Module 7 (Maintenance Practices) Sub Module 7.20 (Maintenance Procedures).pdf

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PIA TRAINING CENTRE (PTC) Module 7 - MAINTENANCE PRACTICES Category A/B1 Sub Module 7.20 - Maintenance Procedures

PTC/CM/B1.1 Basic/M7/04 Rev. 00 7.20 Mar 2014

MODULE 7

Sub Module 7.20

MAINTENANCE PROCEDURES



PTC/CM/B1.1 Basic/M7/04 Rev. 00 7.20 - i Mar 2014

Contents

MAINTENANCE PROCEDURES --------------------------------------------------- 1

MAINTENANCE PLANNING ------------------------------------------------------- 1

MODIFICATION PROCEDURES --------------------------------------------------- 1

STORES PROCEDURES ------------------------------------------------------------- 2

CERTIFICATION PROCEDURES --------------------------------------------------- 3

INTERFACE WITH AIRCRAFT OPERATION ------------------------------------- 3

ADDITIONAL MAINTENANCE PROCEDURES ---------------------------------- 5

CONTROL OF LIFE LIMITED COMPONENTS ----------------------------------- 5



PTC/CM/B1.1 Basic/M7/04 Rev. 00 7.20 - 1 Mar 2014

MAINTENANCE PROCEDURES An aircraft has to receive regular maintenance, of varying depths to remain fully airworthy at all times. This is achieved in most circumstances by making various checks, at intervals, throughout the life of the aircraft. These intervals can be stated in quantities of flying hours, calendar time or combinations of the two systems. MAINTENANCE PLANNING The periods of maintenance can be small or large. The aircraft can be in for a short period of maintenance over-night (or perhaps no longer than two days), whilst, on a large maintenance period, the aircraft might be in the hangar for a week or two, depending on the type of aircraft. It is normal to apply what is known as a back-stop to each period for safety. For example, if the frequency of each maintenance action is every 100 flying hours, then there will probably be a calendar back-stop of one month. This means that if the aircraft is only flown for 25 hours during one month, then it will have its maintenance done on the last day of that month, regardless if its low hours. Equally, if the aircraft is intensively flown day-and-night, it might reach its 100 hours after 19 days. It will then receive its maintenance at that time, as a result of its intensive flying. The decision as to the frequency and depth of this maintenance is controlled by the Type Design Organization, the organization which designed the aircraft.

The maintenance program contains a list of the most significant items and recommendations as to the maintenance actions, recommended frequencies and sampling/inspection points. It will also contain a program that monitors engine critical parts and the inspections to be done on those parts. All aircraft have a list of critical parts, with which it cannot fly without them being serviceable, or which can be dispensed with, providing other parts can cover for the missing part. MODIFICATION PROCEDURES Modifications are changes made to a particular aircraft, including all its components, engines, propellers, radio apparatus, accessories, instruments, equipment and their respective installations. With the exception of modifications which the NAA agree to be of such a minor nature that airworthiness is unaffected, all modifications must be approved in accordance with the relevant parts of EASA regulations. The modifications are approved by the NAA or by the Approved Organization carrying out the modification program. Modifications must be such that the design of the aircraft, when modified, complies at least with the requirements which applied when the aircraft was originally certified.




When a modification is being designed, a decision has to be made as to whether the modification is to be classified as Minor or Major. The installing of a new type of engine would most definitely be a major modification, whilst changing the type of clips holding cables together would be a minor one. It is somewhere in the middle when the decision as to the grading of a modification has to be decided by the NAA. Major modifications The organization request approval from NAA and, when approved, an approval note is returned to the organization. This allows the modification to be embodied. Minor modifications The organization writes to the NAA, requesting permission to embody the modification and, when approved, the NAA sends a form, back, to permit embodiment. If the organization has NAA approval, it is permitted to approve its own modifications. All the organization has to do is to keep full records of the design and embodiment of the modification. All modifications are recorded in the aircraft documentation, either inside the Airframe Log Book, if the aircraft weighs less than 2730 kg or in a separate Modification Record Book if the aircraft weighs more than 2730 kg.

