CHAPTER 3. PROGRAM AIMINISTRATION
25. GENERAL• Administration of reliability programs (as discussed in this circular) requires a specific organizational structure within the operator's maintenance organization. Participants should be drawn from appropriate elements of the organization and should be authorized to act on behalf of their elements. The highest maintenance official or his designee should participate in the administration of the program. He should serve as the final authority for major activities and for program changes requiring FAA approval.
b. The makeup of the administration group may vary considerably from one operator to another. It may have a technical board that analyzes performance deteriorations and shop findings to make determinations that may be acted on by an administrative board. The two boards can be combined if this better serves the needs of the particular operator. The board type of administration should entail meetings scheduled for some specified interval and should
c. In lieu of a formal board, operators with sufficient organizational capability which should include a strong engineering function may administer their program by assigning appropriate responsibilities to each organizational element. In this type arrangement, responsibility for operation of the program should be assigned to a specific element of the operator's organization.
Procedures for operating each of the systems described in chapter 2 of this publication are essential to the success of the program. These procedures should be incorporated in appropriate sections of the operator's manual system. This will provide each organizational element, and individuals therein, instructions as to their part in the program. Forms should be used, as necessary, to facilitate and document recurring transactions that involve several elements such as (1) changes from one maintenance process to another,
(2) analysis of substandard system or component mechanical performance, (3) shop disassembly analysis for condition-monitoring purposes or overhau frequency adjustment, etc., and (4) sampling inspection for aircraft check or inspection adjustment.
26. RELIABILITY PROGRAM DOCUMENT. The operator should develop a document describing the application of reliability control methods.
a. This document should include at least the following:
(1) General description of the program.
(2) Organizational structure, duties and responsibilities.
(3) Description of the individual systems.
Chap 3 Par 25 Page 25
(4) Derivation of performance standards (if used).
(5) Changes to the program including designation of changes requiring FAA approval.
(6) Copy and explanation of all forms peculiar to the system.
(7) Revision control and certification of revisions to the document.
b. The document should describe the workings of all systems in sufficient detail to provide for proper operation of the program. It should include in detail how the three maintenance processes are applied. The document should describe the monthly report and any other reports relative to the program, and include samples of these reports with instructions for their use.
organizational element (s) responsible for publishing reports should be identified and the distribution should be stated. Copies of pertinent reports should be provided to FAA.
C. The document should also include definitions of significant terms used in the program with particular emphasis on definitions of the three maintenance processes.
27.-34. RESERVED.
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Page 26 (thru 34) Par 26
CHAPTER 4. PROGRAM APPROVAL INITIAL APPROVAL. FAA Form 1014, Operations Specifications, (OMB 04-R0075) is used for initial approval of reliability programs. This form, along with the program document and related data should be submitted to the FAA district office assigned responsibility for that operator.
Guidance on the preparation of FAA Form 1014 is available from the FAA district office. Approval will be certified in the program docunent in addition to the operations specifications.
36. REVISION APPROVAL. Revisions requiring formal approval (ref: chapter 2, paragraph 15.g. of this circular) will be subject to the same consideration as initial approval. The mechanics of the approval certification will be as defined in the document. If the revision concerns items listed in the operations specifications, the effected page(s) will be amended to reflect the revision.
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Appendix 1 AIRLINE/MANUFACTURER MAINTENANCE PROGRAM PLANNING DOCUMENT - MSG-2 (Prepared by: R & M Subcommittee, Air Transport Association) (Date: March 25, 1970)
1.O GENERAL Introduction. Airline and manufacturer experience in developing scheduled maintenance programs for new aircraft has shown that more efficient programs can be developed through the use of logical decision processes. In July, 1968 representatives oi various airlines developed Handbook #MSG-1, "Maintenance Evaluation and Program Development,' which included decision logic and interairline/manufacturer procedures for developing a maintenance decided that experience gained on this project should be applied to update the decision logic and to delete certain 747 detail procedural information so that a universal document could be made applicable for later new type aircraft. This has been done and has resulted in this document, #MSG-2.
Objective. It is the objective of this document to present a means for developing a maintenance program which will be acceptable to the Regulatory Authorities, the Operators, and the Manufacturers.
