type of inspection required for small general aviation aircraft is the annual inspec-

Aircraft Airworthiness Inspection 17-3

ROCKWELL COMMANDER 500A REGISTRATION NO. OOXYZ SERIAL NO. 500A3848Q

21-1 REVISION 2

4/20/00

2. NUMBER INSTALLED

SYSTEM & SEQUENCE NUMBERS 3. NUMBER REQUIRED FOR DISPATCH

4. REMARKS OR EXCEPTION

21. AIR CONDITIONING 1. COMBUSTION HEATER

2. HEATER VENTILATION FAN

C

C

. (M) MAY BE INOPERATIVE PROVIDED: a. MAINTENANCE PULLS AND CAPS

JANITORIAL HEATER CIRCUIT BREAKER.

MAINTENANCE:

A certificated mechanic shall perform an inspection of the combustion heater. Remove nose section top access panel, a. Inspect the heater for general security,

damage and fuel leaks, Inspect for damage to any of the associated systems adjustment to the heater,

b, Replace access cover. c. Inspect heater fuel pump located inside

the nose wheel well area mounted against the top of the wheel well. Check for security, damage and fuel leaks to heater fuel pump,

d, Inspect fuel cycling solenoid valve and fuel safety solenoid valve located in the wheel well area against the lower bulkhead area looking aft, Check for security, damage and fuel leaks to any associated fuel lines in this area.

Enter a statement of work performed in the aircraft flight log and install placard.

. MAY BE INOPERATIVE PROVIDED: a. COMBUSTION HEAER IS NOT UTILIZED ON

THE GROUND, b. HEATER IS TURNED OFF PRIOR TO

LANDING. c. WINDSHIELD DEFOGGING IS NOT

REQUIRED ON THE GROUND. FINAL APPROVAL

FEDERAL AVIATION AMINISTRATION NM-FSDC-

MINIMUM EQUIPMENT LIST 13-12 04/20/00 REVISION 3

Figure 17-1. A Minimum Equipment List (MEL) includes items of equipment related to the aircraft's airworthiness. It does not con-tain items such as wings, flaps, and rudders, which are obviously required. MELs also list equipment that may be deferred with flight limitations.

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tion. Within every 12 calendar months, the aircraft must have a complete inspection performed to determine if the aircraft meets all the requirements for its certification. A calendar month is one that ends at midnight of the last day of the month. For example, if the inspection was completed on January 14, it will remain valid until midnight January 31, the following year. An aircraft may not be over flown beyond the annual due date unless a special flight permit is obtained authorizing the air-craft to be flown to an inspection facility.

The FAA specifies the details of both an annual and a 100-hour inspection in Appendix D of 14 CFR Part 43. Appendix D includes a list of items entitled, "Scope and detail of items (as applicable to the particular air-craft) to be included in annual and 100-hour Inspections." This list is not all-inclusive to each air-craft manufactured, but typical of the scope of inspec-tion the FAA requires. The manufacturer of the aircraft provides a detailed inspection checklist, which meets the minimum requirements of Appendix D, in the ser-vice manual for each aircraft it produces.

Figure 17-3 represents a portion of a typical manu-facturer's inspection checklist. The checklist shows the recommended time intervals of items inspected under a progressive inspection program, a complete inspection, or annual, including all 50,100 and 200-hour items in addition to any special inspection items.

Annual inspections must be performed by an A&P technician holding an Inspection Authorization (IA) or an inspector authorized by a certified repair sta-tion with an airframe rating. If the aircraft passes the inspection, the inspectors must write up the inspec-tion results in the maintenance records, and approve the aircraft for return to service. If for any reason the aircraft does not meet all of the airworthiness requirements, the inspector must provide a list of discrepancies and unairworthy items to the aircraft owner. The inspector may not delegate any inspec-tion responsibility to another A&P or repairman, nor may the inspector merely supervise the inspection.

However, as long as the discrepancy found does not require a major repair, any certified A&P technician may correct each discrepancy the inspector listed, and then approve the aircraft for return to service. The due date of the next annual inspection is then based on the date of the original inspection and not on the date the discrepancies were corrected. For example, if an aircraft's annual was completed on March 20, but a discrepancy repair was not com-pleted until April 15, the next annual is still due March 30 the following year.

If the aircraft does not pass the annual inspection, it may not be flown until the unairworthy condition is corrected. However, if the owner wants to fly the aircraft to a different repair location, a special flight permit may be obtained to ferry the aircraft to that alternate repair location.

100-HOUR INSPECTION If the aircraft is operated for compensation or hire, it must be given a complete inspection of the same scope and detail as the annual inspection every 100 hours of operation unless it is maintained under an FAA-approved, alternative inspection program such as a progressive inspection program. In the case of a 100-hour inspection, the time limitation may be exceeded by no more than 10 hours of flight opera-tion while enroute to an inspection facility. However, the excess time used to reach the inspec-tion location must be included in computing the next 100 hours of time in service. For example, if a 100-hour inspection was due at 1000 hours and the pilot over-flew the aircraft to 1008 hours to reach an inspection facility, the next 100-hour inspection is still due at 1100 hours of operation.

The difference between a 100-hour and an annual inspection is that a certified A&P technician may conduct the 100-hour inspection and approve the aircraft for return to service. The A&P technician who inspected the aircraft must make the proper entries in the aircraft's maintenance records and approve the aircraft for return to service before the 100-hour inspection is considered complete.

Like the inspector performing an annual, the A&P inspecting the aircraft may not merely supervise the inspection process. The maintenance technician performing the 100-hour inspection is responsible for approving the aircraft for return to service. In other words, the A&P signing off the aircraft must be the one who actually performed the inspection. However, the inspector may utilize other A&Ps or repairmen in the preparation for the inspection such as removing inspection panels, cowlings, and fairings. In addition, any certified A&P technician may repair and sign off any discrepancies found by the inspector as long as they are not major repairs or major alterations.

100-hour inspections may be signed off as annual inspections if an A&P mechanic holding an inspec-tion authorization (IA) completed the inspections. In a sense, the aircraft could have several annuals performed in one calendar year at each 100 hours of operation. However, a 100-hour inspection may not take the place of an annual inspection. If an aircraft is operated under the requirements of an annual

77-6 Aircraft Airworthiness Inspection

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Q m UJ UJ to 1 Aircraft Exterior • 2. Aircraft Structure © 3. Windows, windshield, doors and seals s 4. Seat stops, seat rails, upholstery, structure and mounting G 5. Seat belts and shoulder harnesses e 6. Control column bearings, sprockets, pulleys, cables, chains and turnbuckles 0 7. Control lock, control wheel and control column mechanism O 8. Instruments and markings s 9. Gyros central air filter • 13 10. Magnetic compass compensation 5 11. Instrument wiring and plumbing • 12. Instrument panel, shock mounts, ground straps, decals and labeling • 13. Defrosting, heating and ventilating systems and controls e 14. Cabin upholstery, trim sun visors and ash trays o 15. Area beneath floor, lines, hose, wires and control cables o 16. Lights, switches, circuit breakers, fuses and spare fuses e 17. Exterior lights Q 18. Pitot and static systems o 19. Stall warning unit and pitot heater • 20. Radios, radio controls, avionics and flight instruments a 21. Antennas and cables e 22. Battery, battery box and battery cables o 23. Battery electrolyte 14 24. Emergency locator transmitter G 15 25. Oxygen system 0 26. Oxygen supply, masks and hose • 16 27. Deice system plumbing 28. Deice system components • 29. Deice system boots ii

CONTROL SYSTEMS

In addition to the items listed below, always check for correct direction of movement, correct travel and correct cable tension.

1. Cables, terminals, pulleys, pulley brackets, cable guards, turnbuckles and fairleads 2. Chains, terminals, sprockets and chain guards 3. Trim control wheels, indicators, actuator and bungee 0 4. Travel stops 5. Decals and labeling a 6. Flap control switch, flap rollers and flap position indicator * 7. Flap motor, transmission, limit switches, structure, linkage, belt cranks, etc. 8. Flap actuator jackscrew threads • 9. Elevators, trim tab, hinges and push-pull tab 17 10. Elevator trim tab actuator lubrication and tab free-play inspection

11. Rudder pedal assemblies and linkage 18 12. External skins of control surfaces and tabs 13. Ailerons, hinges, and control rods © 14. Internal structure of control surfaces 15. Balance weight adjustment I

Figure 17-3. (1 Of 2)


SPECIAL INSPECTION ITEMS 1. First 25 hours, refill with straight mineral oil (MIL-L-6082) and use until a total of 50 hours

have accumulated or oil consumption has stabilized; then change to ashless dispersant oil. Change filter element each 50 hours, or every six months.

2. Clean filter, replace as required. 3. Replace hoses at engine overhaul or after 5 years, whichever comes first. 4. General inspection every 50 hours. 5. Each 1000 hours, or to coincide with engine overhaul. 6. Each 100 hours for general condition, lubrication and freedom of movement. These

controls are not repairable. Replace every 1500 hours or sooner if required. 7. Each 500 hours. 8. Internal timing and magneto-to-engine timing limits are described in the engine service

manual. 9. Remove insulation blanket or heat shields and inspect for burned area, bulges or cracks.

Remove tailpipe and ducting; inspect turbine for coking, carbonization, oil deposits and impeller for damage.

10. First 100 hours and each 500 hours thereafter. More often if operated under prevailing wet or dusty conditions.

11. If leakage is evident, refer to Governor Service Manual. 12. At first 50 hours, first 100 hours, and thereafter each 500 hours or one year, whichever

comes first 13. Replace each 500 hours. 14. Check electrolyte level and clean battery compartment each 50 hours or each 30 days. 15. Refer to manufacturer's manual. 16. Inspect masks, hose and fittings for condition, routing and support. 17. Refer to maintenance manual. 18. Lubrication of the actuator is required each 1000 hours or three years. 19. Each five years replace all rubber packings, back-ups and hydraulic hoses in both the

retraction and brake systems. Overhaul all retraction and brake system components. 20. Replace check valves in turbocharger oil lines each 1000 hours. 21. Check alternator belt tension.

Figure 17-3. (2 Of 2) An excerpt of a typical manufacturer's inspection checklist utilized during annual inspections that outlines the required inspection items. This inspection checklist is multi-functional. It outlines 50-hour, 100-hour, 200-hour, and annual inspec-tion intervals.

inspection, it must be inspected by an A&P who holds an IA rating, or certified repair station inspec-tor and be signed off as an annual inspection only.

PROGRESSIVE INSPECTION At times, aircraft operators may feel that it is not economical to keep the airplane out of commission long enough to perform a complete annual inspec-tion at one time. In which case, the owner may elect to use a progressive inspection schedule. A progres-sive inspection is exactly the same in scope and detail as the annual inspection but allows the work-load to be divided into smaller portions and per-formed in shorter time periods. For example, the engine may be inspected at one time, the airframe inspection may be conducted at another time, and components such as the landing gear at another. Progressive inspection schedules must ensure that the aircraft will be airworthy at all times and con-

form to all applicable FAA aircraft specifications, type certificate data sheets, airworthiness direc-tives, and other data such as the manufacturer's ser-vice bulletins and service letters.

The manufacturer provides guidelines to help an operator select an appropriate inspection program for their specific operation. For example, if an air-craft is flown more than 200 hours per calendar year, a progressive inspection program is most likely recommended to reduce aircraft downtime and overall maintenance costs.

Again referring to Figure 17-3, this aircraft inspection chart outlines a typical schedule used in a progressive inspection program. As shown in the chart, there are items inspected at 50,100, and 200 hours, in addition to special inspection items that require servicing or inspection at intervals other than 50, 100 or 200


hours. The inspection intervals are separated in such a way to result in a complete aircraft inspection every 200 flight hours. This particular inspection program would not be recommended or practical unless the aircraft is flown more than 200 hours per year.