STORES PROCEDURES All aircraft and component manufacturing and maintenance establishments will have a stores department, whose object is twofold. Its purpose, firstly, is to ensure that all materials, parts, components etc. used on aircraft are to the correct specification. The second purpose of the stores is to enable the history of any important part to be traced back to its original manufacture and its raw materials. All stores transactions use the same forms throughout the EASA system as well as the USA and Canada. This system ensures that a store in one part of this country will receive a component from within the UK, all EASA countries or North America on the same form. This is known throughout the EASA system as the EASA Form 1. Stores that operate within an organization that is approved by the NAA to operate, with little control or supervision from the NAA, is known as an Approved Stores. An Approved Store will contain three main departments:

1. A quarantine store, which accepts items from other companies and checks that they are satisfactory.

2. A bonded store which takes items from the quarantine store, after approval, and, when requested, issues those components to the servicing technicians.

3. An office or administration centre, which keeps adequate files and records, to enable cross-checking of any transaction through the store system.




CERTIFICATION PROCEDURES Any maintenance done on an aircraft that has a Certificate of Airworthiness (C of A) has to be certified by the technician(s) doing the work. Depending on the company they work for, the technicians can have either personal certification or approval by their own company. The legal requirement is quoted as: An aircraft shall not fly unless there is in force a Certificate of Release to Service issued in respect of any overhauls, modifications, repairs or maintenance to the aircraft or its equipment. Normally the work is either certified by an approved engineer or, completed by a non-approved engineer and certified by another, approved engineer. This certification is known as a Certificate of Release to Service. The wording on the document for signature is to a standard format and certifies that the work has been done in accordance with EASA 145 and that the aircraft is fit for release back to service. The certification should also contain particulars of the work done or the inspection completed and the organization and place at which the work was done. It is also required that the aircraft type and registration or component type, part and serial number shall be recorded as applicable. There are a number of minor maintenance operations that do not require certification/ release to service. This can include minor maintenance, done by the pilot, on a small private aircraft.

INTERFACE WITH AIRCRAFT OPERATION There are many links between aircraft maintenance and the flying done by both commercial and private operations. These links, or interfaces, include the legislation that dictates how the two operations are to work together. For the larger commercial companies, all the legislation is currently laid down under JAR-OPS, produced by the JAA JAR-OPS controls many facets of commercial flying. This can include how the company maintains its aircraft, (or how it sub-contracts the work elsewhere); how the documentation and publications record all the information needed for both the engineers and the flight crew and how the quality of the whole operation is kept to an acceptable standard. The communication of information between maintenance and flying personnel is normally via a number of different publications such as:

I. The Technical Log Book (Tech. Log) II. The Log Books (Aircraft, Engine and Propeller)

III. The Modification Records. The Tech. Log contains all details of the sector by sector flight operations, such as flight times, defects, fuel (on arrival and uplifted), other ground maintenance and replenishments. The Log Books are usually kept within the records department, but they are a long term record of not only the total flying hours, but of the life remaining on engines and propellers and the maintenance checks done on the aircraft.




The Modification Records allow all to see what changes, (modifications), have been embodied to the aircraft. These changes might require different flight operations or maintenance actions than prior to their embodiment. MAINTENANCE INSPECTION/ QUALITY CONTROL/ QUALITY ASSURANCE All maintenance done on the aircraft, from the Pre-Departure Inspection (made before every flight); to the heavy Check D inspection (done every four to six years), is controlled from the Maintenance Schedule. This publication is produced by the aircraft manufacturer, and dictates the depth and frequency of work at which each inspection is completed. On light aircraft, the maintenance is normally done in accordance with a Schedule produced by the CAA, called the Light Aircraft Maintenance Schedule, (LAMS). This is a simple schedule, common to all private aircraft below 2730kg, which divides the maintenance into 50 and 150 flying hour, annual and tri-annual inspections. The personnel who do any of the inspections have to be either licensed by the CAA or approved by their own company, (if the company is itself approved by the CAA). The types of aircraft being serviced, and their use, will control which type of qualification they require.