The maintenance program data will be developed by coordination with specialists from the operators, manufacturers, and when feasible, the regulatory authority of the country of manufacture.
Specifically it is the objective of this document to outline the general organization and decision processes for determining the essential scheduled maintenance requirements for new airplanes.
Historically, the initial scheduled maintenance program has been specified in Maintenance Review Board Documents. This document is intended to facilitate the development of initial scheduled maintenance programs. The remaining maintenance, that is nonscheduled or nonroutine maintenance, is directed by the findings of the scheduled maintenance program and the normal operation of the aircraft. The remaining maintenance consists of maintenance actions to correct discrepancies noted during scheduled maintenance tasks, nonscheduled maintenance, normal operation, or condition monitoring.
1•3 Scope. The scope of this document shall encompass the maintenance program for the entire airplane.
1•4 Organization. The organization to carry out the maintenance program development pertinent to a specific type aircraft shall be staffed by representatives of the Airline Operators purchasing the equipment, the Prime Manufacturers of the airframe and powerplant and when feasible the Regulatory Authority.
Appendix l 10401 The management of the maintenance program development activities shall be accomplished by a Steering Group composed of members from a representative number of Operators and a representative of the Prime Airframe and Engine Manufacturers. It shall be the responsibility of this group to establish policy, direct the activities of Working Groups or other working activity, carry out liaison with the manufacturer and other operators, prepare the final program recommendations and represent the operators in contacts with the Regulatory Authority.
1.4.2 A number of Working Groups, consisting of specialist representatives from the participating Operators, the Prime Manufacturer, and when feasible the Regulatory Authority, may be constituted. The Steering Group, alternatively, may arrange some other means for obtaining the detailed technical information necessary to develop recommendations for maintenance programs in each area. Irrespective of the organization of the working activity, it must provide written technical data that support its recommendations to the Steering Group. After approval by the Steering Group, these analyses and recommendations shall be consolidated into a final report for presentation to the Regulatory Authority.
200 DEVELOPMENT OF MAINTENANCE PROGRAMS 201 Program Requirement. It is necessary to develop a maintenance program for each new type of airplane prior to its introduction into airline service.
20101 The primary purpose of this document is to develop a proposal to assist the Regulatory Authority to establish an initial maintenance program for new types of airplanes.
The purpose of this program is to maintain the inherent design ievels of operating safety.* This program becomes the basis for the first issue of each airline's Operations Specifications-Maintenance to govern its initial maintenance policy. These are subject, upon application by individual airlines, to revisions which may be unique to those airlines as operating experience is accumulated.
2.1.2 It is desirable, therefore, to define in some detail:
(a) The objectives of an efficient maintenance program,
(b) The content of an efficient maintenance program, and
(c) The process by which an efficient maintenance program can be developed.
* See Glossary.
Appendix 1 20103 The Objectives of an efficient airline maintenance program are:
(a) To prevent deterioration of the inherent design levels of reliability and operating safety of the aircraft, (Б) To accomplish this protection at the minimum practical costs.
These objectives recognize that maintenance programs, as such, cannot correct deficiencies in the inherent design levels of flight equipment reliability. The maintenance program can only prevent deterioration of such inherent levels. If the inherent levels are found to be unsatisfactory, engineering action is necessary to obtain improvement.
2.1.5 The maintenance program itself consists of two types of tasks:
(a) 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, and
(b) A group of nonscheduled tasks which results from:
(i) The scheduled tasks accomplished at specified intervals,
(ii) Reports of malfunctions (usually originated by the flight crew), or
(iii) Condition Monitoring.
The objective of these nonscheduled tasks is to restore the equipment to its inherent level of reliability.
This document describes procedures for developing the scheduled maintenance program. Nonscheduled maintenance results from scheduled tasks, normal operation or condition monitoring.
2.1.6 Maintenance programs generally include one or more of the following primary maintenance processes:
Hard Time Limit: A maximum interval for performing maintenance tasks. These intervals usually apply to overhaul, but also apply to total life of parts or units.
Appendix 1 On Condition: Repetitive inspections, or tests to determine the condition of units or systems or portions of structure (Ref.: FAA Advisory Circular 121-1).
Conditior Monitoring: 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 analysis of unit performance.
No specific monitoring system is implied for any given unit (Ref.: FAA Procedures 8310.4, paragraph 3033).
