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4-3. REQUIRED AIR CARRIER MAINTENANCE ORGANIZATIONAL STRUCTURE.
a. Structure. We wrote the regulations defining an air carrier maintenance organization necessarily broad given the different types and sizes of air carriers. A single means of compliance or a single organizational chart that would apply to all the different types and sizes of air carrier organizations is not possible.
b. Accountable Manager. You should designate an individual or position as the accountable manager with the authority and the overall responsibility for managing and implementing your entire maintenance program, including all inspection functions. The individual you designate must meet the qualifications for the Director of Maintenance listed in § 119.67(c) or § 119.71(e), as applicable. The inspection functions and the required inspection functions are part of your maintenance program.
c. Organizational Functions. The FAA recommends your maintenance organization have three general organizational functions to ensure that you conduct all operations to the highest possible degree of safety. If you are a larger organization, you may have different departments for each level, while in the smallest organizations, you may carry out these functions through one or two individuals, maybe as a collateral duty. Generally, these three organizational functional levels include:
(1) Mechanics and/or inspectors performing the work at the first level (operations);
(2) Middle managers and supervisors at the second level (tactics); and
(3) The maintenance program accountable manager at the third level (strategy).
d. Authority and Responsibility. We expect you to assign clear authority and responsibility in your maintenance organization, including delegated responsibility, for the overall maintenance program and all of its elements and functions. You should include a position description that includes each position’s duties and responsibilities in your manual so that there is not a fragmented organizational system with a high risk for confusion over who is responsible for a given element, process, or task. Watch out for hidden duties and responsibilities where the duty and/or responsibility is shown in a process but not in the position description.
4-4. SEPARATION OF INSPECTION AND MAINTENANCE DEPARTMENTS.
a. Regulatory Requirements.
(1) If you perform maintenance (other than required inspections), §§ 121.365(a) and 135.423(a) require you to have an organization that is adequate to perform maintenance work. Additionally, if you perform required inspections, §§ 121.365(b) and 135.423(b) require you to have an organization that is adequate to perform required inspection work.
Par 4-4 Page 13
(2) Don’t confuse your maintenance production department with your maintenance organization. Also, don’t confuse your inspection department, if you have one, with your required inspection organization. We have defined “maintenance” in § 1.1 as “inspection, overhaul, repair, preservation, and the replacement of parts, but excluding preventive maintenance.” We do not define required inspection in § 1.1. However, within the context of parts 121 and 135, the term “required inspection” has a very specific regulatory meaning and should not be confused with the general use of the word “inspection” throughout the regulations.
(3) While there is no regulatory requirement to separate the maintenance organization from the required inspection organization, there is a requirement when performing both maintenance and required inspection work to organize the performance of those functions so as to separate the maintenance function from the required inspection function.
b. Organization. Regulations require you to organize the performance of all maintenance functions, including inspection, repair, overhaul, and the replacement of parts, to separate the function of required inspections from the function of the other maintenance, preventive maintenance, and alteration activities. This organizational separation must be below the level of administrative control where you exercise overall responsibility for the required inspection functions as well as the other maintenance, preventive maintenance, and alteration functions.
Consistent with subparagraph 4-3b, your accountable manager exercises overall authority and responsibility over the required inspection functions, as well as the other maintenance (including inspection), preventive maintenance, and alteration functions. Refer to Figure 4-1, Maintenance Organizational Chart, for a representative organizational chart.
FIGURE 4-1. MAINTENANCE ORGANIZATIONAL CHART Maintenance Organization Accountable Manager Overall authority and responsibility for both RII and other maintenance and alteration functions Maintenance Department Responsible Manager Direct responsibility for maintenance, preventive maintenance and alteration functions Required Inspection Organization Responsible Manager Direct responsibility for RI functions Mechanic RII Inspectors Page 14 Par 4-4
Par 5-1 Page 15 CHAPTER 5. ACCOMPLISHMENT AND APPROVAL OF MAINTENANCE AND
ALTERATIONS
5-1. ACCOMPLISHMENT OF MAINTENANCE.
a. Authority To Perform Maintenance. As a maintenance entity, you have authorization under §§ 43.3(f), 43.7(e), 121.379, and 135.437 to perform maintenance on your own air carrier aircraft and to approve them for RTS without obtaining any other maintenance certification. In addition, §§ 121.379 and 135.437 provide clear authority for you, under your air carrier certificate, to perform maintenance on behalf of other air carriers who conduct operations under the same part as you do.
b. Certificate Requirements.