If a company has CAA approval under JAR-145, it is permitted to control all of the maintenance it does as well as, in some instances (with the additional approval under JAR-147), the in house training of its own engineers. An approved company has to introduce a Quality Assurance Department, to the strict rules laid down in JAR-145. This department controls the standards of the company from the lowliest worker on the hangar floor to the Accountable Manager, usually the managing director. It is responsible for all of the engineers and their approvals. It also examines engineers and trainees, prior to their examination by the CAA. The Quality department also makes audits throughout the company, at intervals, to ensure all the procedures, laid down in the company manuals, are being followed. When certain operations are being done on an aircraft, whereby there might be catastrophic consequences to the aircraft if the work was not done correctly, then a duplicate inspection is required. This involves two engineers; one of whom completes the work while the second (who has had nothing to do with the task), checks the work and signs that it has been completed correctly.




ADDITIONAL MAINTENANCE PROCEDURES Apart from the regular maintenance checks, listed in the Maintenance Manual, there are a number of additional maintenance procedures that are done at irregular intervals. These could include washing the aircraft, de-icing it in the winter, weighing it after certain operations and painting it when its condition warrants it. The information and the correct procedures will probably be found in the maintenance manuals. (Under Washing, De-icing, Weighing and Painting). Other work done, in addition to the normal regular maintenance, might include an on-going sampling program or condition monitoring, which is done during the normal day-to-day operation of the aircraft. These tasks would probably be organized at the request of the local CAA office, to comply with an airworthiness request from the manufacturer. CONTROL OF LIFE LIMITED COMPONENTS On almost any aircraft, there will be a number of components that have a stated life, usually quoted in flying hours, cycles, calendar time or operating hours. The correct terminology for life is Mandatory Life Limitation. The components will have been given a life for various reasons. For example, a fatigue life on a structural component in flying hours; the landing gear legs due for retirement after 10,000 landings, the batteries due for replacement after 3 or 4 months and a retirement life on an APU measured in hours running time.

The control of the replacement of components, on completion of their lives, rests with the Technical Control/Records department, which monitors all of the aircraft documents. When an item is due for replacement, the work is often synchronised with a scheduled maintenance check, so that the aircraft is out of service for the minimum amount of time. It is normal, however, for small items such as batteries, to be changed on the flight line, often at the end of the days flying, with the battery replacement being done at the same time as the daily inspection. The notification of the correct day for the replacement will be annotated on a document called the Maintenance Statement, which gives all items due for replacement, in between scheduled maintenance checks. In the front of the Maintenance Manual is a chapter, variously entitled Retirement Lives; Long Life Items or Fatigue Lives. This chapter lists the retirement lives of many components and parts with long lives, which can include such items as engine hot-end components, landing gear legs and major structural items that have retirement lives in the thousands of flying hours/cycles. This list will be monitored by the Technical Records department, and the aircraft documents will be annotated and the work cards etc., raised when the task is required to be done.




INSPECTION FUNDAMENTALS GENERAL Inspections are visual examinations and manual checks to determine the condition of an aircraft or component. An aircraft inspection can range from a casual walk around to a detailed inspection involving complete disassembly and the use of complex inspection aids. An inspection system consists of several processes, including: (1) Reports made by mechanics or by the pilot or crew flying an aircraft and (2) regularly scheduled inspections of an aircraft. An inspection system is designed to maintain an aircraft in the best possible condition. Thorough and repeated inspections must be considered the backbone of a good maintenance program. Irregular and haphazard inspection will invariably result in gradual and certain deterioration of an aircraft. The time which must eventually be spent in repairing an aircraft thus abused often totals far more than any time saved in hurrying through routine inspections and maintenance. It has been proven that regularly scheduled inspections and preventive maintenance assure airworthiness. Operating failures and malfunctions of equipment are appreciably reduced if excessive wear or minor defects are detected and the proper use of records concerning these inspections cannot be overemphasized.