Before a progressive inspection schedule may be implemented, the FAA must approve the inspection program. The owner must submit a written request outlining their intended progressive inspection guidelines to the local FAA Flight Standards District Office (FSDO) for approval. After approval, and before the progressive inspection program may begin, the aircraft must undergo a complete annual inspection. After the initial complete inspection, routine and detailed inspections must be conducted as prescribed in the progressive inspection sched-ule. Routine inspections consist of visual and oper-ational checks of the aircraft, engines, appliances, components and systems normally without disas-sembly. Detailed inspections consist of thorough checks of the aircraft, engines, appliances, compo-nents and systems including necessary disassembly. The overhaul of a component, engine, or system is considered a detailed inspection.

A progressive inspection program requires that a current and FAA-approved inspection procedure manual for the particular airplane be available to the pilot and maintenance technician. The manual explains the progressive inspection and outlines the required inspection intervals. All items in the inspection schedule must be completed within the 12 calendar months that are allowed for an annual inspection. The progressive inspection differs from the annual or 100-hour inspection in that a certified mechanic holding an inspection authorization, a certified repair station, or the aircraft manufacturer may supervise or conduct the inspection.

If the progressive inspection is discontinued, the owner or operator must immediately notify, in writ-ing, the local FAA Flight Standards District Office (FSDO) of the discontinuance. In addition, the first complete inspection is due within 12 calendar months or, in the case of commercial operations, 100 hours of operation from the last complete inspection that was performed under the progres-sive inspection schedule.

LARGE and TURBINE POWERED MULTI-ENGINE AIRCRAFT Large (over 12,500 lbs. gross takeoff weight) and multi-engine turbine aircraft operating under FAR Part 91, require inspection programs tailored to the specific aircraft and its unique operating condi-tions. These unique conditions would include sce-

narios such as high flying times, aircraft operated in extremely humid environments, or in extremely cold or wet climates. Because of the size and com-plexity of most turbine-powered aircraft, the FAA requires a more detailed and encompassing inspec-tion program to meet the needs of these aircraft and flying conditions. Although they may be operated under Part 91, large and turbine-powered aircraft are often inspected under programs normally uti-lized by air carrier or air taxi operations.

The registered owner or operator of a large or tur-bine-powered aircraft operating under Part 91 must select, identify in the aircraft maintenance records, and use one of the following inspection programs: a continuous airworthiness inspection program, an approved aircraft inspection program (AAIP), the manufacturer's current recommended inspection program, or any other inspection program developed by the owner/operator and approved by the FAA. The exception is in the case of turbine-powered rotorcraft operations, in which case, the owner/oper-ator may choose to use the inspection provisions set out for small aircraft: annual, 100-hour, or progres-sive inspection programs. After selection, the opera-tor must submit an inspection schedule, along with instructions and procedures regarding the perfor-mance of the inspections, including all tests and checks, to the local FAA FSDO for approval.

A continuous airworthiness inspection program is designed for commercial operators of large aircraft operating under FAR Part 121, 127, or 135. It is one element of an overall continuous airworthiness maintenance program (CAMP) currently utilized by an air carrier that is operating that particular make and model aircraft. [Figure 17-4]

Figure 17-4. Large turbine powered corporate jet owners may elect to use a continuous airworthiness inspection program because of the complexity of the aircraft and its systems.

A continuous airworthiness inspection program might be chosen under Part 91 operations when an air carrier purchases or leases an aircraft operating


under another air carrier's 121 certificate. For exam-ple, Airline B purchases an aircraft from Airline A. The aircraft must be operated under an inspection program during the transition from Airline A to Airline B. Instead of creating an entirely new inspection program tailored to the specific aircraft during this transition period, Airline B may choose to keep the aircraft on its current continuous air-worthiness inspection program until it is placed on the new owner's Part 121 operating certificate.

An approved aircraft inspection program (AAJP) may be chosen by on-demand operators who operate under Part 135. If the FAA determines that annual, 100 hour, or progressive inspections are not adequate to meet Part 135 operations, they may require or allow the imple-mentation of an AAIP for any make and model aircraft the operator exclusively uses. The AAIP is similar to the CAMP utilized by most Part 121 air carriers. This pro-gram encompasses maintenance and inspection into an overall continuous maintenance program. [Figure 17-5]

Figure 17-5. Turbo-prop aircraft typical of the type operated by air-taxi operators. Each aircraft operated by air-taxi oper-ators may be maintained under an AAIP designed specifi-cally to that particular aircraft by registration number.

A complete manufacturer's recommended inspec-tion program consists of the inspection program supplied by the airframe manufacturer and supple-mented by the inspection programs provided by the manufacturers of the engines, propellers, appli-ances, survival equipment, and emergency equip-ment installed on the aircraft. A manufacturer's inspection program is used more frequently when an aircraft is factory new. If an aircraft has several modifications, updated systems, or custom avionics not installed at the factory, the manufacturer's inspection program alone may not be adequate in the overall inspection of the aircraft and all of its installed equipment and components. In this case, another method of inspection must be chosen.

The owner of an aircraft may choose to develop their own inspection program. The recommended

manufacturer's inspection program is generally used as the basis of an owner developed inspection plan. However, deviation from the manufacturer's inspection program must be supported and approved by the FAA. The customized plan must include the inspection methods, techniques, prac-tices, and standards necessary for the proper com-pletion of the program. Most owner developed inspection programs include inspection and repair requirements only, and do not require continual maintenance performed to their aircraft.

CONFORMITY INSPECTIONS Aircraft are manufactured to FAA approved specifi-cations. Alterations made to the original design specifications of the aircraft require approval in the form of a sign-off from a certificated maintenance technician or, in the case of a major repair or alter-ation, approval from the FAA on form 33 7. The absence of approval for any alteration renders the aircraft unairworthy. A conformity inspection is an essential element of all aircraft inspection programs and performed to determine whether the aircraft conforms to or matches its approved specifications.

A conformity inspection is essentially a visual inspection that compares the approved aircraft specifications with the actual aircraft and associ-ated engine and components. A list is compiled out-lining the information gathered from the type cer-tificate data sheets (TCD), applicable supplemental type certificate data sheets (STC), major repair & alteration information (FAA Form 337), aircraft equipment list, airworthiness directive compliance record, etc. The list includes model numbers, part numbers, serial numbers, installation dates, over-haul times, and any other pertinent information obtained in the above reference documents. The mechanic performs a visual inspection and com-pares the aircraft with the compiled list of informa-tion making note of any deviation from the aircraft specifications. [Figure 17-6]

A conformity inspection is not specifically required by name, but it is inherently required at every inspection interval due to the nature of the inspec-tion; to determine whether the aircraft conforms to its certification specifications. However, a confor-mity inspection is specifically required when an aircraft is exported to or imported from another country with the intention of becoming registered in that respective country. Further, a conformity inspection is highly recommended when perform-ing a pre-purchase inspection for a prospective air-craft buyer.


Figure 17-6. (1 of 2) Typical conformity inspection checklist. A mechanic visually inspects the aircraft then documents the actual aircraft and equipment information on a conformity checklist. The checklist is then compared to the aircraft's specifications to determine airworthiness compliance.


ENGINE: MAKE:

MODEL: S/N:

TBO hours/years: Maintenance Doc & Rev. no. Engine TT: TSO Date of last Overhaul: STC's installed:

Applicable airworthiness directives

PROPELLER: MAKE:

MODEL: S/N:

TBO hours/years: Maintenance Doc & Rev. no. Prop TT: TSO Date of last Overhaul: STC's installed:


GOVERNOR: MAKE:

MODEL: S/N:

TBO hours/years: Maintenance Doc & Rev. no. Gov. TT: TSO Date of last Overhaul: STC's installed:


MAGNETOS: LH MAKE:

MODEL: S/N:

RHMAKE: MODEL: S/N: TBO hours/years: left right Maintenance Doc & Rev. no. Mageto TSO left right Date of last Overhaul: left right STC's installed:


Page 2 of 2

Figure 17-6. (2 Of 2)

Although the conformity inspection is an important part of the overall inspection process, it is one of the most common inspections overlooked or not

entirely carried out. For example, an IA performing an annual inspection is responsible for determinig the airworthiness of the aircraft. Many times,


inspectors fail to visually verify the equipment installed on the aircraft with the equipment list. In doing so, the IA may overlook a piece of equipment installed on the aircraft but not documented in the maintenance records, which could render the air-craft unairworthy. The verification of the presence of equipment installed in the aircraft, but not veri-fying that the installation was properly performed may also render the aircraft technically unairwor-thy. The inspector must not only verify the physical presence of items but also confirm whether the installation of the equipment was properly per-formed, especially if the installation was done with-out proper documentation.

A skilled and effective inspector meticulously veri-fies the installation of equipment list items. Not only verifying that they are physically in the air-craft, but also that they were properly installed and, in the case of a major repair or alteration, that a form 337 was created and approved by the FAA.

AIR CARRIER & AIR CHARTER OPERATIONS Aircraft operators regulated under FAR Part 121 or 135 must maintain their aircraft under comprehen-sive maintenance and inspection programs. One of the differences between Part 91 operations and Air Carrier operations is that Part 121 operators must continually maintain and inspect their aircraft.

Ongoing maintenance is not required on aircraft operated under Part 91. The operating rules of Part 91 only require an owner to correct discrepancies found during inspection intervals. Air carriers, on the other hand, must perform aircraft maintenance and inspection on a continual basis.

Air charter operations regulated under Part 135 offer another unique operating environment. Depending on the type of operation, and the size and complexity of aircraft operated, a range of inspection rules apply. Part 135 operators may choose from several different inspection programs depending on the number of seats and complexity of the aircraft.

PART 121 AIR CARRIER INSPECTIONS Air carriers operating under Part 121 must maintain their aircraft under a Continuous Airworthiness Maintenance Program (CAMP). A continuous air-worthiness inspection program is one element of an overall CAMP. The basic requirements of a CAMP include inspection, scheduled and unscheduled maintenance, overhaul and repair, structural inspection, required inspection items (RII), and a reliability program. Specific instructions, standards, and operations specifications for each element of the continuous airworthiness maintenance program must be included in the air carrier's maintenance manual for the specific aircraft for which it is applicable. A CAMP is a fleet program and encom-

MAINTENANCE CHECK SCHEDULE

CHECK SCOPE INTERVAL Service check Log book and maintenance forms review (for

example: time control items). Exterior visual checks and routine aircraft servicing such as hydraulic fluids, engine oil, & general lubrication. Operational checks.

Required no more than 48 elapsed calendar hours from the last Service Check, A-1, A-2, A-3, A-4, or C check.

Check: A-1 check A-2 check A-3 check A-4 check

Log book and maintenance forms review. Exterior visual check, routine and specific inspections, and routine aircraft servicing. Replacing time-limited items. Operational checks.

Required no more than 125 flight hours from the last equalized A and/or C check.

C Check Includes "A: check items in addition to detailed inspections of aircraft, engines, components, and appliances.

Required no more than 3600 flight hours from the last C check.

Check: D-1 check D-2 check D-3 check D-4 check

Includes "C" check items in addition to extensive dissassemby and opening up of the aircraft, and weight & balance. Flight test after operational checks.

Required to be performed at no more than 9000 flight hours or 3 calendar years, whichever occurs first from the last phase D check.

Figure 17-7. Typical air carrier maintenance "letter check" schedule outlining the scope and time intervals of required inspections for a specific type of aircraft. The maintenance schedule outline is used in conjunction with the specific work cards to maintain the airworthiness of the aircraft and all installed equipment.


passes the entire group of aircraft versus inspection programs regarding individual aircraft such as an AAIP, which is utilized under Part 135 air charter operations.

