Aircraft Maintenance 12422_03

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Chapter Three Regulations A 11 of the functions in aircraft operations and maintenance are fully regulated. Individual nations develop their own regulatory require- ments for the companies operating within their respective nations. These requirements are all within the international regulatory require- ments agreed to by most nations where aircraft operations are carried out under the aegis of the International Civil Aviation Organization (ICAO). For the United States, these regulations are codified by the Federal Avia- tion Administration (FAA) and are contained in the Federal Aviation Regulations (FAR). The regulations prescribe rules governing the maintenance, preventive maintenance, rebuilding, and alteration of any of the following: (1) air- craft having a U.S. airworthiness certificate, and (2) airframe, aircraft engines, propellers, appliances, and component parts of such aircraft. The rules also prescribe the manner in which these activities will be carried out, as well as the processes and the manner in which all activities will be recorded and approved. Specifically the certificate holder is responsible for the following: (1) the air- worthiness of its aircraft, including airframes, aircraft engines, propellers, appliances, and parts thereof, and (2) the performance of the maintenance, preventive maintenance, and alteration of its aircraft, in accordance with its manuals and the regulations of FAR Parts 121.361 to 121.369. These sections require that each certificate holder must have an organization adequate to perform the work and must organize the functions to separate the required inspection functions from the other maintenance, preventive maintenance, and alterations functions. Separation must be below the level of administra- tive control at which the overall responsibility for the required inspection functions and other maintenance, preventive maintenance, and alteration functions are exercised. 21

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Transcript of Aircraft Maintenance 12422_03

Page 1: Aircraft Maintenance 12422_03

Chapter Three

Regulations

A 11 of the functions in aircraft operations and maintenance are fully regulated. Individual nations develop their own regulatory require- ments for the companies operating within their respective nations.

These requirements are all within the international regulatory require- ments agreed to by most nations where aircraft operations are carried out under the aegis of the International Civil Aviation Organization (ICAO). For the United States, these regulations are codified by the Federal Avia- tion Administration (FAA) and are contained in the Federal Aviation Regulations (FAR).

The regulations prescribe rules governing the maintenance, preventive maintenance, rebuilding, and alteration of any of the following: (1) air- craft having a U.S. airworthiness certificate, and (2) airframe, aircraft engines, propellers, appliances, and component parts of such aircraft. The rules also prescribe the manner in which these activities will be carried out, as well as the processes and the manner in which all activities will be recorded and approved.

Specifically the certificate holder is responsible for the following: (1) the air- worthiness of its aircraft, including airframes, aircraft engines, propellers, appliances, and parts thereof, and (2) the performance of the maintenance, preventive maintenance, and alteration of its aircraft, in accordance with its manuals and the regulations of FAR Parts 121.361 to 121.369. These sections require that each certificate holder must have an organization adequate to perform the work and must organize the functions to separate the required inspection functions from the other maintenance, preventive maintenance, and alterations functions. Separation must be below the level of administra- tive control at which the overall responsibility for the required inspection functions and other maintenance, preventive maintenance, and alteration functions are exercised.

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The certificate holder also must ensure that all work is performed by compe- tent personnel in accordance with the certificate holder’s manual and have adequate facilities and equipment.

Maintenance Program Requirements

With the advent of jet transport category aircraft, it was necessary to establish reliability maintenance programs adjusted to the requirements of large, tech- nically advanced airplanes incorporating complex interrelated systems. This requirement had been recognized with the advent of the Douglas DC-8 and the Boeing 707-type aircraft. The advent of the k i n g 747 in the 1960s pre- cipitated the industry to initiate a new approach to continuous maintenance based on decision tree analysis. The analysis was used to define the follow- ing in some detail:

The objectives of an efficient maintenance program

The content of an efficient maintenance program

The process by which an efficient maintenance program can be developed

The objectives of an efficient airline maintenance program are as follows:

To prevent the deterioration of the inherent design levels of reliability and operating safety of the aircraft

To accomplish this protection at the minimum practical cost

The maintenance program itself consists of two types of tasks:

1. A group of scheduled tasks to be accomplished at specified intervals. The objective of these tasks is to prevent deterioration of the inherent design levels of aircraft reliability.

2. A group of nonscheduled tasks that result from any of the following:

The scheduled tasks accomplished at specific intervals

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Reports of malfunctions (usually originated by the flight crew) Condition monitoring

The objective of these nonscheduled tasks is to restore the equipment to its inherent level of reliability.

Maintenance programs generally include one or more of the following to determine the appropriate maintenance action:

Hard-time limit. This is the maximum interval for performing maintenance tasks. This interval usually applies to overhaul, but also applies to the total life of parts or units.