Airframe and engine inspections may range from preflight inspections to detailed inspections. The time intervals for the inspection periods vary with the models of aircraft involved and the types of operations being conducted. The airframe and engine manufacturer's instructions should be consulted when establishing inspection intervals. Aircraft may be inspected using flight hours as a basis for scheduling, or on a calendar inspection system. Under the calendar inspection system, the appropriate inspection is performed on the expiration of a specified number of calendar weeks. The calendar inspection system is an efficient system from a maintenance management standpoint. Scheduled replacement of components with stated hourly operating limitations is normally accomplished during the calendar inspection falling nearest the hourly limitation. In some instances, a flight-hour limitation is established to limit the number of hours that may be flown during the calendar interval. Aircraft operating under the flight-hour system are inspected when a specified number of flight hours are accumulated. Components with stated hourly operating limitations are normally replaced during the inspection that falls nearest the hourly limitation.




REQUIRED INSPECTIONS Federal Aviation Regulations (FAR) provide for the inspection of all civil aircraft at specific intervals, depending generally upon the type of operations in which they are engaged, for the purpose of determining their overall condition. Some aircraft must be inspected at least once each 12 calendar months, while inspection is required for others after each 100 hours of flight. In other instances, an aircraft may be inspected in accordance with an inspection system set up to provide for total inspection of the aircraft over a calendar or flight-time period. In order to determine the specific inspection requirements and rules for the performance of inspections, reference should be made to the Federal Aviation Regulations which prescribe the requirements for the inspection and maintenance of aircraft in various types of operations. INSPECTION TECHNIQUES Before starting an inspection, be certain all plates, access doors, fairings, and cowling have been opened or removed and the structure cleaned. When opening inspection plates and cowling, and before cleaning the area take note of any oil or other evidence of fluid leakage.

CHECKLIST Always use a checklist when performing the inspection. The checklist may be of your own design, one provided by the manufacturer of the equipment being inspected, or one obtained from some other source. The checklist should include the following: 1. Fuselage and hull group

a. Fabric and skinfor deterioration, distortion, other evidence of failure, and defective or insecure attachment of fittings.

b. Systems and componentsfor proper installation, apparent defects, and satisfactory operation.

c. Envelope gas bags, ballast tanks, and related partsfor

condition. 2. Cabin and cockpit group

a. Generallyfor cleanness and loose equipment that

should be secured.

b. Seats and safety beltsfor condition and security.

c. Windows and windshieldsfor deterioration and breakage.

d. Instrumentfor condition, mounting, marking, and (where

practicable) for proper operation.




e. Flight and engine controlsfor proper installation and

operation.

f. Batteriesfor proper installation, and charge.

g. All systemsfor proper installation, general condition, apparent defects, and security of attachment.

3. Engine and nacelle group

a. Engine sectionfor visual evidence of excessive oil, fuel,

or hydraulic leaks, and sources of such leaks.

b. Studs and nutsfor proper torquing and obvious defects.

c. Internal enginefor cylinder compression and for metal particles or foreign matter on screens and sump drain plugs. If cylinder compression is weak, check for improper internal condition and improper internal tolerances.

d. Engines mountfor cracks, looseness of mounting, and

looseness of engine to mount.

e. Flexible vibration dampenersfor condition and deterioration.

f. Engine controlsfor defects proper travel, and proper

safetying.

g. Lines, hoses, and clampsfor leaks, condition, and looseness.

h. Exhaust stacksfor cracks, defects, and proper

attachment. i. Accessoriesfor apparent defects in security of

mounting.

j. All systemsfor proper installation, general condition defects, and secure attachment.

k. Cowlingfor cracks and defects.

l. Ground run-up and functional check check all power

plant controls and systems for correct response, all instruments for proper operation and indication.

4. Landing gear group

a. All unitsfor condition and security of attachment.

b. Shock absorbing devicesfor proper oleo fluid level.

c. Linkage, trusses, and membersfor undue or excessive

wear, fatigue, and distortion.

d. Retracting and locking mechanism for proper operation.

e. Hydraulic linesfor leakage. e. Electrical systemfor chafing and proper operation of

switches.




g. Wheelsfor cracks defects, and condition of bearings.

h. Tiresfor wear and cuts. i. Brakesfor proper adjustment.

j. Floats and skisfor security of attachment and obvious

defects.

5. Wing and center section

a. All componentsfor condition and security.

b. Fabric and skinfor deterioration, distortion, other evidence of failure, and security of attachment. d. Internal structure (spars, ribs compression members)

for cracks, bends, and security. e. Movable surfacesfor damage or obvious defects,

unsatisfactory fabric or skin attachment and proper travel.

f. Control mechanismfor freedom of movement,

alignment, and security.

g. Control cablesfor proper tension, fraying, wear and proper routing through fairleads and pulleys.