Like a progressive inspection program, the FAA must approve a continuous inspection program. This inspection program is extremely comprehen-sive, specific to the operator's aircraft, and requires complex maintenance facilities and large numbers of technical personnel. A continuous airworthi-ness inspection program is a program of FAA-approved inspection schedules which allow aircraft to he continually maintained in a condition of airworthiness without being taken out of service for long periods of time. This program keeps aircraft downtime to a minimum due to segmented maintenance or inspections intervals, thereby keeping the aircraft in service in a more efficient and convenient manner.

The continuous inspection program for a large air carrier may, as an example, consist of "letter check" inspection schedules. An example of a typical letter check inspection schedule is outlined in Figure 17-7. Letter checks are normally scheduled prior to due times or cycles. Over-flying due times or cycles of any required inspection is a direct violation of FAA regulations and may include large monetary fines. [Figure 17-7].

It is difficult to provide an overall description of a general air carrier inspection program because each air carrier's CAMP is designed specifically to its air-craft and type of operating conditions. Hence, every air carrier operating in the U.S. utilizes a different CAMP designed specifically for its individual needs and specific flight operations.

There are many different methods of inspection scheduling, inspection frequency, and terminology used throughout the airline industry. For example, one airline may refer to cursory line maintenance as a "daily" check, while another may refer to the same type of line check as a "service" check. The scope of these types of inspections is also designed explicitly for the particular aircraft. What is included in a daily check for one specific type of aircraft may not be comprehensive enough for another. Again, figure 17-7 illustrates a letter check schedule including phase inspections within the "A" and "D" checks regarding a specific type of aircraft.

In this schedule arrangement, service checks are

based on calendar hours while all other letter checks are based on flight hours. The completion of an "A" check eliminates the need for a service check due at the identical time interval. In other words, if a more detailed inspection is performed, it may zero out the less-encompassing inspection due time. A service check is due 48 calendar hours from the completion period of a "service", "A", "C", or "D" check. The next "A" check phase is due 125 flight hours from a completed "A", "C", or "D" check. This inspection schedule shows a series of "A" checks between each "C" check. There are twelve sets of "A" checks (A-l, A-2, A-3, A-4) between each complete heavy "C" check. "C" checks are due every 3600 flight hours and two comprehensive "C" checks are due between every heavy "D" check.

Each level of inspection must be clearly defined in the operator's continuous airworthiness inspection program. For example, a specific area of the aircraft may require only a visual inspection during pre-flight, "service checks", and "A" checks but may require a detailed inspection in the same area for a heavy "C" or "D" check. In most letter check maintenance schedules, the inspection and maintenance become more detailed and build upon the prior letter check performed.

Work cards act as control documents in the contin-uous inspection process. Job cards are issued for all aspects of CAMP inspections and are used to orga-nize inspection instructions and account for the specific steps involved. Depending on the scope of inspection, several work or job cards are refer-enced. Each work card outlines one specific area of the inspection. Figure 17-8 is an example of a work card used during a heavy "C" check regarding an air carrier aircraft. The work card provides an out-line of a specific area of the aircraft inspection. Recurring airworthiness directives and manufac-turer's service bulletins are usually incorporated on work cards also. The work card provides account-ability columns where the inspector or mainte-nance technician signs off each step as it is inspected or serviced. In addition, specific instruc-tions, including reference figures, may be included with each work card. The completed work card becomes part of the aircraft's maintenance record. [Figure 17-8]

FAR Part 121 outlines the specific approval for return-to-service requirements for air carrier operations.


FLY HIGH AIRLINES B737-200 C-Check

INSPECT LEFT ELEVATOR/TAB STRUCTURE AND HINGE FITTINGS CARD NUMBER 6-4008 A/C NUMBER STATION DATE

INSPECT LEFT ELEVATOR/TAB STRUCTURE AND HINGE FITTINGS M 1. INSPECT LEFT ELEVATOR UPPER AND LOWER SKIN (service bulletin AOT-53-02) M 2. INSPECT LEFT ELEVATOR INTERNAL STRUCTURE 3. INSPECT THE FOLLOWING L/H ELEVATOR TAB HINGES

1 a. Inspect L/H elevator tab hinge no. 1 1 b. Inspect L/H elevator tab hinge no. 2

4. INSPECT THE FOLLOWING L/H ELEVATOR AND HORIZONTAL STABILZER HINGE FITTINGS AND BEARINGS

1 a. Inspect L/H elevator No. 1 hinge bearing and bolt (AD 97-08-22) I b. Inspect L/H elevator No. 2 hinge bearing and bolt (AD 97-08-22)

5. INSPECT THE FOLLOWING L/H ELEVATOR AND HORIZONTAL STABILZER HINGE FITTINS, BEARINGS AND PLATE ASSEMBLIES

1 a. Inspect No. 3 hinge bearing plate assembly ! b. Inspect No. 4 hinge bearing plate assembly

INSPECT LEFT ELEVATOR/TAB STRUCTURE AND HINGE FITTINGS

APPLICABLE FIGURES: FIG.1

1. INSPECT LEFT ELEVATOR UPPER AND LOWER SKIN FOR DELAMINATION, CRACKS AND SIGNS OF BONDED SKIN SEPARATION.

2. INSPECT LEFT ELEVATOR INTERNAL STRUCTURE FOR CONDITION INCLUDING: a. Check internal spars, webs, ribs and stiffeners. b. Check condition of structure at front spar hinge attachment to elevator. c. Check tab lock mechanism for condition.

3. INSPECT THE FOLLOWING L/H ELEVATOR TAB HINGES FOR GENERAL CONDITION AND OBVIOUS DAMAGE. a. Inspect L/H elevator tab hinge No. 1. b. Inspect L/H elevator tab hinge No. 2.

4. INSPECT THE FOLLOWING L/H ELEVATOR AND HORIZONTAL STABILZER HINGE FITTINGS AND BEARINGS FOR GENERAL CONDITION AND OBVIOUS DAMAGE. (Refer to figure 1) a. Inspect L/H elevator No. 1 hinge bearing and bolt. b. Inspect L/H elevator No. 2 hinge bearing and bolt.

5. INSPECT THE FOLLOWING L/H ELEVATOR AND HORIZONTAL STABILER HINGE FITTINGS, BEARINGS AND PLATE ASSEMBLIES FOR GENERAL CONDITION AND OBVIOUS DAMAGE. a. Inspect No. 3 hinge bearing plate assembly. b. Inspect No. 4 hinge bearing plate assembly.

Figure 17-8. (1 of 2) Work/job card which references the "Left elevator/tab structure and hinge fitting" inspection required at a heavy "C" check. The work card includes the specific inspection steps along with supporting documentation helpful in the com-pletion of the inspection.


FIG1


PART 135 AIR CHARTER INSPECTIONS Part 135 on-demand air charter operators have sev-eral different options regarding the type of inspec-tion programs with which they must comply. Air charter companies that operate aircraft with less than 9 seats may choose to inspect these aircraft under FAR Part 91 and Part 43 rules, 100-hour or progressive inspection programs. In other words, they are not required to perform continual mainte-nance on their aircraft, only inspection and dis-crepancy repair. Air charter operators that operate aircraft with 10 or more seats are required to imple-ment a more-encompassing continual maintenance and inspection program. They may choose to implement a Continuous Airworthiness Maintenance Program [CAMP), an Approved Aircraft Inspection Program (AAIP), a current man-ufacturer's inspection program, or an operator developed inspection and maintenance program approved hy the FAA.

An approved aircraft inspection program (AAIP) is the inspection program most often implemented by FAR Part 135 operators. It is similar to a continuous airworthiness maintenance program used by Part 121 air carriers. However, AAIPs are not fleet inspection programs and do not require continual maintenance. They require continual inspection and are set up for the individual aircraft by registra-tion number and serial number. Air charter opera-tions may have several different AAIPs for different aircraft operated.

For example, an air charter operation that operates an aircraft with 9 or fewer seats may inspect that particular aircraft under 100-hour or progressive inspection intervals. The same operation may also operate several larger, complex aircraft and inspect them under separate AAIPs. It is possible for an air charter operator to use a different inspection pro-gram for each of its aircraft, progressive for one, AAIP for another, etc. [Figure 17-9]

Manufacturers' inspection programs are more spe-cific than the 100-hour or annual inspections but lack the ease and control provided by the approved aircraft inspection program. An AAIP allows the operator to choose their own maintenance and inspection schedules. An AAIP is not considered better than a manufacturer's program, however, an AAIP provides the FAA inspector with more control of the program's content. It requires the operator to validate its programs and revisions to the inspector which manufacturer's programs do not require. This

Figure 17-9. Air medical operators may operate several dif-ferent types of airplanes and helicopters and inspect each under separate inspection programs. AAIPs are not fleet programs; they are inspection programs designed for indi-vidual aircraft. A charter company that owns and operates five different aircraft could conceivably operate them under five different AAIPs; each specific to an individual aircraft.

is not to say that a manufacturer's program cannot be used, but it must be identified as an AAIP and approved for a particular operator as that operator's program, not the manufacturer's.

When establishing an approved aircraft inspection program (AAIP), it should include avionics, instru-ment systems, and appliances. These types of sys-tems are not always installed by the aircraft manu-facturer and may not be included in their recom-mended inspection program. The AAIP must include instructions and procedures for all installed systems.

Approved aircraft inspection programs are similar to continuous airworthiness inspection programs in that they both differ tremendously from operator to operator and aircraft to aircraft. An example of an AAIP might contain a daily service check, a 50-hour Preventative Maintenance Inspection (PMI), a series of 5 separate phase inspections conducted 150 hours apart, a 2500-hour major airframe inspection, and additional maintenance items that include stand-alone inspections. [Figure 17-10] [Figure 17-11]

SPECIAL INSPECTIONS Special inspections are scheduled inspections with prescribed intervals other than the normally estab-lished inspection intervals set out by the manufac-turer. Special inspections may be scheduled by flight hours, calendar time, or aircraft cycles. For instance, in the case of a progressive inspection schedule for a small Cessna, special inspections occur at intervals other than 50, 100, or 200 hours.


INSPECTION SCHEDULE OUTLINE

A/C time flight hrs

1 PHASE 2 3 4

Type of Inspection

200 X Nose landing gear area, nose gear, pilot's compartment, cabin section, rear fuselage & empennage, wings, main gear area, engines, landing gear retraction, operational inspection, post inspection.

400 X Nose section, nose avionics compartment, nose landing gear area, nose gear, pilot's compartment, cabin section, rear fuselage & empennage, wings, main landing gear area, engines, landing gear retraction, operational inspection, post inspection.

600 X Nose landing gear area, nose gear, pilot's compartment, cabin section, rear fuselage & empennage, wings, main gear area, engines, landing gear retraction, operational inspection, post inspection

800 X Nose section, nose avionics compartment, nose landing gear area, nose gear, pilot's compartment, cabin section, rear fuselage & empennage, wings, main landing gear area, engines, landing gear retraction, operational inspection, post inspection.

After "phase 4" inspection is completed, repeat inspection sequence. The complete program must be accomplished at least one time every 24 calender months. Any part of the inspection not completed is due immediately. Completion of phases 1-4 is considered a "complete inspection."

Figure 17-10. An example of a typical AAIP phase inspection schedule outline.

Special inspection items are usually explained in the notes section of the service manual inspection chapter.

Examples of special inspection items may include oil change information after an engine overhaul, the inspection and replacement of hoses at engine over-haul, and magnetic compass compensation every 1000 hours. Additionally, inspection and replace-ment of the rubber packings on each brake at 5-year intervals, and inspection and lubrication of the ele-vator trim tab actuator at 500-hour intervals may also constitute special inspection items. Each man-ufacturer outlines special inspection items specific to each model of aircraft.