On condition. These are repetitive inspections or tests to determine the condition of units or systems or portions of the structure.

Condition monitoring. This is for items that have neither hard-time limits nor on-condition maintenance as their primary maintenance process. Condition monitoring is accomplished by appropriate means available to an operator for finding and resolving problem areas. These means range from notices of unusual problems to special analyses of unit performance.

Scheduled Maintenance Programs The tasks in a scheduled maintenance program may include servicing, inspec- tion, testing, calibration, and replacement. An efficient program is one that schedules only those tasks necessary to meet the stated objectives. It does not schedule additional tasks that will increase maintenance costs without a cor- responding increase in reliability protection.

The method for determining the content of the scheduled maintenance pro- gram for systems and components uses decision tree diagrams. These dia- grams are the basis of an evaluation process applied to each system and its sigruficant items, using technical data provided by the manufacturers. Princi- pally the evaluations are based on the systems’ and items’ functions and fail- ure modes.

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E N G I N E E R I N G

Three decision tree diagrams are utilized. The first is used to determine scheduled maintenance tasks having potential effectiveness relative to the control of operational reliability. This determines tasks that can be done.

The second and third diagrams are used to assess the desirability of schedul- ing those tasks having potential effectiveness. The second diagram defines tasks that must be done to prevent direct adverse effects on operating safety and to ensure detection of hidden functions. The third diagrams are tasks that should be done for economic value. Each of the elements of the airplane (e.g., structure, powerplant, components) is analyzed individually utilizing the decision tree diagrams (Figure 5).

The original document was developed from a proposal to the Boeing Com- pany in1966/1967 by carriers (Industry Steering Committee) that had B747 aircraft on order (Pan American Airlines, American Airlines, United Airlines, Trans-World Airlines, British Overseas Airways, and Air Canada). This Indus- try Steering Committee rapidly expanded to more than 160 airline representa- tives divided into task groups to analyze the maintenance requirements for all of the B747 aircraft structure, components, and systems. The FAA partici- pated in these task groups. The completed document was then provided to the FAA as MSG-1 (Maintenance Steering Guide). The document is in the custody of the ATA. It was used by the Maintenance Review Board (MRB) to develop the B747 maintenance program.

The MRB is the regulatory group by which the FAA develops the minimum required maintenance requirements for a specific type of aircraft, in compli- ance with applicable FAA regulations. The manufacturer then converts the MRB document to its maintenance planning document (MPD/OAMP [on aircraft maintenance program]), which the airlines then use to establish their own programs, including the development of task cards and other documents for the actual work accomplishments.

Each maintenance organization utilizes the MSG and MRB documents spe- cific for its type aircraft to establish its initial aircraft maintenance program for submission to the regulatory authority. When the authority has approved the document, the maintenance organization, based on subsequent operating experience and requirements, initiates amendments to serve its needs. Until it successfully puts into position a satisfactory reporting and continuous

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Tasks That Can Be Done Tasks That &g Be Done Tasks That Should Be Done

Is reduction in failure resistance detectable by

Is reduction in fallure resistance

test?

Does failure mode have a direct adverse effect on operating safety?

hidden frcnn the viewpoint of the

Is there an adverse relationship between age and reliability?

Means of in-flight monitoring

List all potentla1 tasks ref. to reduct. in failure resist. (check, Inspect, service)

Is elapsed time for correction of failure > 0.5 hour?

Disposition of task relative to program

Figure 5. Maintenance program development utilizes a decision tree process to assess the potential effect of failure and -.-L-Ll:.-L - 1----1 LA- --AL:f:--A:.--

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reliability assessment program, a maintainer must apply to the regulatory authority for changes to the maintenance program.

To maintain the credibility of the maintenance and reliability programs, the cer- tificate holder must establish and maintain a system for the continuing analysis and surveillance of the performance and effectiveness of its inspection program and the program covering other maintenance, preventive maintenance, and alterations, and for the correction of any deficiencies in those programs, regard- less of whether those programs are carried out by the certificate holder or by another person. All maintenance organizations are required to have a reliabil- ity analysis report document. This document must include the following:

Pilot reports

Maintenance technical fleet monitoring 24/7

Daily review and analysis of technical performance

Quality review of component reliability

Ongoing analysis of discrepancies found during service and walk- around checks

Ongoing analysis of discrepancies found during ”A,” “C,” “K,” and supplementary structure inspection (SSI) checks

Discussions with the manufacturer’s in-house product support representatives with regard to industry technical issues

Continuous surveillance and monitoring by in-house FAA inspectors

Labor and material usage

Unscheduled (U/S) removals per 1,000 hours

Check worksheets

Technical worksheets

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The methods by which a maintenance organization may alter the existing initially approved maintenance program must be in accordance with FAA Advisory Circular 120-17A and FAA Order 8300.10, which calls for a reli- ability analysis program (RAP). The program document must include data collection systems, data analysis programs, and revision capability for per- formance standards, corrective action programs, interval adjustment, and process change.