6. Empennage group

a. Fixed surfacesfor damage or obvious defects, loose

fasteners, and security of attachment.

b. Movable control surfacesfor damage or obvious defects, loose fasteners, loose fabric, or skin distortion.

c. Fabric or skinfor abrasion, tears, cuts or defects,

distortion, and deterioration.

7. Propeller group

a. Propeller assemblyfor cracks, nicks, bends, and oil leakage.

b. Boltsfor proper torquing, and safetying

c. Anti-icing devicesfor proper operations and obvious

defects.

d. Control mechanismsfor proper operation, secure mounting, and travel.

8. Communication and navigation group

a. Radio and electronic equipmentfor proper installation

and secure mounting.

b. Wiring and conduitsfor proper routing, secure mounting, and obvious defects.




c. Bonding and shieldingfor proper installation and

condition.

d. Antennasfor condition, secure mounting and proper operation.

9. Miscellaneous

a. Emergency and first-aid equipmentfor general condition

and proper stowage.

b. Parachutes, life rafts, flares, etc. inspect in accordance with the manufacturer's recommendations.

c. Autopilot systemfor general condition, security of

attachment, and proper operation.

AIRCRAFT LOGS "Aircraft logs" as used in this handbook is an inclusive term which applies to the aircraft logbook and all supplemental records concerned with the aircraft. The logs and records provide a history of maintenance and operation, control of maintenance schedules, and data for time replacements of components or accessories. The aircraft logbook is the record in which all data concerning the aircraft is recorded. Information gathered in this log is used to determine the aircraft condition, date of inspections, time on airframe and engines. It reflects a history of all significant events occurring to the aircraft, its components, and accessories, and provides a place for indicating compliance with FAA Airworthiness Directives or manufacturers' service bulletins. PUBLICATIONS Aeronautical publications are the sources of information for guiding aviation mechanics in the operation and maintenance of aircraft and related equipment. The proper use of these publications will greatly aid in the efficient operation and maintenance of all aircraft. These include manufacturers' service bulletins, manuals, and catalogs, as well as FAA regulations, airworthiness directives, advisory circulars, and aircrafts, engine and propeller specifications.




Bulletins Service bulletins are one of several types of publications issued by airframe, engine, and component manufacturers. The bulletins may include: (1) The purpose for issuing the publication; (2) the name of the applicable airframe, engine, or component; (3) detailed instructions for service, adjustment, modification or inspection, and source of parts, if required; and (4) the estimated number of man hours required to accomplish the job. Maintenance Manual The aircraft maintenance manual provided by the manufacturer contains complete instructions for maintenance of all systems and components installed in the aircraft. It contains information for the mechanic who normally works on units, assemblies, and systems, while they are installed in the aircraft, and not for the overhaul mechanic. A typical aircraft maintenance manual contains: (1) A description of the systems such as electrical, hydraulic, fuel, control, etc.; (2) lubrication instructions setting forth the frequency and the lubricants and fluids which are to be used in the various systems; (3) pressures and electrical loads applicable to the various systems; (4) tolerances and adjustments necessary to proper functioning of the airplane; (5) methods of leveling, raising, and towing; (6) methods of balancing control surfaces; (7) identification of primary and secondary structures; (8) frequency and extent of inspections necessary to the proper operation of the airplane; (9) special repair methods applicable to the airplane; (10) special inspection techniques requiring X-ray, ultrasonic, or magnetic

particles inspection; and (11) a list of special tools. Overhaul Manual The manufacturer's overhaul manual contains brief descriptive information and detailed step-by-step instructions covering work normally performed on a unit away from the aircraft. Simple inexpensive items, such as switches and relays, on which overhaul is uneconomical, are not covered in the overhaul manual. MAINTENANCE PROCEDURES Continued airworthiness would need an operator certification. The men who work on the aircraft for the purpose of certification have to qualify for a license or approval. And other certificate known as certificate of approval is required by the authorities to an organization which complies with the laid down requirements for an approved organization. A maintenance program is selected in conformity with the requirements of various certificates for the purpose of continuous airworthiness. The maintenance program is chalked out on the concept of the periodic maintenance processes. Maintenance: The actions required for restoring or maintaining an item in serviceable condition.