This document results in scheduled tasks that fit the hard time limit or on condition maintenance programs or, where no tasks are specified, the item is included in condition monitoring.
2.2 Scheduled Maintenance Program Content The tasks in a scheduled maintenance program may include:
(a) Servicing
(b) Inspection
(c) Testing
(a) Calibration
(e) Replacement
2.2.1 An efficient program is one which schedules only those tasks necessary to meet the stated objectives. It does not schedule additional tasks which will increase maintenance costs without a corresponding increase in reliability protection.
2.2.2 The development of a scheduled maintenance program requires a very large number of decisions pertaining to:
(a) Which individual tasks are necessary,
(b) How frequently these tasks should be scheduled,
(c) What facilities are required to enable these tasks to be accomplished, Page 4
Appendix 1
(d) Where these facilities should be located, and
(e) Which tasks should be accomplished concurrently in the interests of economy.
2•3 Aircraft System Component Analysis Method. The method for determining the content of the scheduled maintenance program for systems and components (parts a and b of Paragraph 2.2.2) uses decision diagrams. These diagrams are the basis of an evaluatory process applied to each system and its significant items using technical data provided (Ref. 2.7). Principally, the evaluations are based on the systems' and items' functions and failure modes.
The purpose is to:
(a) Identify the systems and their significant items*.
(b) Identify their functions*, failure modes*, and failure reliability*.
(c) Define scheduled maintenance tasks having potential effectiveness* relative to the control of operational reliability*.
(d) Assess the desirability of scheduling those tasks having potential effectiveness.
It should be noted that there is a difference between "Potential" effectiveness of a task versus the "desirability" of including this task in the scheduled maintenance program.
The approach taken in the following procedure is to plot a path whereby a final judgment can be made as to whether those potentially effective tasks are worthy of inclusion in an initial maintenance program for a new airplane.
There are three decision diagrams provided (Addendum I, Figures 1 through 3). Figure 1 is used to determine scheduled maintenance tasks having potential effectiveness relative to the control of operational reliability. This determines tasks which can be done.
Figures 2 and 3 are used to assess the desirability of scheduling those tasks having potential effectiveness.
Figure 2 tasks must be done to prevent direct adverse effects on operating safety and to assure availability of hidden functions.
Figure 3 tasks should be done for economic value.
* See Glossary.
Appendix l
2.3.3 The total analysis process is shown diagramatically below.
See Addendum I for details.
Figure 1 Figure 2 Figure 3 (Questions a,b,c,d, e) (Questions I & II) (Questions A, B & C) Flight Crew Tasks a · Tasks N Tasks T c DA B C Tasks d (Eval) S Tasks e These tasks have These tasks must These tasks should potential effec- be done to prevent be done for economic tiveness & can direct adverse value.
be done. effects on operating safety & assure availability of hidden functions.
20304 The following guidelines encourage consideration of failure consequences and the potential effectiveness of scheduled maintenance tasks. In those cases where failure consequences are purely economic, the guidelines lead to consideration of both the cost of the scheduled maintenance and the value of the benefits which will result from the task.
Appendix 1 20305 A decision tree diagram (Figure 1 of Addendum 1) facilitates the definition of scheduled maintenance tasks having potential effectiveness. There are five key questions.
Note: Questions (a), (b), and (c) must be answered for each failure mode, question (d) for each function, and question (e) for the item as a whole.
(a) Is reduction in failure resistance* detectable by routine flight crew monitoring*?
(b) Is reduction in failure resistance detectable by in situ maintenance or unit test?
(c) Does failure mode have a direct adverse effect upon operating safety? (See Addendum 2.)
(a) Is the function hidden from the viewpoint of the flight crew? (See Addendum 3.)
(e) Is there an adverse relationship between age and reliability?
2.306 Each question should be answered in isolation, e.g., in question (c) all tasks which prevent direct adverse effects on operating safety must be listed. This may result in the same task being listed for more than one question.