(1) Each individual who makes an airworthiness determination on your behalf must hold an appropriate airman’s certificate. Sections 121.378 and 135.435 require that any individual who you put directly in charge of performing maintenance hold an airman certificate.
Section 121.371 requires that any individual that you authorize to perform RII for you hold an appropriate airman certificate. Section 121.709 requires that anyone who you authorize to issue an approval for RTS hold an appropriate airman’s certificate. Your DOM and chief inspector must hold an airman’s certificate with Airframe and Powerplant (A&P) ratings.
NOTE: The certificate requirements contained in the regulations stated above are directed at the air carrier. The certificated airman acting in this position does not exercise the authority or privileges of his or her certificate.
(2) You accomplish all maintenance and approval for RTS on your aircraft under your air carrier certificate by your maintenance organization or persons authorized by you, not by any individual or organization under their own individual certificate. There is, however, one exception to the individual airman certificate requirement. It occurs if you arrange for a certificated repair station (CRS) located outside the United States to perform maintenance. At such repair stations, individuals directly in charge of performing maintenance or required inspections are not required to hold an FAA airman certificate.
5-2. MAJOR REPAIRS AND ALTERATIONS. Under §§ 121.379(b) and 135.437(b), major repairs and alterations must be done in accordance with technical data approved by the FAA.
Part 43, appendix A, contains a list of repairs and alterations that are considered to be major.
Exclusive reliance on the part 43, appendix A, list of major repairs and alterations to make the major/minor classification might result in the misclassification of some repairs and alterations because the part 43, appendix A, list does not include evolving airplane design and construction techniques such as composite structures and the high-speed, high-altitude pressurized jet transport. You should have detailed major/minor classification procedures in your manual to evaluate each repair or alteration on a case-by-case basis using such factors as the certification basis of the aircraft; classification of the structure as primary, secondary, or a primary structural element; or classification as a fail-safe, safe-life, or damage-tolerant structure.
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5-3. AIRWORTHINESS RELEASE FORM OR AIRCRAFT LOG ENTRY AND APPROVAL FOR RTS. After performing any maintenance on your airplane, you must approve it for RTS before you may operate it. As an air carrier, you must issue an approval for RTS under § 121.709 or § 135.443, as appropriate. You can read additional, more detailed information about the process for approving your airplanes for RTS in Chapter 8.
5-4. SCOPE OF MAINTENANCE. You must provide instructions in your maintenance program and maintenance manual for maintenance and alterations. These instructions should address the areas of what to do, when to do it, how to do it, and was it done properly. The three major areas to consider are scheduled maintenance, unscheduled maintenance, and specific maintenance requirements for major components of the aircraft.
a. Scheduled Maintenance. Scheduled maintenance consists of all the individual maintenance tasks performed according to the maintenance time limitations, also called a maintenance schedule. Your scheduled maintenance activities should include procedural instructions for the maintenance tasks and procedures for recording the results of the inspections, checks, tests, and other maintenance. Your procedures should also provide for time-related activities such as recurring ADs, Certification Maintenance Requirements (CMR), and life-limited parts retirement.
b. Unscheduled Maintenance. Unscheduled maintenance includes procedures, instructions, and standards for maintenance that occurs on an unscheduled or unforeseen basis. A need for unscheduled maintenance may result from scheduled maintenance tasks, pilot reports, or unforeseen events, such as high-load events, hard or overweight landings, tail strikes, ground damage, lightning strikes, or an engine over-temperature. In your maintenance manual, you should include instructions and standards for accomplishing and recording unscheduled maintenance.
c. Specific Maintenance Requirements for Major Aircraft Components.