Maintenance Schedule The aircraft for which a Certificate of Airworthiness is in force shall be maintained in Airworthy condition. All the maintenance on the aircraft shall be carried out in accordance with the approved maintenance schedule. Preventive Maintenance or Scheduled Maintenance or Routine Maintenance. The maintenance performed at definite intervals to retain an item in a serviceable condition by systematic inspection, detection, replacement of worn items. Adjustments, calibration, cleaning etc. it involved simple or minor preventive operations and replacements of those parts which do not involve complex assembly or operation for example removal installation of tires, brake assemblies, replenishing hydraulic fluids. Line Maintenance It is the maintenance consisting of routine tasks with low intervals like servicing, cleaning, refueling and some inspections. The non routine line maintenance ranges from the removal / installation of Black boxes to removal/installation of engine. Line maintenance is "departure oriented" and any time consuming items are deferred to next base visit.

Base Maintenance It involves routine maintenance tasks with higher intervals. Base Maintenance requires proper facilities and place to carry out heavy maintenance tasks. MAINTENANCE CHECKS 1. Service Checks

These checks are performed after each flight, at the

end of a day of flight operations, and/or before first flight of the day.

These checks are usually referred to as transit check, turn around check, lay over check, pre-flight check or simply as service check.

These checks involve minor checks, defect rectification. (Pireps/Maint.)

2. 'A', 'B', 'C', Checks

These checks are performed at their scheduled interval,

usually after 100 to 3000 flying hours. These checks demand longer grounding time depending on the type of aircraft and the type of operations involved.

They have lesser frequency as compared to service checks.




These checks are cumulative, that is, all the lower

checks are concurrently performed with these major checks.

3. D Check or Heavy Maintenance

This is the longest interval check and is performed after three to five years of operation. Checks with lesser frequency require more grounding time.

This check involves internal structural inspections, cabin refurbishment, paint renewal etc.

This check is cumulative, that is, all the lower checks are

concurrently performed with this major check. Aircraft is completely overhauled.

PRIMARY MAINTENANCE PROCESSES 1. On Condition This is also a preventive process but one in which the items inspected or tested at the periods in order to determining whether it can continue in service. The fundamental purpose of the 'on condition maintenance process' is to remove an item before its failure in service. On condition process does not mean the 'fit it and forget it' philosophy. On condition maintenance is restricted to those units or systems or portions of the structure on which a determination of condition can be made by repetitive inspections or tests. This necessarily mean a careful scrutiny and examination of items through visual or non destructive aids to ensure that the condition is satisfactory at the time of inspection and shall remain satisfactory till next inspection is due. It is important that these inspections are repeated at the regular intervals. The length of the interval is fairly short at the beginning and then gradually increasing as service experience is becoming available. When on condition items exceed the limit and not considered satisfactory they are removed and sent to shop for overhaul.




2. Condition Monitoring The condition monitoring is not a preventive maintenance process. It does not have a hard time non or condition elements. It is the one which information on item condition gained from operational experience is collected, analyze and interpreted on a continuing basis as a means of implementing corrective procedures thereby resulting in modifications and maintenance program changes. In other words it is a statically controlled process. The condition monitoring is the only maintenance process in which failure or malfunction is allowed to occur, but only nominated failure. The condition monitoring is applicable only to items whose functions do not require a preventive maintenance to ensure operating safety. On condition items are subjected to periodic inspection to determining the extent of the deterioration in performance and are removed when they cross that point and sent to shop for overhaul. Hard Time and On Condition items are airworthy and safe items. Condition monitored items are those which do not relate to safety. They are redundant being more than one.