Altimeter and static system inspections and certifi-cations are considered special inspections. Every aircraft operated under Instrument Flight Rules must have its altimeters and static systems inspected and certified for integrity and accuracy every 24 calendar months as required by FAR Part 91.411. The scope of the altimeter and static system certification is outlined in FAR Part 43, Appendix E. The altimeter is checked for operation and accu-racy up to the highest altitude it is used, usually the aircraft's service ceiling, and a record made of this

inspection and certification in the aircraft mainte-nance records.

The altimeter certification may be conducted by the manufacturer of the aircraft, or by a certificated repair station (CRS) holding an appropriate rating that authorizes this particular inspection. However, a certified airframe technician may perform the sta-tic pressure system leakage tests and integrity inspection but cannot perform the certification.

ATC transponder inspections are also considered special inspections. The radar beacon transponder that is required for aircraft operating in most areas of controlled airspace must be inspected each 24 calendar months by any of the following: a certifi-cated repair station approved for this inspection, a holder of a continuous-airworthiness maintenance program, or the manufacturer of the aircraft on which the transponder is installed. This test is required by FAR Part 91.413 and described in FAR Part 43, Appendix F.

The emergency locator transmitter (ELT) inspection is also considered a special inspection. FAR Part 91.207 requires the ELT inspection every 12 months. The inspection entails checking for proper


A. NOSE SECTION ATA ref. Mec

h Insp

1. Combustion heater a. Check the gap and condition of the heater spark plug 21-40-00 b. Check fuel plumbing, pump and regulator for leakage, damage, and security of attachment 21-40-00 c. Clean and inspect the system fuel filter at the inlet port of the fuel control valve 21-40-00

B. NOSE AVIONICS COMPARTMENT NOTE: There are no inspections required in this section during this phase

C. NOSE LANDING GEAR AREA 1. Electrical wiring and equipment- inspect all exposed wiring & equip for chafing & damage AC 43.13

D. NOSE GEAR 1. Wheel a. Inspect wheel for wear, damage, and corrosion 32-40-00 b. Inspect wheel bearings and races for wear, pitting, cracks, discoloration, rust, or damage 32-40-00

2. Tire a. Inspect for wear and deterioration 12-20-00 b. Check for correct inflation 12-20-00

3. Shimmy damper - Inspect for leaks, security, and attachment 4. Nose gear brace stop lugs - Inspect for cracks, damage or deterioration 5. Nose gear steering stop - Inspect steering stop for damage or distortion 6. Landing & taxi lights - Inspect for broken lens or bulbs 33-40-00 7. Steering linkage- Inspect nose gear steering mechanism & attaching hardware for wear 32-50-00 8. Nose landinq gear strut - Check strut for leakage and correct extension 32-20-00

Phase 1 Inspection (page 1 of 5)

Figure 17-11. An example of an AAIP phase 1 inspection job card and control document.


installation, battery corrosion, operation of the con-trols and crash sensor, and the ELT signal. Check the ELT battery's expiration date and record the expira-tion date for replacing or recharging the battery in the maintenance record. The expiration date must also be legibly marked on the outside of the ELT.

CONDITIONAL INSPECTIONS A conditional inspection is an unscheduled inspec-tion conducted as a result of a specific over-limit, or abnormal event. Examples of events requiring spe-cial inspections include:

• Hard landings

• Overstress conditions

Flight into severe turbulence

Flight into volcanic ash

Overtemp conditions

Overweight landings

Exceeding placarded speed of flaps and landing gear

Bird strike

Lightning strike

Foreign object damage (FOD)

INSPECTION GUIDELINES AND PROCEDURES

The inspection of an aircraft to determine its airwor-thiness requires a great amount of skill and judgment. For the most part, the items to he inspected are listed in an inspection checklist. However, how well an inspector evaluates an item's airworthiness is up to the judgement and skill of the individual. These factors combine to require the inspector to develop a system or procedure for effectively inspecting an aircraft.

It is imperative that inspectors set up a set of stan-dards in order to determine an item's airworthiness. These standards must be high enough to guarantee the airworthiness of the aircraft, but not so high to cause needless expense to the owner. The inspector must also withstand pressures applied by others to lower those standards by representing items as being airworthy when they are not. Once these stan-dards are compromised, it is very difficult to restore the integrity of an aircraft inspector.

INSPECTION FUNDAMENTALS Aircraft inspectors should be familiar with the vis-ible, measurable or otherwise detectable effects of wear and tear on an aircraft. An effective inspector is able to recognize and determine the cause of the wear and tear that is found during inspection, which makes the subsequent repair straightfor-ward. The five most common sources of wear and tear are weather, friction, stress overloads, heat, and vibration.

The damaging effects of weather can vary widely and range from surface corrosion, oxidation, wood rot, wood decay, fabric decay, fabric brittleness, fab-ric mildew and cracks, and interior damage and exterior paint oxidation due to ultra-violet rays. In addition, physical damage due to weather can range from lightning damage, hail dents, wind damage to control stops and control rigging, to surface damage due to sand and dirt erosion. Atmospheric moisture content is another consideration when inspecting an aircraft. The amount of water and salt the air holds may directly influence the potential corrosion found on the aircraft, especially aircraft based near large bodies of water and oceans. For further infor-

mation regarding the identification and treatment of corrosion, see chapter 12 of the ASrP Technician General Textbook.

Friction damage manifests in many different forms such as abrasions, burnishing, chafing, cuts, dents, elongation, erosion, galling, gouging, scratches, scoring, and tearing. In the context of this section, friction is the rubbing of one object against another that causes a destructive result. [Figure 17-12]

• Abrasion is caused by a rough substance between two moving surfaces.

• Burnishing is the polishing of a surface by the sliding contact with another, smoother, harder, metallic surface. Bearings have a tendency to burnish and should he checked and lubricated regularly.

• Chafing is the wear between two parts rub bing, sliding, or bumping into each other that are not normally in contact.

• Elongation is the oval-shaped wear of a bear ing surface around bolts, hinge pins, clevis pins, etc.

• Erosion is the loss of metal from the surface by the mechanical action of materials such as dirt, sand, or water. Propellers, leading edges of the wings and empennage, wheel fairing, landing gear, and cowlings are susceptible to erosion damage.

• Galling is the breakdown or buildup of the metal surface due to excessive friction between two parts in motion. Particles of the softer metal are torn loose and welded to the harder metal surface.

Overloading the aircraft may result in the failure or deformation of the structure, either slightly or prominently, but usually produces visible damage. The types of stress overloads that an inspector must


This nose strut shows signs of abrasion due to a lack of lubrication on the strut surface. The protective plating has also been rubbed away at the base exposing the metal underneath. The unprotected portion of the strut also shows signs of oxidation corrosion. Cleaning and lubricating the strut surface extends the life and appear-ance of the strut

This example illustrates chafing caused by the control cables rubbing the ducting found under the floor panels of

a Beech King Air.

Wheel bearings have a tendency to burnish with a lack of lubri-cation. The bearing race in this example shows signs of bur-nishing. Detailed inspection and lubrication of the bearing assembly will extend the life of the bearings.

Elongation is a defect that needs to be checked at attach points on the aircraft. The attachment plate of this hydraulic actuator shows signs of elongation of both bolt holes. The continuation of the elongation will eventually fatigue the metal to the point of fail-ure if not detected.

Figure 17-12. Examples of friction damage.

become familiar with are tension, compression, tor-sion, shear, and bending overloads. [Figure 17-13]

Tension overloads usually occur after hard landings, taxiing on rough fields, or flight in turbulent air. Failure is indicated by signs of the pulling away of fittings from the fuselage, failure of welded areas, wrinkling of metal skin, and deformed or cracked fittings.

Compression overloads may manifest as bulges in the metal skin, breaks in paint, and bows or bends in the long members such as wing struts. Wood compression may be detected by a slight ridge across the face of the member at right angles to the grain. Torsion or twisting overloads will turn one end of a part around its longitudinal axis

J I I -

This propeller shows signs of erosion on the leading edge due to sand, dirt, and foreign objects wearing away the surface metal


Tension or stretching damage may be exhibited by the pulling away of the skin from the structure of an aircraft. In this example, the lower wing skin of a damaged Beech Bonanza has been pulled away from the riveted seam exposing the interior wing area-

Figure 17-13. Examples of stress-overload damage.

while the other end is held fixed or turned in the opposite direction. Wheels caught in frozen ruts during landing may twist the land-ing gear and cause torsion damage. Careful inspection of the landing-gear torque links should be made after landing on rough or rut-ted fields. Severe air loads imposed upon the aircraft during flight through turbulent air may twist the control surfaces. Improper rigging of the wing and tail control surfaces may also cause torsion overloads by producing a posi-tive load on one side of the surface at all times.

Shear overloads result from forces that are applied to an object in an opposite but parallel direction. When a shear overload is applied, the part having the least resistance to the force will fail first. Because bolts, rivets, and clevis pins are used in areas subject to shear forces, they should be inspected for shear failure. Bent, torn, or deformed bolts, rivets, or clevis pins are good indications of shear damage.

Bending overloads cause rigid members to curve or bow away from a straight line. Hard landings, abnormal flight loads, and improper ground handling may cause bending damage. Wood or metal skin may show signs of wrin-kling, cracking, or distortion. On fabric cov-ered airplanes, a bent member may be detected by looseness or wrinkling of the fabric.

The primary source of heat damage affecting the air-craft is the powerplant. Inspectors must be familiar with direct and indirect heat sources that cause damage. Direct heat damage is normally caused by leaking exhaust gases, and, in the case of severe leaks, may allow flames to escape resulting in dev-astating consequences. Indirect heat damage may result from excessive engine compartment heat indicated by high oil and cylinder head tempera-tures, blistering paint on the engine cowling, and odors of burned oil or rubber during or after engine run-up.

The wing tip of this aircraft is bent in an upward direction illustrating bending stress overload. The inboard portion of the wing was held in place while a bending force was applied to the wing tip.

The firewall of this small aircraft was compressed in a hard landing. The firewall is constructed of stainless steel requiring a large amount of compression stress overload


Improperly installed or leaking engine baffles, mis-aligned cowlings, improper carburetor-heat control rigging, improper cowl-flap door rigging, and dirty air coolers may cause indirect heat damage. In addi-tion, the use of an improper grade of oil, and oil leakage, may also cause indirect heat damage to the aircraft and engine. [Figure 17-14]

Figure 17-14. The bubbling of the paint in addition to the exhaust trail exiting the engine cowling vent illustrates indirect heat damage.

Vibration causes many malfunctions and defects throughout the life of the aircraft. Vibration affects loose or improperly installed parts and accelerates wear to the point of failure in some cases.

Low frequency vibration can be felt or noticed by the pilot or mechanic. It is usually caused by a malfunctioning powerplant, propeller, worn engine-mount pads, loose aircraft structure joints, or improper rigging. Noticeable vibration causes abnormal wear between moving parts. Excessive clearances and poor installation are also factors affecting the level of vibration damage and should be considered when inspecting the aircraft.

For example, control surface and trim tab "free-play" limits may be extreme due to excessively worn hinges and actuator damage. Excessive free-play causes the control surface to vibrate or "flutter" in flight. The vibration then transfers through the airframe structure and causes fractures and fatigue to appear in locations remote from the source. [Figure 17-15]

INSPECTION GUIDELINES In addition to the aforementioned wear and tear effects, following is a brief outline of some of the most common deficiencies to look for in an aircraft

Figure 17-15. The cracks on the wing skin of this Piper Seneca were caused by the excessive play in the aileron hinge. During flight, vibration or "flutter" of the ailerons occurred which stressed the aircraft structure and caused stress cracks to manifest on the upper wing surface.

inspection. An inspector must be familiar with each of these areas in order to perform effective and high-quality inspections.

• Movable Parts: proper lubrication, security of attachment, binding, excessive wear, proper safety wiring, proper operation and adjust ment, proper installation, correct travel, cracked fittings, security of hinges, defective bearings, cleanliness, corrosion, deformation, and sealing and tension.