(1) Engine Maintenance Program. Your engine maintenance program should cover the maintenance of installed engines and off-wing engines for each engine model you operate. If your aircraft has auxiliary power units (APU), you may want to include APU maintenance as part of your engine maintenance program. Usually, the installed engine or APU requirements will be contained in the maintenance schedule. In addition to procedural information, the off-wing program described in your maintenance manual should provide shop scheduling information or intervals for cleaning, adjusting, inspecting, testing, and lubricating each part of the engine or APU. You should include in your maintenance manual the degree of inspection, the applicable wear tolerances, and the work required when the engine or APU is in the shop.
(2) Propeller Maintenance Program. If applicable, your propeller maintenance program should cover the maintenance of installed propellers and off-wing propellers for each model you operate. Usually, the installed propeller system scheduled maintenance requirements will be contained in the maintenance schedule. In addition to procedural information, the off-wing program described in your manual should provide shop scheduling information or intervals for cleaning, inspecting, adjusting, testing, and lubricating each part of the propeller system requiring that maintenance. You should include in your maintenance manual the degree
Par 5-4 Page 17 (and 18) of inspection, the applicable wear tolerances, and the work required at these periods. Some modern propellers are constructed of composite materials and, therefore, may require unique tools, repair procedures, and specialized training for your maintenance personnel.
5-5. PARTS AND APPLIANCES MAINTENANCE PROGRAM. For the most part, this section of your maintenance program covers shop operations, which may include both scheduled and unscheduled tasks. You may conduct these shop operations at some location other than where you perform maintenance on your aircraft. Your parts and appliance maintenance program should cover both installed parts and appliances and off-wing maintenance for each part and appliance model that you operate. Usually, the scheduled maintenance requirements for installed parts and appliances will be contained in the maintenance schedule. In addition to procedural information, the off-wing program described in your maintenance manual should provide shop scheduling information or intervals for cleaning, adjusting, inspecting, testing, and lubricating each component of the part and appliance requiring that maintenance. Include in your maintenance manual the degree of inspection, the applicable wear tolerances, and the work required when the part or appliance is in the shop.
Par 6-1 Page 19 CHAPTER 6. MAINTENANCE SCHEDULE
6-1. THE MAINTENANCE SCHEDULE. Sections 119.49 and 121.135(b) require you to have maintenance time limitations, also called a maintenance schedule. These same rules permit you to use standards for determining your maintenance time limitations, which are the regulatory basis of FAA-approved reliability programs. The maintenance time limitations set out the what, how, and when of your scheduled maintenance effort. Although in the past the schedule included only basic overhaul limits and other general requirements, today it includes a specific list of each individual maintenance task and its associated interval. The regulations are broad enough to permit you to organize all of these individual tasks into a series of integrated scheduled work packages of your own design that provide a continuous succession of necessary or desirable scheduled maintenance tasks for your entire airplane.
NOTE: You should not confuse the meaning of the terms “instructions for continued airworthiness” (ICA) required by part 25, § 25.1529, “time limitations” (maintenance schedule) required by § 121.135(b)(18), and “airworthiness limitations” (AL) required by part 25 appendix H, § H25.4.
Although related, each term has a significant meaning within the context of the stated part and section of the regulation.
6-2. THE FAA’s ROLE IN RELATION TO THE MAINTENANCE SCHEDULE. The FAA authorizes your maintenance schedule through your OpSpecs, and your CASS monitors that schedule to verify its effectiveness (i.e., producing the desired results). Your CASS will be your principal source of information that might indicate a needed change to your maintenance schedule. (We describe the CASS in Chapter 11 and in much more detail in the current edition of AC 120-79, Developing and Implementing an Air Carrier Continuing Analysis and Surveillance System.) We expect you to correct any deficiencies in your maintenance schedule. Under §§ 121.373(b) and 135.431(b), if you do not make needed changes, we can require you to change your maintenance schedule or any other element of your maintenance program found deficient.