Continuous Airworthiness The development and approval of maintenance programs is only one element of the mandate of the FAA to ensure the continuous airworthiness of aircraft. The requirements for the preparation of instructions for continued airworthi- ness as required by FAR Section 25.1529 are contained in Appendix H of FAR Part 25. The instructions must include information for each engine and each component, and any required information relating to the interface of those components and units with the airplane. The maintainer must also send the FAA its program to show how changes to the instructions for continued airworthiness for units and components installed in the airplane will be com- municated. The instructions must be in the form of a manual or manuals.

Additional Regulatory Requirements In addition to these requirements, the certificate holders are required to abide by other FAA requirements.

Part 3 9 Airworthiness Directives. Airworthiness directives are the means by which the FAA requires changes in the form of modifications to the air- craft, alterations to the operations manuals, or any change that in its opinion is required to ensure the ongoing safety of the aircraft after it has been put into service. Generally, an airworthiness directive is issued only following the issuance of a notice of proposed rule making (NPRM) to allow comments from the industry with regard to the requirements in the proposed airworthi- ness directive. In critical circumstances, the FAA may issue an emergency air- worthiness directive to take effect either immediately or within a very close time frame, to prevent a failure that may be catastrophic.

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E N G I N E E R I N G

Part 43: Maintenance, Preventive Maintenance, Rebuilding, and Alteration. This part prescribes the rules governing the maintenance, preven- tive maintenance, rebuilding, and alteration of any of the following: (a) air- craft having a U.S. airworthiness certificate, (b) foreign-registered aircraft used in common carriage under the provisions of FAR Part 121 or 135, (c) air- frames, aircraft engines, propellers, appliances, and components of such air- craft, (d) all life-limited parts that are removed from a type certificated product, segregated or controlled as provided in this section. It further covers the requirements for the following:

1.

2.

3.

4.

5.

6.

7.

8.

9.

The records of overhaul and rebuilding

The persons authorized to perform maintenance, preventive mainte nance, rebuilding, and alterations

Approval for return to service after maintenance, or preventive maintenance, rebuilding, and alterations

Persons authorized to approve aircraft, airframes, aircraft engines, propellers, appliances, or component parts for return to service after maintenance, preventive maintenance, rebuilding, or alteration

Content, form, and disposition of maintenance and other records (e.g., a description of the work performed, the date of completion of the work, the name of the persons performing the work, the signature and certificate number and kind of certificate held by the persons approving the work)

Disposition of life-limited parts

Content, form, and disposition of records for inspection conducted under Parts 91,125, and 135

Maintenance records: falsification, reproduction, or alteration

Performance rules

10. Airworthiness limitations

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Part 121: Certification and Operations: Domestic, Flag, Supplemental Air Carriers, and Commercial Operators of Large Aircraft. Specifically with reference to this book, Part 121 Subpart L covers the requirements for mainte- nance, preventive maintenance, and alterations. This section is substantiation for the sections on maintenance programs, maintenance organizations and structures, maintenance systems, continuous analysis and surveillance, and maintenance recording requirements.

This section covers all of the operating requirements for the referenced carri- ers. It includes applicability., approval of routes, manual requirements, air- craft requirements (e.g., aircraft proving tests, aircraft certification and equipment requirements), airplane performance operating limitations (e.g., weight, takeoff, en route, two-engine inoperative en-route limitations for air- planes with four or more engines), special airworthiness requirements (e.g., cabin interiors, ventilation, fire precautions, location of fuel tanks, firewalls, fire extinguishing systems, fire detector systems, carriage of cargo in passen- ger compartments, landing gear [oral warning device], demonstration of emergency evacuation procedures), and instrument and equipment require- ments (e.g., flight and navigational equipment, portable electronic devices, engine instruments, emergency equipment, seats, safety belts, and shoulder harnesses, cockpit check procedures, supplemental oxygen for sustenance, radio equipment, traffic alert and collision avoidance system, airborne weather radar equipment, cockpit voice recorders).

From the standpoint of operators with large transport airplanes, this part of the FAR is the most important with which to be familiar and to understand its legal requirements. Other nations have similar legislation by which their car- riers must abide.

The FAA also issues Handbook of Airworthiness Bulletins (HBAW). These bulletins are provided to assist FAA inspectors and operators in carrying out their responsibilities according to the previously described regulations. The FAA Order 8300.10 is the airworthiness inspector’s handbook. Chapters in this handbook define how the FAA will accomplish its mandated responsibilities.