• Fluid lines and hoses: proper hose or rigid tubing material, proper fittings, correct fitting torque, leaks, tears, cracks, dents, kinks, chaf ing, proper bend radius, security, corrosion, deterioration, obstructions and foreign matter, and proper installation.

• Wiring: proper type and gauge, security, chaf ing, burning, defective insulation, loose or broken terminals, heat deterioration, corroded terminals, and proper installation.

• Bolts: Correct torque, elongation of bearing surfaces, deformation, shear damage, ten sion damage, proper installation, proper size and type, and corrosion.

• Filters, screens, and fluids: cleanliness, cont amination, replacement times, proper types, and proper installation.

• Powerplant Run-up: Engine temperatures and pressures, static RPM, magneto drop, engine response to changes of power, unusual engine noises, ignition switch operation, fuel shut- off/selector valves, idling speed and mixture settings, suction gauge, fuel flow indicator operation, engine mount security, mount bolt torque, spark plug security, ignition harness


security, oil leaks, exhaust leaks, muffler cracks and wear, security of all engine acces-sories, engine case cracks, oil breather obstruc-tions, firewall condition, and proper operation of mechanical controls.

Propellers: nicks, dents, cracks, cleanliness, lubrication, gouges, proper blade angles, blade tracking, proper dimensions, governor leaks and operation, and control linkages for proper tension and installation. Nicks on the leading edge of the blade are an important item to inspect for; they produce stress con-centrations that need to be removed immedi-ately upon discovery in order to prevent the blade from separating at the nick.

INSPECTION PROCEDURES The inspection of aircraft requires a great deal of organization and planning. Effective inspections must be performed in a logical and orderly sequence to ensure that no inspection item is over-looked or forgotten. The accepted method of per-forming an inspection that is used by the aircraft maintenance industry also includes the service and repair activities that are necessary to approve the aircraft for return to service.

The inspection of an aircraft is divided into five basic phases: pre-inspection, examination, service and repair, functional check, and the return to ser-vice phase.

PRE-INSPECTION PHASE The pre-inspection phase is very important and serves to organize the paperwork, records, tools, and equipment needed for the inspection. This phase usually includes: work order completion, compilation of the aircraft specifications, review of maintenance records, airworthiness directive research, manufacturer service bulletin and letter research, airworthiness alert research, producing the inspection checklist, and aircraft preparation.

The pre-inspection phase begins with the comple-tion of the work order which outlines and autho-rizes the performance of the services. The mainte-nance records, airworthiness directives, service bul-letins, and any other relevant service information are researched and, if applicable, added to the inspection checklist. The aircraft is cleaned, and the engine is usually run-up to check engine para-meters and to set a base line for the post-inspection run-up. Removal of inspection panels, engine cowl-ing, and interior, if required, are done during the pre-inspection phase. In addition, tools and equip-ment are made ready, and any known parts that are needed are ordered. [Figure 17-16]

WORK ORDER The work order is the agreement between the shop or mechanic and the owner of the aircraft concern-ing the work to be performed. It describes the work

Figure 17-16. During the pre-inspection phase, the aircraft is prepared for the inspection by removing all applicable inspection pan-els and completely uncowling the engine compartment. It is important to have access to as much of the aircraft, systems, and components as possible for a complete inspection.


requested and serves as a record of parts, supplies, and labor expended on the aircraft. While inter-viewing the owner, describe the work requested and any discrepancies that the owner wants repaired. The owner then signs the work order before work begins on the aircraft. [Figure 17-17]

Figure 17-17. Preparing the work-order with the customer is an important step in the pre-inspection phase of any inspection.

Clearly explain to the customer that additional charges may apply regarding maintenance per-formed to correct any discrepancy found during the inspection. It should be noted that the work order normally only estimates the total cost of the inspec-tion and any subsequent maintenance repair. It is impossible to determine the labor and parts expense of unknown discrepancies. Certain shops charge a flat rate for the inspection and charge separately for parts and labor regarding any maintenance done to the aircraft. Others may charge on an hourly basis along with any expenses for parts and supplies that are incidental to the inspection and maintenance.

At times, discrepancies are detected upon inspec-tion. It is wise to provide the owner the opportunity to choose to fix the discrepancies or not. If the owner chooses to repair any discrepancy that is found dur-ing the inspection, revise the work order ■with reference to the needed repairs. Have the owner sign the revision order before beginning the repairs.

MAINTENANCE RECORDS AND AIRCRAFT SPECIFICATION REVIEW The maintenance record and aircraft specifications review is a very important part of any inspection and takes place before the aircraft is physically examined. Maintenance records can reveal quite a bit about the care and maintenance of an aircraft. The maintenance history of the aircraft is carefully examined to determine repetitive maintenance problems, airworthiness directive compliance, any major repairs and alterations done to the aircraft,

and, on a base level, whether the aircraft has had maintenance performed in a consistent manner. Maintenance records are researched to determine information such as the type of oil in use, ELT bat-tery expiration and operational test date, altimeter and transponder test due dates, when the spark plugs were last changed, age of the battery, when vacuum system filters were last changed, life-lim-ited parts status, aircraft total time, major repair and alteration information, and engine time since overhaul (TSO). [Figure 17-18]

Figure 17-18. Thorough maintenance information research is key to an effective inspection. Without complete and correct aircraft information, important items may be over-looked during an inspection.

All aircraft must conform to their certification requirements. Therefore, the research and compi-lation of the aircraft specifications is essential to a proper conformity inspection. A conformity inspection entails a visual inspection of the entire aircraft, engine, propeller, avionics, and appli-ances using information gathered from the TCD, STCs, aircraft equipment list, and applicable air-worthiness directives. A thorough inspection starts with the research of the aircraft specifica-tions and maintenance information.

In addition to the records review, the inspection checklist must be obtained that is specific to the aircraft make and model. When performing annual or 100-hour inspections, the use of a checklist is required by FARs. The technician may design a checklist that is specific to the aircraft being inspected, or use a checklist provided by the man-ufacturer of the aircraft, engine, propeller, and installed components as long as it meets the mini-mum requirements outlined in 14 CFR part 43 Appendix D.


SERVICE BULLETINS AND LETTERS A thorough inspection includes the research and documentation of applicable service bulletins and service letters. During the records review, manufac-turer's service information is researched to verify any possible changes that were made to improve the service life or efficiency of the aircraft, engine, pro-pellers, or appliances. The manufacturer of the air-craft publishes service bulletins and letters to inform the owner of any design changes, malfunc-tions, or servicing requirements. They may require an inspection or repair to correct an unsatisfactory condition. The FAA does not require the compli-ance of service letters or bulletins. However, the owner should be encouraged to comply. Many times, service bulletin information is a precursor to a mandatory airworthiness directive (AD). Additionally, airworthiness directives may refer-ence service bulletin information for specific instructions regarding inspection and/or repair when complying with the AD.

Each manufacturer has a different service bulletin numbering system. Most will include the year in the service bulletin reference number but some do not. To perform a service bulletin search using micro-fiche, review the index of service bulletins that apply to the type and model of the aircraft, engine, propeller, and appliances and compile a list of applicable service bulletins. In addition, updated service bulletins that are received after the publish date of the microfiche are referenced in the "service bulletins received after cutoff" section of the master reference fiche and are usually referenced by ser-vice bulletin number. [Figure 17-19]

Figure 17-19. Inspections begin with service information research. This mechanic is researching service bulletin information using microfiche. Although microfiche is a valid and accurate way to research and compile current maintenance information, it is being replaced with com-puterized search programs that do not require extensive microfiche libraries. One CD-ROM takes the place of hun-dreds of microfiche making it easier and more efficient to update and research information.

If the maintenance facility utilizes a computerized search program, a search may be made that is spe-cific to the make and model of the aircraft, engine, propellers, and appliances. Most computerized search programs allow the technician to enter spe-cific search criteria, such as make and model, which makes this method more efficient and less time con-suming than microfiche. The program searches by the criteria entered into a search field and produces a list of applicable service bulletins. Again, most computerized service bulletin subscriptions will reference updated information that is received after the publish date in a specific section such as "New service bulletins." Furthermore, a number of com-puterized maintenance-information-services offer real time search capabilities over the Internet offer-ing daily updated service bulletin information.

Once the service bulletin list is compiled, confirm the applicability by comparing the serial number of the aircraft or equipment against the relevant serial numbers in the "effectivity" or "models affected" section of the service bulletin. A list of bulletins that apply by serial number is then compared to the ser-vice bulletins complied with and referenced in the maintenance records. Those that have not been complied with would then be due. Because the FAA does not require mandatory compliance with ser-vice bulletins, they should be discussed with the aircraft owner to determine if compliance is desired.

Compliance with service bulletin information at regular inspection intervals may save time and money in the long run. Many times, service bul-letins bring attention to malfunctions and design changes that eventually become important enough to warrant publishing of an airworthiness directive (AD). If the service bulletin is complied with during a regularly scheduled inspection, it may eliminate the need to perform the inspection and/or repair again to comply with a subsequent AD. The "com-pliance" section of the AD will clarify whether the accomplishment of the service bulletin satisfies the AD compliance.

AIRWORTHINESS DIRECTIVES Airworthiness directives (AD) are issued by the FAA to correct unsafe conditions that affect the safety of an aircraft. ADs are mandatory and require compliance. Thus, it is imperative to comply with all ADs that apply to the aircraft. At the beginning of every inspection, research and compile a listing of all airworthiness directives that are applicable to the aircraft, its engine, propeller and any installed component.


In the case of airworthiness directives, they may be researched in the same manner as service bul-letins: manually through microfiche or computer search programs. In addition, several maintenance information companies provide detailed searches that are applicable to the particular model of air-plane and its installed equipment for nominal fees, thus eliminating the need for inefficient research time.

Aircraft owners are required to maintain the current airworthiness directive (AD) status of their aircraft and all installed equipment. Included in the AD sta-tus is the method of compliance, AD number and revision date, whether the ADs are recurring or one-time only, and finally, the time and date when the next action is required. To improve the ability to track AD compliance, most aircraft records include a separate airworthiness directive compliance record, which keeps a cumulative record of the cur-rent AD status for a particular aircraft. Instead of looking through logbooks page by page, the AD compliance record makes researching AD informa-tion much easier by compiling AD compliance in one convenient location.

In addition to compiling the applicable AD infor-mation, the technician must be able to interpret the applicability and compliance sections in the body of the AD. Every AD applies to each aircraft or com-ponent as identified in the applicability statement regardless of the classification or category. The ser-ial number range or series of aircraft or component that is listed in the applicability statement deter-mines whether the AD is valid for that particular aircraft or component. When there is no serial num-ber range specified, the AD applies to all serial num-bers. [Figure 17-20]

INITIAL RUN-UP After completing the pre-inspection paperwork and maintenance records review, perform an engine run-up to provide a baseline of engine parameters to compare to the post-inspection run-up indications. A pre-inspection run-up also warms the engine and provides proper lubrication. Perform an engine run-up to determine whether the engine develops proper static rpm and manifold pressure, if applica-ble, and to check pressures and temperatures to be sure that they are within proper operating ranges. Check the magnetos, carburetor heat, and propellers for the proper operation, and test the generator or alternator for proper output.

During the run-up, check the operation of electrical flaps for symmetrical movement and smooth opera-

tion through the entire range of travel. Also, verify that the flap indicator agrees with the actual flap position. Check flight control movement and travel, making note of any roughness or malfunction. Verify that the ailerons move in the proper direction with alternating control inputs; rotating the yoke to the right moves the right aileron up and left aileron down and vice versa 'when rotating the yoke to the left.