6-3. MAINTENANCE SCHEDULE CONTENTS.
a. Maintenance Schedule Should Contain the Following Information:
(1) What (Unique Identifier). This is the item that you are going to maintain. Your identifier should be specific enough to allow the individual that you assign to do the scheduled maintenance task to easily and accurately identify the item. The following are examples of items that an operator’s maintenance schedule may include:
• ADs,
• Service Bulletins (SB)/Service Letters,
• Replacement of life-limited items,
• Replacement of components for periodic overhaul or repair,
• Special inspections,
• Checks or tests,
• Lubrication and servicing,
• Tasks identified in the Maintenance Review Board Report (MRBR),
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• ALs,
• CMRs,
• Supplemental Structural Inspection Documents (SSID), and
• Electrical wiring interconnection system (EWIS).
(2) How (Task). This is how you should maintain the item you are going to maintain, or the scheduled maintenance task you will perform. A scheduled maintenance task is a maintenance action that you perform at regular, scheduled intervals. The intent of this task is to ensure the item can continue to perform its intended function, allows you to discover a hidden failure, or to ensure that a hidden function is available. You should not use terms such as hard-time (HT), on-condition, or condition monitored in your maintenance schedule. The maintenance schedule should state the maintenance task to be performed to meet the requirement
(e.g., Replace, Inspect, and Test).
(3) When (Timing). You should accomplish scheduled maintenance tasks (one-time or repetitive) at an acceptable time in service. You may measure time in service in calendar-time, operational hours, flight cycles, or any other appropriate parameter.
b. Maintenance Schedule Objective. Your overall maintenance schedule objective is to do the correct tasks at the correct interval. Keep in mind that more maintenance is not always a good idea, so if you decide to decrease intervals or add tasks, you should go through the same justification process as any other change to the maintenance schedule.
c. Maintenance Schedule Best Practice. For task management, inventory, and audit purposes, you should identify, on the maintenance schedule, the task or work card associated with each scheduled maintenance task. This way you can ensure that you accomplish all of your scheduled maintenance tasks according to your schedule.
6-4. STANDARDS FOR DETERMINING MAINTENANCE SCHEDULES. As we mentioned in paragraph 6-1, §§ 119.49 and 121.135 permit you to have standards for determining your maintenance time limitations. In the past, we used this language as the regulatory basis for FAA-approved reliability programs that evolved during the 1960s. These programs were based on the Air Transport Association of America’s (ATA) now obsolete process-based Maintenance Steering Group—2nd Task Force (MSG-2) decision logic that focused on failure rates and maintaining individual parts of the aircraft. Consistent with the continuous evolution of aviation, MSG–2 became obsolete in 1980 with the advent of the ATAs task-based Maintenance Steering Group—3rd Task Force (MSG-3) decision logic. MSG-3 focused on aircraft systems and a loss of function rather than on an individual part failure. In any case, the management of these MSG-2 process-based programs was actuarial analysis.
Air carriers used the failure rates of a part to determine, through a probability process, the likelihood that the part would have a similar failure rate in the future. The standard was the acceptable failure rate. Air carriers used a failure rate alert program with upper control limits (UCL) and lower control limits (LCL) to track part failure rates. The air carrier was obliged to take action only when the failure rate deviated from the probability-based prediction
(i.e., exceeded the UCL or the LCL). If the part did not respond, the air carrier had authorization to move the UCL or LCL to make the failure rate within the alert program limits.
Par 6-4 Page 21
a. Reliability Centered Maintenance (RCM). During the 1970s, after collecting a large amount of operational data over time, the industry came to the realization that using failure rates and alert programs was not the most effective way of managing scheduled maintenance. Using the vast amount of operational data that was available, United Airlines developed and published a report during 1978 under a U.S. DOD contract entitled “Reliability Centered Maintenance (RCM).” This very significant document was in stark contrast to the previous part failure rate focus. RCM focused on the loss of function of an aircraft system. RCM determined that everything does not fail the same way; failures occur according to six different failure patterns.