Chapter 61 of Volume 2 describes the process used to evaluate an applicant for Part 121 or Part 135 certificates. It establishes the phases for the applica- tion, such as the Pre-Application Statement of Intent (PASI), and the meetings

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and documents (e.g., management resumes, the aircraft, the station facilities and services, the communication facilities and services, the maintenance facilities and services, the aeronautical charts and related publications, the contract training or facilities), and the formal application phase of (1) the logic of the sequence of events for the application, (2) the timeliness of the events (the schedule of events must be reasonable, realistic, and provide sufficient time for the FAA certification team to review the various documents, manu- als, and proposals), and (3) completeness of events. The FAA also must ensure that the applicants clearly understand their commitments.

Chapter 64 of Volume 2 provides guidance for evaluating a continuous air- worthiness maintenance program developed by the operator/applicant in accordance with Title 14 of CFR Part 121 or 135. The regulations specify that each operator/applicant must have a maintenance program adequate to per- form the work, and a separate inspection program adequate to perform the required inspections. A continuous airworthiness maintenance program com- bines the maintenance and inspection functions used to fulfill the total main- tenance needs of the operator/applicant.

The basic requirements of a continuous airworthiness maintenance program include the following:

1. Inspection 2. Scheduled maintenance 3. Unscheduled maintenance 4. Overhaul and repair 5. Structural inspection 6. Required inspection items (RII) 7. Reliability program

Chapter 66 of Volume 2 provides guidance for approving an operator’s reli- ability program. It establishes the time limitations or standards for determin- ing intervals between overhauls, inspections, and checks of airframes, engines, propellers, appliances, and emergency equipment. It is based on the primary maintenance process defined in MSG-2, including definitions for hard time, on condition, and condition monitoring.

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Inspections and Audits

The regulatory authorities in all nations are mandated to carry out any and all inspections to ensure absolute compliance with all regulatory legal require- ments and operational orders. In the United States, this function is carried out by the FAA, which utilizes many procedures to accomplish its mandate. It also has the legal authority to enact civil penalties for infractions, enforce cease and desist orders, and such other procedures as may be required to ensure the safety of aircraft. Many of these processes and procedures are out- lined in the FAA compliance and enforcement handbook.

Within the last several years, partly as a result of the growth in aviation and the resources required to carry out its mandate, the FAA has been altering its inspection and audit procedures to include dynamic ongoing oversight sys- tems such as the air transportation oversight system (ATOS). This program, with the carrier’s continuous analysis and surveillance system (CASS), the MRB activities, and the maintenance procedures carried out as required by MSG-l/2/3, constitutes continuous oversight. The system allows the FAA at any time to institute a system analysis team (SAT) to inspect and audit either the carrier operations in their entirety or some specific elements with which the FAA may be concerned.

Materials

It is of extreme importance to recognize that the regulatory authority of the country of manufacture must certificate each and every part that is on or installed in an aircraft. These are the parts that are designed by the original manufacturer and approved by the regulatory agency for installation. No part may be installed which is not an approved part by the regulatory agency. The FAA Airworthiness Handbook Bulletin 97-10 identifies a program track- ing and reporting subsystem (PTRS) . As a result of an increasing number of unapproved parts that do not meet design criteria coming into the supply chain, it is mandatory for all aircraft maintainers and operators to report sus- pected unapproved parts (SUP) to the regulators.

In the event that a carrier wishes to manufacture detailed parts or have detailed parts manufactured on its behalf, it must obtain a parts manufacturer approval (PMA) from the regulator to do so.

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E N G I N E E R I N G

Should a carrier wish to make a modification to a system, component, or part of an aircraft, which will affect the design, operation, or mission of the aircraft, it must obtain a supplemental type certificate from the regulatory authority and certify that changes do not affect the regulatory requirements for safety of flight or airworthiness of aircraft (e.g., aircraft cargo conversions, noise sup pressor installations, in-flight entertainment systems).

In summary, from the time the design of an aircraft is conceived, the design must be in accordance with the many regulatory design requirements. The aircraft must be produced in accordance with a specification that has been approved by the FAA. All materials for the aircraft must meet a specification established to ensure their capability of meeting the design purpose and requirements. Once in service, the aircraft is required to be operated and maintained within a very specific set of legal requirements. In addition, con- tinuous monitoring, as defined by specific regulatory documents, permits the FAA to inspect for compliance and to penalize noncompliance at any time. All of the activities-from the initiation of aircraft design to its retire- ment-are carried out by organizations and personnel approved by the regu- latory authorities.

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