Also, while the electrical power is available, check the radios for proper operation, listening for any noise that may be caused by the interference of the engine or any aircraft system. Check the magnetic compass reading for any deviation caused by elec-trical interference while the electrical systems are operating. Make sure the compass correction card, if required, is placarded.

Set the altimeters to the current barometric pressure and compare the altimeter indication with the actual field elevation where the aircraft is located making note of any discrepancy. In addition, 'while operating at high RPM, check the instrument pres-sure or vacuum for proper operating range indica-tions.

Check the operation of the fuel selector valve by selecting each fuel tank to verify consistent engine function when drawing fuel from individual tanks. Make note of any changes in engine RPM, and fuel flow or pressure fluctuations. Check the fuel pres-sure produced by the engine-driven pump and, after shutdown, by the electric boost pumps. After engine shutdown, listen to the gyro instruments as they run down to detect any bearing roughness.

After the engine is shutdown, uncowl the engine and look for any loose or disconnected lines, oil and fuel leaks, or any other irregularity. Finally, once the run-up is concluded, completely wash down the engine to remove all oil and dirt that might hinder a complete inspection.

EXAMINATION PHASE The primary purpose of the examination phase is to physically evaluate the airworthiness of the aircraft and its components. All of the subsequent activities of the inspection are dependent upon, and in sup-port of, the examination phase of the inspection.

The examination phase is the actual inspection of the aircraft. It starts with a conformity inspection, which compares the actual aircraft with its certifi-cation specifications. It then proceeds to looking at, feeling, checking, measuring, operating, moving, testing, and whatever else is needed to determine


99-16-06 - Failure of the wing attach fittings

The New Piper Aircraft, Inc.

Category - Airframe

Effective date - 09/24/1999 Recurring - No

Supersedes - N/A Superseded by - N/A

Amendment 39-11241; Docket No. 99-CE-01-AD

Applicability: Model PA-46-350P airplanes, serial number 4622191 through 4622200 and 4636001 through 4636175, certificated in any category.

Note 1: The affected serial numbers refer to airplanes that have been delivered since January 1995 and could have insufficientstrength wing attach fittings installed. Airplanes manufactured after serial number 4636175 have this problem corrected prior to delivery.

Note 2: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required within the next 100 hours time-in-service (TIS) after the effective date of this AD, unless already accomplished.

To prevent the potential for failure of the wing attach fittings caused by the utilization of substandard material, which could result in the wing separating from the airplane with consequent loss of control of the airplane, accomplish the following:

(a) Install reinforcement plates to the wing forward and aft attach fittings by incorporating the Wing to Fuselage Reinforcement Installation Kit, Piper part number 766-656. Accomplishment of the installation is required in accordance with the instructions to the above referenced kit, as referenced in Piper Service Bulletin No. 1027, dated November 19, 1998.

(b) Special flight permits may be issued in accordance with Sees. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(c) An alternate method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved the Manager FAA, Atlanta Aircraft Certification Office (ACO). The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Atlanta ACO.

Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtainedfrom the Atlanta ACO.

(d) The installation required by this AD shall be done in accordance with the instructions to the Wing to Fuselage Reinforcement Installation Kit, Piper part number 766-656, dated November 6, 1998, as referenced in Piper Service Bulletin No. 1027, dated November 19, 1998. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the New Piper Aircraft, Inc. Customer Services. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel or at the Office of the Federal Registry in Washington DC.

(e) This amendment becomes effective on September 24, 1999.

Figure 17-20. Example of an airworthiness directive regarding a Piper PA-46. ADs are set up in the same format: the heading show-ing the AD number, revision date and subject, the "applicability statement" that distinguishes the aircraft or component applica-bility, and the "compliance statement" that specifies the time and procedural requirements for AD compliance.

the condition of the aircraft and its components. A checklist is followed with a planned sequence or order in which items of the aircraft are inspected. Note the needed service and discrepancies that are discovered during the examination phase on a dis-crepancy list. The discrepancy list is used for fol-low-up repair either during the inspection or hy another certificated technician after the completion of the inspection. [Figure 17-21]

One of the most important considerations for an effi-cient inspection is that it must be systematic. Using the checklist, inspect one complete system before

going to the next. For example, check the complete aileron system from the control wheel to each aileron and back to the wheel. Then check the complete ele-vator system. Jumping from one part of a system or component to another leaves room for mistakes and the possibility of overlooking problem areas.

SERVICE AND REPAIR PHASE The service and repair phase of the inspection includes the necessary maintenance that is required to approve the aircraft for return to service and to preserve its airworthy condition. Servicing consists of tasks such as lubricating wheel bearings and


Figure 17-21. Examples of areas checked during typical inspection intervals.

A conformity inspection requires the thorough inspection of the aircraft's specifications.

A differential compression test is used to check cylinder condition. Perform the compression check while the engine is still hot to gain accurate compression indications. The increased clearances of the pistons, rings, and valves of a cold engine, in addition to the lack of lubrication, may result in air compression leakage and inaccurate indications.

Inspection mirrors and flashlights are essential tools used during the inspection process.


Ultra-sonic testing is a good way to inspect a window for hidden flaws, delamination and to check window thickness. The use of a coupling gel is essential for proper indi-cations.


moving parts, replacing and cleaning filters and screens, adding fluids, servicing the battery, and cleaning the aircraft.

Although discrepancy repair is not part of the inspec-tion itself, it is closely related and usually done con-currently with the inspection. The repair phase may include replacement, repair, and overhaul of the air-craft components and systems that are found to be deficient or unairworthy. Additionally, modifications to the aircraft that require a Supplement type certifi-cate (STC), are often done in conjunction with an annual or 100 hour inspection. Modifications that require an STC are considered major alterations, therefore, must be returned to service by an A&P mechanic with an Inspection Authorization.

FUNCTIONAL CHECK PHASE After the inspection is accomplished and all needed maintenance is completed, the maintenance techni-cian conducts functional or operational checks on the aircraft and systems. When performing an annual or 100-hour inspection, FAR part 43.15 requires a functional check on the aircraft engines. Therefore, perform a post-inspection engine run-up to deter-mine whether the power output (static and idle rpm), magnetos, fuel and oil pressures, and cylinder and oil temperatures meet the manufacturer's specifica-tions. The engine functional check phase also allows the technician to check for fuel leaks, oil leaks, and any other irregularity that may indicate something left open or loose during the inspection.

Additional functional checks are recommended to ensure that the installed systems or subsequent dis-crepancy repairs are airworthy according to the manufacturer's specifications.

After all maintenance is completed, a good wash of the aircraft to remove any trace of oil or grease left on it from the inspection is recommended. Include the windshield and all of the windows remembering to only use the proper cleaning flu-ids. Using the wrong type of chemical can damage or destroy the aircraft finishes and windows. Carefully clean the inside of the aircraft to remove any fingerprints or grease marks left during the inspection. Vacuum the carpet, straighten the seat belts, and make the inside of the cabin appears neat and organized.

An aircraft owner may not understand the intrica-cies of an inspection, but are sure to notice any grease spots or smudge marks left behind. They may feel that a person who is careless enough to leave a disorganized and unclean airplane may have been equally careless in the inspection.

RETURN-TO-SERVICE PHASE After the inspection is accomplished, you must complete the paperwork before the aircraft is approved for return to service. In the case of a 100-hour inspection, the work order is completed, the AD compliance record is filled out, and inspection entries are recorded in the maintenance logs.

Complete the work order to detail the inspection and all of the work and servicing that was per-formed. In most cases, the work order is very detailed and may be recognized as part of the air-craft records. Tally up all labor charges, cost of parts and supplies, and any special charges such as out-side labor and telephone calls related to the job. Complete and systematic maintenance documenta-tion not only protects the maintenance technician if a question ever arises concerning work that was or was not done, but it is assumed that good records normally accompany good work.

Before an aircraft can be legally flown, entries must be made in the maintenance records and signed off by the appropriately rated maintenance technician. The inspection entry and sign-off constitutes "approving the aircraft for return to service." FARs require a separate 100-hour inspection entry for each log if the owner maintains separate logbooks for the airframe, engine, and propellers. In the case of an annual inspection, an entry is only required in the airframe log. However, most inspectors enter an annual inspection entry in all logbooks, thus mak-ing maintenance record research more efficient and easy. Again, the inspection is not complete and the aircraft is not approved for return to service without the proper logbook sign-offs. Refer to the "Aircraft Maintenance Records" section of this chapter for a detailed explanation of entry requirements. [Figure 17-22] [Figure 17-23]

Figure 17-22. The inspection is not complete without the proper maintenance entry. Make sure the entry is legible and that it details the inspection performed according to the FAR requirements specific to the inspection entries.

Figure 17-23. (2 of 9)


Insp Des Item Propeller ■?

Spinner and spinner bulkhead

/K Blades Hub Bolts and nuts Engine compartment Check for evidence of oil and fuel teaks, then clean entire engine compartment prior to inspection. n>c

Engine oil, screen, filler cap, dipstick, drain plug and external filter element Oil cooler %c Induction air filter: clean, inspect, replace if needed. Induction air box, air valves, doors, and controls &L

Cold and hot air hoses Engine baffles "??C Cylinders, rockers box covers, and push rod housings ?>

Crankcase, oil sump, accessory section, and front crankshaft seal All lines and hoses 35

Intake and exhaust systems AD 97-12-06: Gascolator, tailpipe, and cowling area Ignition harness Spark plugs Compression check: Cy! 1: IVSQ

Cyl 4 $0180 Cyl 2: 7^/80 Cyl 5 yy /80

?c Crankcase and vacuum system breather lines Electrical wiring Vacuum pump and relief valve Vacuum relief valve filter Engine controls and linkage Engine shock mount pads, mount structure, and ground straps Cabin heater valves, doors, and controls Starter, solenoid and electrical connections Starter brushes, brush leads, and commutator Alternator, and electrical connections Alternator brushes, brush leads, and commutator or slip ring -pc Voltage regulator mounting and electrical leads Magnetos (external inspection) and electrical connections Magneto timing i

t

Injection system Firewall Engine cowling Fuel System Fuel strainer, drain valve, and control Fuel strainer screen and bowl Cessna 172R 100-hour inspection checklist

page 2 of 4

Figure 17 23

. (3 of 9)


Insp Des Item X Fuel tanks, fuel lines, sump drains, filler caps, and placards Drain fuel and check tank interior, attachment, and outlet screens Fuel vents, vent valves, & vent line drain ^L Fuel selector valve and placards Fuel valve drain plug f

- Engine primer Landing Gear !fe

L

Brake fluid, lines and hoses, linings, disc, brake assemblies, and master cylinders Main gear wheels, wheel bearings, step and spring strut, tires, and fairings Main and nose gear wheel bearing lubrication: clean, repack, & lubricate Steering arm lubrication Torque link lubrication ^ C Nose gear strut servicing Nose gear shimmy dampener servicing Nose gear wheels, wheel bearings, strut, steering system, shimmy dampener, tire, fairing,

and torque links

Tires Parking brake and toe brake operational check Airframe Aircraft exterior Aircraft structure Windows, windshield, and doors Seats, stops, seat rails, upholstery, structure, and seat mounting Safety belts and attaching brackets %c Control "U" bearings, sprockets, pulleys, cables, chains, and tumbuckles Control lock, control wheel, and control "U" mechanism Instruments and markings Gryos central air filter: plug vacuum line when removing filter Magnetic compass compensation Instrument wiring, and plumbing Instrument panel, shockmounts, ground straps, cover, and decals and labeling ■>

Defrosting, heating, and ventilating systems, and controls S Cabin upholstery, trim, sun visors, and ash-trays Area beneath floor, lines, hoses, wires, and control cables Lights, switches, circuit breakers, fuses, and spare fuses A Exterior lights Pitot and static systems Stall warning system Radios and radio controls %

Radio antennas Avionics and flight instruments Antennas and cables t ? c <-- Battery, battery box, and battery cables

Cessna 172R 100-hour inspection checklist page 3 of 4

Figure 17-23. (4 of 9)


Insp Des Item Battery electrolyte level: only use distilled water to maintain electrolyte level 4^ X Emergency locator transmitter (ELT): attachment, test, & expiration date - replace if expired Control System In addition to the items listed below, always check for correct direction of movement, correct travel, and

correct cable tension.