RCM also determined that everything does not require the same type of maintenance; there are four different types of scheduled maintenance. RCM also took into account the different consequences (safety, operational, and economic) of a loss of function, as well as system functional redundancy and inherent design safety when determining if scheduled maintenance was required. In some cases, RCM determined that no scheduled maintenance was required. This resulted in doing only required maintenance and a much lower maintenance burden.
b. MSG–3 Decision Logic. The RCM document was the major basis for the ATA’s development of the MSG-3 decision logic in 1980. Since then, most aircraft manufacturers have used the ATA’s MSG-3 decision logic to help them develop scheduled maintenance requirements for their new products. Besides providing organization and flow to the deliberative process, the primary attribute of the MSG-3 process is that the user can develop initial scheduled maintenance requirements without the operational data that is required to determine the need for scheduled maintenance tasks. Using the techniques of the MSG-3 decision logic, it is fairly simple to decide what tasks are required to be included in an initial scheduled maintenance program. However, the MSG-3 decision logic does not contain task interval selection decision logic to help the user determine where to set the task intervals, or how to adjust them after service is initiated. Using the MSG-3 process, initial task intervals are set on the basis of knowledge of the design, and the best judgment of the MRBR working group members. As a result, validation of initial interval selections must occur when the aircraft begins service and starts generating the operational data that was not available when the initial intervals were set.
c. Effective Scheduled Maintenance. An inherent function of your CASS is to determine the effectiveness of your scheduled maintenance effort through operational data collection and analysis activity. You use this important function to determine the level of scheduled maintenance effectiveness and to make the changes necessary to achieve the standard of effectiveness that you have set. Effective means “it is producing the desired results.” Thus, from an operational standpoint, an indicator of effectiveness of your scheduled maintenance effort is the availability of your aircraft for flight operations. If your aircraft are unavailable for flight operations due to maintenance reasons, then your scheduled maintenance program may not be as effective as it should be. There may be other elements of your maintenance program besides the scheduled maintenance element that may be deficient as well, but your CASS procedures will identify the root cause and help you identify and make the adjustments/changes necessary to achieve the level of flight operations availability (the result) that you have set.
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d. MRBR Changes. MRBR revisions are developed to address global in-service experience in addition to reflecting new design configurations and new rules. Therefore, when MRBR revisions occur, you should review them and determine if they necessitate a change in your maintenance schedule based on your particular needs, experience, and program’s goals and philosophy.
e. Failure Effect Categories (FEC). While you may make changes to your maintenance schedule, it is important for you to consider the task FEC that arises from application of the MSG-3 logic used to develop the MRBR (since this helps identify the relative criticality of the task). You should not delete or change the scope of MSG-3 FECs 5 (Evident Safety) and 8 (Hidden Safety) tasks without the concurrence/approval of the FAA Maintenance Review Board (MRB) Chairman and the OEM/type-certificate holder (TCH).
NOTE: To protect the identity and significance of a safety-related task, you should identify each task in your maintenance schedule that is a CMR, AL, or those with FECs 5 and 8.
Par 7-1 Page 23 CHAPTER 7. REQUIRED INSPECTION ITEMS
7-1. RIIs.
a. Tasks as RIIs. Sections 121.369(b) and 135.427(b) require you to designate certain tasks as RIIs. Your RIIs must include at least those tasks that could result in a failure, malfunction, or defect that endangers the safe operation of the aircraft if the task is not completed properly or if you use improper parts or material. If other persons perform maintenance tasks for you, you may authorize them to accomplish your RII requirement, provided that your manual satisfies the regulatory requirements, as outlined in paragraph 7-2.
Consistent with the regulations, you remain primarily responsible for the performance of each RII accomplished by the other person.
b. Making RII Lists. Your RII lists should identify specific items of maintenance for each aircraft type you operate. It is inappropriate to designate entire systems as RIIs. You should adhere to a decision process, similar to the following, when creating a list of RIIs: