PROCEDURES FOR ANALYSIS OF EFFECTIVENESS OF AN AOC HOLDERS APPROVED AIRCRAFT MAINTENANCE PROGRAMME

Objectives of An Aircraft Maintenance Programme

The objectives of an efficient aircraft maintenance programme are:

• To ensure the realization of the Inherent Safety and Reliability Levels of the Equipment

• To restore Safety and Reliability to their Inherent Levels when Deterioration has occurred

• To obtain the information necessary for Design Improvement of those Items whose Inherent

Reliability proves inadequate.

• To accomplish these goals at a Minimum Total Cost, including Maintenance Costs and the Costs of

Resulting Failures

Analysis of the effectiveness of an AOC holder approved aircraft maintenance Programme as required by Nig. CARs Part 9.4.1.2(a)(5) should be documented in MCM Section 3.5 and implemented.

There are two basic questions the regulations intend an Analysis of Effectiveness of the Maintenance Programme to address:

(1) Are you following your maintenance programme as you have documented in your maintenance control manuals and procedures? This portion should consist of conducting audits and analyzing audit findings and trends to verify that you are following your maintenance programme as you have written it and are properly performing maintenance on your aircraft. The analysis conducted should also identify weaknesses, if any, in the systems and procedures used to carry out your maintenance programme.

(2) In following your MCM and AMP, are you producing the results that you want? The analysis of the effectiveness of the maintenance programme refers to the process of collecting and evaluating operational data that you need to verify that your maintenance programme is producing the desired results.

There are two desired results:

(a) Primary desired results should be those required by Nig.CARs Part 9.4 There are three:

1. You, or any of your maintenance providers, perform all maintenance, preventive maintenance, and alterations in accordance with your MCM.

2. You and your maintenance providers provide competent personnel and adequate facilities and equipment for the proper performance of maintenance, preventive maintenance, and alterations.

3. Each of your aircraft released to service is airworthy and properly maintained for operations in air transportation.

(b) The secondary desired result is that your aircraft operate with a level of reliability that is consistent with the goals of your maintenance programme. “Reliability” is a broad term in this context and is an expression of dependability and the probability that an item, including an aircraft, engine, propeller, or component, will perform its required function under specified conditions without failure, for a specified period of time.

Testing for effectiveness usually consists of collecting and analyzing operational performance data, such as:

• Maintenance-related delays and cancellations,

• Failure rates of parts and components after they are approved for return to service,

• Discrepancy rates of aircraft after heavy maintenance, and

• Related trend analysis.

Collecting Operational Data.

The main tool for determining whether your maintenance programme is effective is to collect and analyze operational data that shows the availability of the equipment, which should be one of the objectives of your maintenance programme. You should collect data that measures the output of your maintenance programme. A primary function or output of your approved maintenance programme is to permit your equipment (aircraft) to continue to do what it is supposed to do. Therefore, any activity (data) that shows that your equipment is not available to do what it is supposed to do would be a prime indicator of the level of maintenance programme effectiveness. The level of unscheduled maintenance is such an indicator. Other indicators that may be reflected in a requirement for unscheduled maintenance are maintenance personnel not following the methods, techniques, and procedures in your manual; facilities and equipment not being adequate for the work that is being performed, and an aircraft being released to service when it is not airworthy.

Types of Operational Data.

Collect data consistent with your operational requirement and useful. Use an effective selection and periodic review process. Do not collect specific data elements that you would not use and that may not fit your particular situation. You can collect operational data from two different activities: routine or unplanned (non-routine) maintenance. However, you should keep any operational data that you collect from any unscheduled work occurring because of planned/routine work separate from the data that is not a result of planned/routine activities. Non-routine/unscheduled maintenance occurring as a result of scheduled, planned maintenance activities is a normal activity. This is the time when you should find discrepancies, and when you should accomplish the identified maintenance, not when your aircraft are in an operational status carrying passengers and/or cargo.

(a) However, you should not consider unscheduled maintenance activities occurring when your airplane is in an operational status carrying passengers and/or cargo as a normal and acceptable activity. After all, a primary function of your scheduled maintenance programme is to permit your airplane to be available for operations in air transportation. Logically, a reduction of availability of your aircraft to carry passengers and/or cargo as a result of unscheduled maintenance activities is a primary indicator of the level of effectiveness of your maintenance programme.

(b) Some examples of routine operational data are:

• Corrosion prevention and control programme findings,

• Repair assessment findings,

• Engine Condition Monitoring (ECM) information,

• Scheduled structural inspection findings,

• Repairs accomplished as a result of scheduled structural inspection findings,

• Scheduled maintenance findings,

• Repairs accomplished as a result of scheduled maintenance findings,

• Vendor or maintenance provider information,

• Component teardown reports, and

• Individual component failure rates.

(c) Examples of non-routine data are:

• Pilot reports, including maintenance deferred in accordance with the minimum equipment list (MEL)/Configuration Deviation List (CDL);

• “Chronic” systems that have repeat write-ups in a specified time period (for example, 10 to 15 days);

• Flight delays and cancellations related to maintenance issues;

• Service Difficulty Reports (SDR); and

• Unscheduled parts replacement or unscheduled maintenance.

(d) Operational data also includes reactive data collection and analysis responding to such non-routine events as:

• Accidents and incidents;

• High-load events such as hard landings, turbulence, etc.;

• In-flight engine and propeller separations and uncontained engine failures;

• In-flight engine shutdowns;

• In-flight propeller featherings;

• Lightning strikes;

• Unscheduled landings caused by mechanical difficulties or malfunctions; and

• Rejected take-offs’ caused by mechanical difficulties or malfunctions.

Analysis of Operational Data.

This section should also indicate by whom and how this data is analyzed, what is the decision process to take action and what kind of action could be taken.

This may include:

 — amendment of the maintenance Programme,

 — amendment of maintenance or operational procedures,

— etc.)

The procedures should:

(1) Provide your analysts with an understanding of the potential significance of each data set and how to process the data to understand its significance. This may require:

• Statistical analysis, such as comparing the frequency of certain events or equipment failures with a determined norm; or

• Qualitative analysis, to evaluate reports of certain types of events.

NOTE: This process is not necessarily the same as that used in an approved reliability programme.

(2) Emphasize that analysis of operational data should consider root causes of negative trends or anomalies. This preliminary RCA, including human factors, may require collaboration with technical personnel in the affected areas or specialists in engineering and reliability departments.

(3) Delineate the roles of your analysts as well as other departments or personnel in the analysis of operational data. You may decide to select a system that uses alerts or warnings if results of your analysis exceed certain predetermined parameters. However, your procedures should not rely completely on such alerts to the exclusion of your analysts’ judgment. In addition, the use of alerts has historically been associated with parts and their failure rates, while current maintenance methodology focuses on systems and the loss of function, not part failure rates. The regulator’s expectation of your policy and procedures in this regard is that you have a complete, written procedure to review and analyze the operational data collected and to determine when a further review is necessary.