^7 C Cables, terminals, pulleys, pulley brackets, cable guards, turnbuckles, and fairleads Chains, terminals, sprockets, and chain guards ^< Trim control wheels, indicators, actuator, and bungee Travel stops All decals and labeling Flap control switch, flap rollers and tracks, flap position pointer and linkage, and flap electric

motor and transmission

Flap actuator jack screw threads Elevator and trim tab hinges, tips and control rods Elevator trim tab actuator lubrication and tab free-play inspection Rudder pedal assemblies and linkage Skin and structure of control surfaces and trim tabs Balance weight attachment Post inspection engine run-up Engine temperatures and pressures Static RPM yc Magneto drop Engine response to changes in power Unusual engine noises Fuel selector valve: operate engine on each tank position and OFF position long enough to ensure proper selector valve function. 1<- Idling speed and mixture; proper idle cut-off Alternator and ammeter operation Suction gage: %L Fuel flow indicator After shutdown, check for fuel and oil leaks. Clean up f,L. Reinstall all inspection panels and cowlings %L Wash exterior - Clean windows and windshield Clean and vacuum interior Straighten seat belts Final paperwork Update AD compliance list Complete work-order: regarding parts, supplies, and final labor figures 1s

Produce log book entries: airframe, engine, and propeller logs ''Produce list of discrepancies, if applicable

Cessna 172R 100-hour inspection checklist page 4 of 4

Figure 17-23. (5 of 9)

100-hour inspection - 172R

# Discrepancy Action Taken

1 Trt*p* ll t,t~ -fek&.f-"t"

^"cpltf c< prop c I ier fi, kc_eM"" Removed S/N 3Ht I-12- ~A Installed S/N ㄎ&<(-$

spec MECH INSP DATE t jtl/oo

2 *t propeller blade. % ?

Ckecfe" AActatAieti oθiaiCAT'onS. Removed S/N

Installed S/N

MECH 5T

INSP DATE i/tg/oo

Kepler ?cf iufi/ pUccr/J o^ Removed S/N & k4- Ufl.兗>/ JM < 1 4-A w. k: r k.{- Urvri f{l > Installed S/N

3 NIECH INSP DATE

T r /// r/aa

C*-Ppier ec/ / A-*r- Wjfi(w \-lr~f Removed S/N ^2TfA/^O&Oi Installed S/N t^Z>Z T&-JI

MECH INSP DATE

&r

5 /cl-f 6frnbc lAk-f-

R*p ^ced kPi f^robe

Removed S/N Installed S/N

MECH INSP DATE

&T l/ilpO

6 &t-T btkHer^ expired ^epia.crcX E-L-T hotter« Removed S/N O of "n " f 2.3 j J Installed S/N 51M ~ 6?5?7

MECH INSP DATE

IS c AIRWORTHINESS DIRECTIVE COMPLIANCE RECORD

Aircraft Make Cessna Model 172R S/N 17280044 Registration No.

NOOXYZ

-PS.

o to

AD# Effectivity Date

Subject Date & hours @ compliance

Method of Compliance

One tim

e

Recurring

Next com p. @ hrs/date

Authorized signature, cert, type, & number

96-09-10 7/15/96 Oil pumps 1/15/97, 128.7 AD 96-09-10 not applicable to IO-360-L2A engines. No further action required.

X y>M. ΗC±

96-23-03 12/17/96 High pressure fuel pump

1/15/97, 128.7 Previously complied with in accordance with paragraph 2 and service bulletin no. 525A. Mfg. date code does not meet applicable codes listed in AD. No further action required.

X

97-01-03 1/21/97 Piston pins 2/2/97, 140.2 AD 97-01-03 not applicable to NOOXYZ due to serial number range and model affectivity. No further action required.

X

97-12-06 7/15/97 Gascolator, tailpipe, and cowling area

1/20/00, 1140.8 Complied with by modifying cowling in accordance with paragraph (b) and service bulletin no. SB97-2861. No further recurring action required.

X

97-15-11 8/12/97 Piston pins 1/20/00, 1140.8 AD 97-15-11 not applicable to IO-360-L2A engines. No further action required.

X

98-01-01 2/2/98 Static air source valve 1/5/99, 690.5 Previously complied with in accordance with paragraph (b)(2)(i). No further action required.

X

98-13-41 8/18/98 Aileron control cable 7/20/98, 503.2 Previously complied with in accordance with paragraph (2) and service bulletin no. 98-27-02. No further action required.

X

98-17-11 8/28/98 Crankshafts 10/28/98,593.1 AD 98-17-11 not applicable to 10-360-L2A engines. No further action required

X

98-18-12 10/19/98 Torque check inspection

2/20/99, 768.5 Previously complied with in accordance with paragraph (3)(ii). No further recurring action required.

X tt-P izmtspr?

98-25-03 12/18/98 Prevent loss of aileron control caused by a damaged or frayed control cable.

1/5/99, 690.5 98-25-03 not applicable to NOOXYZ due to serial number range and model affectivity. No further action required

X

2

3; 3' 9 c/> en 3" ■8 CD O o'


Airframe maintenance log entry

January 18, 2000 Total time: 1140.8 hours

InstallectEu^placardnjgxjrto right hand fuel filler opening in accordance with Cessna 172R service manual, ^^xsfe-w/ JCS*~K^-,.... A&P. No. 987654321

Brian Thomas

Propeller maintenance log entry

January 18, 2000 Total time: 1140.8 hours; Propeller TSO: 0 hours

Removed propeller-shaft seal and replaced with seal P/N 12D4901 in accordance Cessna service manual section 11-4 through 11-5. Blended 1 /16th inch nick located on the leading edge 6 inches from the base of the #2 blade in accordance with McCauley overhaul manual section 6-11. Post repair dimensional inspection performedHfMccordance with. McCauley overhaul manual section 6-13 and found to be within specificationsg^^Na*^, V*^-^......A&P. No. 987654321

Brian Thomas


January 19, 2000 Total time: 1140.8 hours

Removed emergency locator transmitter battery S/N B89-A-123 and replaced with emergency locator transmitter battery S/N 3924-Q587. ELT operational check acceptable. New ELT battery expires January 20, 2002. Removed left main tire (S/N 4279N00601). Balanced and installed left main tire (Michelin 6.00 x 6, 4 ply tire, S/N 8932TG22). Replaced left strobe light with P/N T2345; opajBtional cheej^good. All work performed in accordance with a Cessna 172R service manual. ^ S ^ ~ ~ ^ f ^ -& P . N o . 9 8 7 6 5 4 3 2 1 Brian Thomas


Figure 17-23. (8 of 9)


Airframe 100-hr log entry

January 20, 2000 Aircraft Total time: 1140.8 hours

Performed 100-hour inspection in accordance with FAR part 43 appendix D and Cessna 172 service manual, section 2-6 through 2-12. Airworthiness Directive compliance may be found in aircraft records. I certify this aircraft has been inspected in accordance with a 100-hour inspection and was determined to be in airworthy condition. jjz>j/an_ u>$ㄒ*^~ A&P. No. 123456789

Beth Collins

Engine 100-hr log entry

January 20, 2000 Aircraft Total time: 1140.8 hours, Engine TSMO: 0 hours

Performed 100-hour inspection in accordance with FAR part 43 appendix D and Cessna 172 service manual, section 2-6 through 2-12. Airworthiness Directive compliance may be found in aircraft records. Compression test results: #1-78/80, #2-79/80, #3- 79/80, #4- 80/80, #5- 79/80, #6-79/80.1 certify this engine has been inspected in accordance with a 100-hour inspection and was determined to be in airworthy condition. yu^?^. C*>1*-- A&P. No. 123456789

Beth Collins

Propeller 100-hr log entry

January 20, 2000 Aircraft Total time: 1140.8 hours, Propeller TSO: 0 hours

Performed 100-hour inspection in accordance with FAR part 43 appendix D and Cessna 172 service manual, section 2-6 through 2-12. Airworthiness Directive compliance may be found in aircraft records. I certify this propeller has been inspected in accordance with a 100-hour inspection and was determined to be in airworthy condition. \P#j&C iLㄒ*^> A&P. No. 123456789

Beth Collins

Figure 17-23. (9 of 9)

AIRCRAFT MAINTENANCE RECORDS

INTRODUCTION Aircraft maintenance records provide evidence that the aircraft conforms to its airworthiness requirements, therefore, incomplete or missing records may render the aircraft unairworthy. Aviation maintenance techni-cians are required to record maintenance entries and aircraft owners are required to maintain them.

To keep the maintenance history of the aircraft, engines, propeller, components, and appliances clear and easy to research, maintenance record entries and inspection entries should be separated. Maintenance and inspection records document dif-ferent events altogether. Individual FARs outline the requirements of maintenance and inspection record entries; Part 43.9 outlines maintenance entry requirements and Part 43.11 outlines inspection entry content. According to FAR Part 43.9, inspec-tion events are specifically excluded from the required maintenance record entries; again, reinforc-ing the idea that maintenance events and inspection events need separate maintenance log entries.

MAINTENANCE RECORD FORM AND CONTENT Except for Air Carrier and some Air Charter opera-tors, technicians who maintain, perform preventive maintenance, rebuild, or alter an aircraft, airframe, aircraft engine, propeller, appliance, or component are required to make an entry in the maintenance record containing the following:

A description of the work performed or refer-ence to FAA acceptable data. The description should describe the work performed so that a person unfamiliar with the work may under-stand what was done, along with the methods and procedures used in performing it. When the work becomes extensive, it could result in a very large record. To prevent this, the rule permits reference to technical data that is acceptable to the FAA in lieu of making the detailed entry. Manufacturer's manuals, ser-vice bulletins, service letters, work orders, air-worthiness directives, advisory circulars, and other acceptable data that accurately describe what was done may be referenced.

• The completion date of the work performed. Normally, this is the date the work was com-pleted. However, the dates may differ when work is accomplished by one person and approved for return to service by another.

• The name of the person performing the work if it is someone other than the person approv ing the return to service.

• The signature, certificate number, and type of certificate held by the person approving the work for return to service. Two signatures may appear in the case of one person performing the work and another returning the aircraft to service, however, a single entry is acceptable.

As discussed earlier, the FARs require the mainte-nance technician to produce maintenance records that contain specific information. The owner, how-ever, is responsible for maintaining records that contain additional information. According to FAR Part 91.417, owners must maintain the following information:

• The total time-in-service of the airframe, engines, propellers, and each rotor. Time in service, with respect to maintenance time records, is defined as the time from the moment an aircraft leaves the surface of the earth until it touches down at the next point of landing. Part 43.9 does not require time in ser vice to be part of maintenance record entries. However, Part 43.11 requires time-in-service to be recorded in the inspection entries under Part 91 and Part 125.

• The status of life-limited parts of each airframe, engine, propeller, rotor, and appli ance. If the total time of the aircraft and the time-in-service of a life-limited part are both recorded in a maintenance entry, then the nor mal record of time-in-service automatically meets this requirement.

• The time since the last overhaul of all items installed on the aircraft which are required to be overhauled on a specified time basis.


Again, if the total time of the aircraft and the time since the last overhaul are both recorded in a maintenance entry, then the normal record of time-in-service automatically meets this requirement.

• The current inspection status of the aircraft, including the time since the last inspection that was required by the inspection program under which the aircraft and its appliances are maintained.