If the answer to question (a) is Yes, this means there are methods available through monitoring of the normal in-flight instrumentation to detect incipient conditions before undesirable system effects occur. A Yes answer does not require a maintenance task. If the answer is No, there is no in-flight monitoring which can detect reduction in failure resistance. This question is meant to refer to the flight crews' ability to detect deteriorating calibration or systems operation before a failure occurs. NOTE: Tasks resulting from in-flight monitoring are part of nonscheduled
2.3.8 If the answer to question (b) is Yes, it means there is a maintenance task, not requiring item disassembly, that has potential effectiveness in detecting incipient conditions* before undesirable system effects occur. Tasks may include inspection, servicing, testing, etc. NOIE: Tasks resulting from a les answer to question (b) are part of the On Condition maintenance program.
* See Glossary.
Appendix l If the answer to question (c) is Yes, this failure mode has a direct, adverse effect on operating safety. It is necessary to examine the mechanism of failure and identify the single cells or simple assemblies where the failure initiates. Specific total time, total might cycle, time since overhaul and cycle since overhaul limitations may be assigned these single cells or simple assemblies and the.
probability of operational failures will be minimized.
Examples of these actions are turbine engine disc limits, airplane flap link life limits, etc. In many cases, these Limits must be based upon marufacturer's development testing.
Fortunately, there is only a small number of failure modes which have a direct, adverse effect on operating safety.
This results from the fact that failure mode analyses are conducted throughout the process of flight equipment design.
In most cases, it is possible after identification of such a failure mode to make design changes (redundancy, incorporation of protective devices, etc.) which eliminate its direct adverse effect upon operating safety. If no potentially effective task exists, then the deficiency in design must be referred back to the manufacturer. The term "direct adverse effect upon operating safety" is explained in Addendum 2. NOTE: Tasks resulting from a Yes answer to question (c) are part of either the Hard Time limitation maintenance program or the On Condition maintenance program.
Refer to Addendum 3 for explanation of question (d). If the answer to question (d) is Yes, periodic ground test or shop tests may be required if there is no other way of ensuring that there is a high probability of the hidden function being available when required. The frequencies of these tests are associated with failure consequences and anticipated failure probability. A component cannot be considered to have a hidden function if failure of that function results in a system malfunction which is evident to the flight crew during normal operations. In this case, the answer must be No. NOTE: Tasks resulting from a Yes answer to question (d) may be part of either the Hard Time limitation or the On-Condition maintenance program.
2.3.11 If the answer to question (e) is Yes, periodic overhaul may be an effective way of controlling reliability. Whether or not a fixed overhaul time limit will indeed be effective can be determined only by actuarial analysis of operating experience. NOI: Tasks resulting from a Yes answer to question (e) are part of the Hard Time limitation mainte nance program.
Appendix 1
2.3012 It has been found that overall measures of reliability of complex components, such as the premature removal rate, usually are not functions of the age of these components.
in most cases, thereiore, the answer to question (e) is No. In this event, scheduled overhaul cannot improve operating reliability. Engineering action is the only means of improving reliability. These components should be operated, therefore, without scheduled overhaul. NoIE:
Systems or items which require no scheduled tasks are included in Condition Monitoring.
The preceding paragraph is contrary to the common belief that each component has an unique requirement for scheduled maintenance in order to protect its inherent level of reliability. The validity of this belief was first challenged by actuarial analyses of the life histories of parting pograph has ee enth the ely detonate at the by the massive operational experience of many airlines with many different types of components covered by Reliability Programs complying with FAA Advisory Circular 120-17.
It is possible to change the answers to the five questions in the decision diagram by improved technology. it is hoped that Aircraft Integrated Data Systems (AIDS), for example, will reliably indicate reduced resistance to various modes of failure of many components during normal airline operations. If this is determined to be possible, many "No" answers to questions (a) and (b) will become "Yes" answers. Answers may also be changed by various developments in the field of nondestructive test techniques, built-in test equipment, etc.
The questions in Figure l are intended to determine maintenance tasks having potential effectiveness for possible inclusion in a scheduled maintenance program. However, it is probable that many of these "potentially" beneficial scheduled tasks would not be "desirable" even though such tasks could improve reliability. This might be true when operating safety is not affected by failure or the cost of the scheduled maintenance task is greater than the value of such resulting benefits as reduced incidence of component premature removal, reduced incidence of departure delays, etc. Additional diagrams are used to assess the "desirability" of those scheduled maintenance actions which have potential effectiveness. This is accomplished by Figures 2 and 3 of Addendum 1.