4. Hard Time This is a preventive process in which the known deterioration of an item is limited to an acceptable level by the maintenance action carried out at time related periods. For example number of landings, number of cycles, Calendar time. The maintenance action normally done is servicing, overhaul or replacement in accordance with methods prescribed in relevant manual, so that the item concerned is either replaced or restored to such a condition that it can be released for service for a further specified period. The individual hard times are determined by the manufacturer during testing processes or by the airline as a result of its operation experience. The hard time intervals usually apply to the total life of the parts or to the overhaul of the items. Nowadays hard time items rarely make up more than 2% or 3% of all scheduled maintenance tasks. Flap links and landing gear parts are typical hard time replacement items. The hard time maintenance is the oldest and best known primary maintenance process and its requirement is drastically reduced as the aircraft technology and design criteria have moved from fabric covered bi-planes to wide-body jets.




AIRCRAFT MAINTENANCE DOCUMENTS FOR CONTINUED AIRWORTHINESS Certificate of Release to Service A certificate of Release to Service shall be issued after accomplishment of inspections, repairs, replacements, modifications overhaul & scheduled Maintenance Tasks on the aircraft / equipment in accordance with the requirements of Airworthiness Directorate, CAA (Pak) / Joint Aviation Requirements (JAR 145) and Instructions of the Manufacturer. According to the requirements this certificate will be signed by;

a: Appropriately Licensed Aircraft Maintenance Engineer,

b: Person(s) approved by the Airworthiness Directorate as competent to issue such certificate;

c: Person(s) authorized by an organization approved by the Airworthiness Directorate to ssue such certificate.

Certificate of Maintenance Review This certificate ensures that;

a: All maintenance specified in the approved Maintenance Schedule has been carried out.

b: All modifications & inspections classified as mandatory by Airworthiness Directorate have been earned out;

c: All the defects recorded in the Technical Log have been rectified or deferred in accordance with CAA approved procedure;

d: All certificates Release to Service required have been issued.

Certificate of Maintenance Review will be signed by the following who have at least eight years of experience of aircraft maintenance which includes at least two years recent experience involving certification of Maintenance.

1. Appropriately Licensed Aircraft Maintenance Engineer holding at least two categories in the appropriate sub division (Other than category-X, DR Compass) of the particular aircraft type.

2. Person(s) authroized by Airworthiness Directorate competent to issue such certificate.

Certificate of Fitness for Flight This Certificate will be issued prior to TEST FLIGHT. This Certificate will be signed by AMEs/Persons authorized by Airworthiness Directorate to sign Certificate of Maintenance Review. It will be valid for a period not exceeding seven days from the issue date. The certificate will be issued in duplicate. One Copy will be carried.




APPROVED STORES Quarantine Store The quarantine store is the input side of an approved store. All incoming parts and raw material is held until proved to conform to specification. Component parts are given an approved stores serial number by the quarantine stores correlating it to hte relevant approved certificate. Whilst in the quarantine store goods are batched to ensure continuity of identity, raw materials are colour identified and temporary protective treatments are repaired or applied as required. A register of incoming goods is kept and when the inspection staff are satisfied that all requirements have been met the goods are passes to the bonded store. Bonded Store The bonded store is the outgoing side of an approved store and as such must be kept separate from the quarantine store. It should contain only aircraft spares and associated equipment that have been proved to conform to specification. The batch numbers of the spares are entered on a record card to maintain Identity and where raw material is issued the identification is retained until last.

MODIFICATIONS It is an alteration to an aircraft, its component units, introduced subsequent to receipt and acceptance by the operator and designed to increase safety, improved performance, meet changes in operating requirements and / or assure positive and substantial economic savings. Modification Embodiment: Classification of Modification: The modifications are classified by the evaluation Committee.

1. MANDATORY: It is time barred - it calls for embodiment within the specified period.

2. ESSENTIAL: As soon as possible after modification parts became available.

3. ON REPACEMENT BASIS: On replacement when

unmodified stocks are utilized/exhausted. All replacement stocks are to be of modified type.

4. OPTIONAL: It may or may not be embodied. It is

optional.

5. DEFERRED: Deferred for a given period of time to obtain further experience. To be re-evaluated.

6. INFORMATION: For record propose only.




TEST FLIGHT

A test flight is required in the following cases;

1. Specific requirements (Refer to concerned MM)

a) Aircraft grounded for more than specific number of

days eg 60 days for B737-300.

b) More than 50 percent power changed. (three

engines out of 4 replaced)

c) Following a Check D.

d) Flight control surfaces replaced.

e) Wings and central section replaced. 2. Major repair subsequent to damage.