• The status of applicable airworthiness direc tives [AD] including the method of compli ance, the AD number, revision date, whether or not the AD involves recurring action, and, if applicable, the time and date when the next action is required.

• Copies of FAA Form 337 for each major alter ation to the airframe and currently installed engines, rotors, propellers, and appliances.

The list of information that the owner must main-tain varies from the list of information that the maintenance technician must record. Although the technician is not required to record the above listed information, thorough technicians include it in the maintenance logbook entries. Figure 17-24 and fig-ure 17-25 illustrate typical maintenance record entries. [Figure 17-24] [Figure 17-25]

Figure 17-24. Sample entryaintenance record entry regarding the replacement of a vacuum pump and entered in the airframe log.

January 18, 2000 Total time 1245.7 Removed emergency locator transmitter (ELT) battery S/N 234-345Q and replaced with emergency locator transmitter battery P/N TL342, S/N 34AQ456 in accordance with Piper service manual page C23-24. Functional check good. ELT replacement due on January 18, 2002. fl/yUA TTBf&^P no. 23456766 John D. Brown

Figure 17-25. Sample entryaintenance record entry regarding the ELT battery replacement recorded in the air-frame log.

Aircraft owners are not required to keep separate logbooks for the airframe, engines, propellers, or appliances; however, most do. Most owners, who operate under Part 91 rules, maintain airframe, engine, and propeller logs. This practice helps in the research and tracking of the aircraft history, time-limited items, inspection times, airworthiness directive compliance, etc. The maintenance techni-cian must know where to record specific types of maintenance and inspection information. For exam-ple, an engine oil and filter change would be recorded as a maintenance entry in the engine log-book. However, the repair of the exhaust system would be recorded as a maintenance entry in the airframe logbook.

INSPECTION RECORD FORM AND CONTENT Before any inspection is considered complete, the inspection record entry must be recorded in the air-craft's maintenance records. The inspection record requirements of FAR Part 43.11 apply to the annual, 100-hour, and progressive inspections under Part 91. FAR Part 43.11 also applies to inspection pro-grams under Part 125, approved aircraft inspection programs (AAIP) under Part 135 and the 100-hour and annual inspections under Part 135.411. Inspections performed on transport category aircraft require record entries outlined in FAR Part 121.709.

According to FAR Part 43.11, the person approving or disapproving for return-to-service the aircraft, or any item after any inspection, is required to make an entry in the maintenance record containing the fol-lowing information:

• The type of inspection and a brief description of the extent of the inspection.

• The date the inspection was completed.

• The aircraft total time-in-service.

• Certification statement. • The signature, the certificate number, and the

type of certificate held by the person approv ing or disapproving the aircraft for return to service.

• If an inspection is conducted under an program that is allowed in Part 91,123,125, or 135, such as Progressive or Approved Aircraft Inspection Programs (AAIP), then the logbook entry must identify the inspection program, the part of the inspection program that was accomplished, and also contain a statement that the inspection was performed in accordance with the proce dures for that particular program.


In addition, if the person performing any inspection that is required by Part 91,125, or 135 should find the aircraft unairworthy, the inspector must provide the owner with a signed and dated list of discrepancies. When a discrepancy list is provided to an owner, it basically means that, with the exception of the listed discrepancies, the aircraft inspected is airworthy. When an inspection is terminated before it is com-pleted, the maintenance record must clearly indicate that the inspection was discontinued. Although it is no longer required to forward a copy of the discrep-ancy list to the local flight standards district office (FSDO), it becomes part of the maintenance record and the owner is responsible for maintaining it accordingly. The inspection entry must reference the discrepancy list if one is provided to the owner.

Many times, discrepancies that are found during inspections are repaired and signed off as the inspection progresses. In this circumstance, a list of discrepancies is not needed and the inspection may be signed off as being airworthy. In the case of a 100-hour inspection, while the certified mechanic inspects the aircraft, another certified mechanic may repair and sign off any discrepancies prior to the completion of the inspection. In this case, maintenance record entries are produced regarding the repairs and separate entries are produced documenting the inspection. Keeping the maintenance entries and inspection entries separate helps keep the aircraft logs clear and easy to follow.

If the owner maintains separate records for the air-frame, engines, and propellers, the entry for the 100-hour inspection is entered in each, while the annual inspection is only required to be entered into the airframe record.

ANNUAL INSPECTION ENTRIES An annual inspection may be signed off in the main-tenance records as airworthy or unairworthy depending on the condition of the aircraft. Whether or not the aircraft owner keeps separate logs, FARs stipulate the annual inspection need only be recorded in the airframe logbook. However, it is good practice to enter an annual inspection record in all maintenance logbooks making maintenance information easier to research and compile. Figure 17-26 illustrates a typical annual inspection entry regarding an airworthy aircraft. [Figure 17-26]

Figure 17-27 represents an unairworthy annual inspection entry. In addition, a list of discrepancies outlining the unairworthy items found during the inspection must be provided to the aircraft owner and referenced in the inspection record. [Figure 17-27] [Figure 17-28]

September 27, 2000 Total time: 2780 hours Performed an annual inspection in accordance with FAR part 43 appendix D and manufacturer's maintenance manual, section 2-1 through 2-11. Airworthiness Directive compliance may be found in aircraft records. I certify that this aircraft has been inspected in accordance with an annual inspection and was determined to be Jn airworthy condition.

A. No. 13453234

Figure 17-26. Sample entryirworthy annual inspection.

Total time: 3245 hours Performed an annual inspection in accordance with FAR part 43 appendix D and Cessna 172G service manual, section 2-1 through 2-11. Airworthiness Directive compliance may be found in aircraft records. I certify that this aircraft has been inspected in accordance with an annual inspection and a list of discrepancies and unairworhty items dated May 12, 2000 has been provided to the

aircraft owner. d/t I.A. No. 13453234

Figure 17-27. Sample entrynairworthy annual inspection entry.

May 12,2000 Ms. Rhonda Jones 1234 W. 1st St. Denver, CO 23456 Re; Unairworthy items found during annual inspection

Dear Ms. Jones, This letter is to certify that on April 10, 2000,1 completed a 100-hour inspection on your Cessna 172F, N I23BC, and found it to be in an unairworthy condition for the following reasons:

1) Compression in cylinder #4 read 40/80, which is below the manufacturer's recommended limits.

2) A 1/Sth inch nick was found on the leading edge of the propeller.

Your aircraft will be considered airworthy when the above listed discrepancies are corrected and approved for return to

service by a person authorized in FAR part 43. Thank you.

May 12, 2000

JoeL. Smith, A&P no. 13453234 Aviation Services Inc. 1234 2nd Ave. Denver, CO 23456

Figure 17-28. Typical letter to aircraft owner itemizing the discrepancies found during an annual inspection.


100-HOUR INSPECTION ENTRIES A 100-hour inspection may also be signed off in the maintenance records as airworthy or unairworthy. The required inspection entry items are listed in FAR Part 43.11. If the aircraft owner maintains sep-arate logs, the 100-hour inspection must be recorded in each applicable maintenance log unlike the annual, which is only required to be recorded in the airframe logbook. Figure 17-29 and Figure 17-30 illustrate airworthy and unairworthy 100-hour inspection entries. [Figure 17-29] [Figure 17-30]

Total time: 1459 hours Performed 100-hour inspection in accordance with FAR part 43 appendix D and manufacturer's maintenance manual, section B1 through B10. Airworthiness Directive compliance may be found in aircraft records. I certify that this aircraft has been inspected in accordance with a 100-hour inspection and was determined to be in airworthy

condition. 3. No. 1347890

January 5, 2000 Total time: 540 Performed progressive inspection in accordance with FAR part 43 appendix D and Cessna 421G service manual page 2-1 through 2-10. Airworthiness directive compliance may be found in aircraft records. I certify that in accordance with a progressive inspection program, a routine inspection of the left wing and a detailed inspection of the right hand engine were performed and the aircraft is approved for return to service.

A&Pno. 1589432

Figure 17-31 . Sample entryrogressive inspection entry.

Total time: 4567 hours Performed a phase 3 inspection in accordance with the StarJet Charter approved inspection manual, section 3-1 to 3-16. Airworthiness Directive compliance may be found in aircraft records. I certify that this aircraft has been inspected in accordance with an Approved Aircraft Inspection Program and was determined to be in airworthy condition.

A&P. No. 1347890

Performed 100-hour inspection in accordance with FAR part 43 appendix D and manufacturer's maintenance manual, section B1 through B10. Airworthiness Directive compliance may be found in aircraft records. I certify that this aircraft has been inspected in accordance with a 100-hour inspection and a list of discrepancies and unairworthy items dated April 10, 2000 has been provided for the aircraft owner.

Figure 17-30. Sample entrynairworthy 100-hr inspection record entry.

PROGRESSIVE INSPECTION & APPROVED AIRCRAFT INSPECTION PROGRAM (AAIP) ENTRIES FAR Part 43.11(a)(7), which refers to inspection pro-grams such as AAIPs and progressive inspections, now requires a more specific statement than previ-ously required. The entry must identify the inspec-tion program used, identify the portion or segment of the inspection program accomplished, and con-tain a statement that the inspection was performed in accordance with instructions and procedures for that particular program. Samples of a progressive inspection entry and an AAIP inspection entry fol-low. [Figure 17-31] [Figure 17-32 ]

Figure 17-32 . Sample entrypproved Aircraft Inspection Program (AAIP) entry.

AIRWORTHINESS DIRECTIVE COMPLIANCE ENTRIES Although it is the owner's primary responsibility to maintain their aircraft in an airworthy condition, including airworthiness directive compliance, maintenance professionals may also have direct responsibility for AD compliance. When 100-hour, annual, or progressive inspections are performed on an aircraft, the technician performing the inspection is required to determine that all applicable airwor-thiness requirements are met, including the compli-ance of any applicable airworthiness directives.

When airworthiness directives are accomplished, maintenance personnel are required to include the completion date, name of the person complying with the AD, signature, certificate number, and kind of certificate held by the person approving the work, and the current status of the applicable "AD" in the maintenance record entry. The owner is required by FAR Part 91.417 to maintain AD compliance infor-mation including the current status of the AD along with the method of compliance, the AD number, and revision date and, if the AD is recurring, the time and date when the next action is required.

June 30, 2000

Figure 17-29. Sample entryirworthy 100-hr inspection record entry.

April 10, 2000 Total time: 1002 hours

October 6, 2000


The recording of the airworthiness directive compli-ance may either be recorded in the maintenance log-book and/or kept as a separate listing in the mainte-nance records in the form of a running AD log.

Figure 17-33 illustrates an AD listing format that keeps track of all ADs complied with on a specific aircraft. [Figure 17-33] [Figure 17-34] [Figure 17-35]

Aircraft total time 2345.5 Performed visual inspection of the flap sector upper mounting brackets in compliance with AD 99-22-05 paragraph A and Gates Learjet airplane modification kit 55-86-2. No cracks found upon inspection. Replacement of flap upper mounting brackets due at 2398.5TT in accordance with paragraph (A)(2).

May 2, 2000 1449.2 Total time; 151.3 TSMO Performed visual inspection of the oil adapter locking nut installation in accordance with AD 96-12-22 paragraph (2)(a)(1). Correct torque noted and no oil leakage found upon inspection. Next inspection due at 1539.2 hours or when the engine oil filter is removed, whichever occurs

first, " ' -f -—

A. 123456789

Figure 17-33. Sample entryirworthiness directive (AD) compliance logbook entry regarding an AD that required an inspection and subsequent repair within 100 flight hours of the effective date of the AD and recorded in the airframe logbook.

Figure 17-34. Sample entryD compliance maintenance entry regarding a recurring AD entered in the engine log-book.

Figure 17-35. Sample airworthiness directive (AD) record listing.

June 30,1987

chapter 17 aircraft airworthiness inspection

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