3. Performance evaluation. 4. Quality control requirements.

5. CAA requirements.

6. AME requires.

Note: Removal / installation of same component will also be

considered as replacement.

USEFUL INFORMATION QUALITY The quality of a product is the degree to which it meets the requirement of the customer. With manufactured product quality is a combination of quality of design and quality of manufacture. QUALITY CONTROL A management system for programming and coordinating the quality maintenance and improvement efforts of the various group in an Organization, so as to permit the completion of aircraft maintenance in compliance with both CAA requirements and any specific company or customer requirement affecting airworthiness. QUALITY ASSURANCE Overall authority for the supervision of quality standard enabling those standards set by the system of quality control to be enforced. The implementation of the Quality Control requirements should normally be assigned to a Quality Manager who will be responsible for the operation of Quality Assurance tasks utilizing as necessary, a staff of Quality Assurance engineers, who shall be appropriately qualified and experienced, and in sufficient numbers, to properly undertake the work performed by the Quality Department.




AIRCRAFT ON GROUND (AOG) The highest priority designation to process a requirement for a spare part(s) and/or maintenance action. Indicates that an aircraft is unable to continue or be returned to revenue service until the appropriate action is taken. SNAG A known or suspected malfunction, or defect found by flight crew or maintenance personnel which is documented and requires maintenance action. PIREPS (Pilot Reports) Suspected or known malfunctions or unsatisfactory conditions entered by the flight crew into the aircraft log and which require maintenance action. COMPONENT Any self-contained part, combination of parts, sub-assemblies or units which perform a distinctive function necessary to the operation of a system. AIRCRAFT OPERATING CYCLE OR FLIGHT CYCLE A completed take-off and landing sequence. NOTE: Touch and go landings are counted as Aircraft Operating Cycles.

ENGINE OPERATING CYCLE A completed engine thermal cycle including the application of takeoff power. SUPERSONIC CYCLE A completed supersonic flight sequence comprising acceleration through Mach 1 and deceleration to subsonic flight. NOTE: One aircraft operating cycle can include more than one supersonic cycle. DE-RATING The intentional reduction of the stress/strength ratio in the application of an item, usually for the purpose of reducing the occurrence of stress-related failures. DOWNTIME The time during which an aircraft is not available for flight for technical reasons. FLIGHT OR TRIP The entire passage consisting of one or more flight legs, from leaving the airport of origin to arrival at the airport of final destination and operated under one flight number.




EXTRA SECTION (XSEC) Any flight made to accommodate passengers or cargo not handled by the regular flight schedule. CHARTER FLIGHT A revenue flight that is not listed in the published time-table, but is booked for a specified purpose. FERRY FLIGHT A non-revenue flight made to position an aircraft for any reason. FLIGHT SECTOR or FLIGHT LEG Any of the sequential aircraft operating cycles which together constitute a flight. WALK AROUND CHECK A visual check conducted from ground level to detect obvious discrepancies. ITEM Any level of hardware assembly i.e., system, subsystem, module, accessory component, unit, part, etc.) CONSUMABLE ITEM An item that is used only once.

EXPENDABLE ITEM Items for which no authorized repair procedure exists, and for which cost of repair would normally exceed that of replacement. REPAIRABLE ITEM An item comprising or including replaceable parts, commonly economical to repair, and subject to being rehabilitated to a fully serviceable condition over a period less than the life of the flight equipment to which it is related. ROTABLE ITEM An item that can be economically restored to a serviceable condition and, in the normal course of operations, can be repeatedly rehabilitated to a fully serviceable condition over a period approximating the life of the flight equipment to which it is related. LINE REPLACEABLE UNIT A unit which can be readily changed on an aircraft during line maintenance operations. PARTS POOL An arrangement whereby participants are entitled to draw items from the agreed stock held by any participant.




CANNIBALIZATION REMOVAL The removal of an item to satisfy the needs of another aircraft or item. Also called as ROBBERY.

Module 7 (Maintenance Practices) Sub Module 7.20 (Maintenance Procedures).pdf

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