EASA Regulatory Drivers for Reliability & Defect Control

Sofema Online (SOL) www.sofemaonline.com considers the regulatory requirements related to the management of Defect Control & Reliability.

Introduction – AMC M.A.301(b) Continuing airworthiness tasks (ED Decision 2020/002/R)

» The operator should have a system to ensure that all defects affecting the safe operation of the aircraft are rectified within the limits prescribed by the approved minimum equipment list (MEL), configuration deviation list (CDL) or maintenance data, as appropriate.
» Also, that such defect rectification cannot be postponed unless agreed by the operator and in accordance with a procedure approved by the competent authority.

(Consider the Role of MEL Extension Procedure – if available in your organisation what is the applicable criteria – discuss)

» When deferring or carrying forward a defect rectification, the cumulative effect of a number of deferred or carried forward defects on a given aircraft and any restrictions contained in the MEL should be considered.

(How does this happen in your organisation – how can you demonstrate this?)

» Whenever possible, deferred defect rectification should be made known to the pilot/flight crew prior to their arrival at the aircraft.

(How does this happen in your organisation if not what is the challenge? – If yes, how can you demonstrate this?)

» In the case of aircraft used by air carriers licensed in accordance with Regulation (EC) No 1008/2008 and of complex motor-powered aircraft, a system of assessment should be in operation to support the continuing airworthiness of an aircraft and to provide a continuous analysis of the effectiveness of the CAMO defect control system in use.
» The organisational system should provide for:

o Significant incidents and defects:

- To monitor incidents and defects that have occurred in flight and defects found during maintenance and overhaul, highlighting any that appear significant in their own right.
- Repetitive incidents and defects: monitor on a continuous basis defects occurring in flight and defects found during maintenance and overhaul, highlighting any that are repetitive.
- Deferred and carried forward defects: Monitor on a continuous basis deferred and carried forward defects. Deferred defects are defined as those defects reported in operational service which are deferred for later rectification. Carried forward defects are defined as those defects arising during maintenance which are carried forward for rectification at a later maintenance input.
- Unscheduled removals and system performance: analyse unscheduled component removals and the performance of aircraft systems for use as part of the maintenance programme efficiency.

General Note - For complex motor-powered aircraft, when the AMP is based on maintenance steering group logic or on condition monitoring, the AMP shall include a reliability programme.

Concerning Reliability Program AMC M.A.302(g) Aircraft maintenance programme ED Decision 2020/002/R

» Reliability programmes should be developed for aircraft maintenance programmes based upon maintenance steering group (MSG) logic or those that include condition monitored components or that do not contain overhaul time periods for all significant system components.
» Reliability programmes need not be developed for aircraft not considered complex motor-powered aircraft or that contain overhaul time periods for all significant aircraft system components.
» The purpose of a reliability programme is to ensure that the aircraft maintenance programme tasks are effective and their periodicity is adequate.
» The reliability programme may result in the escalation or deletion of a maintenance task, as well as the de-escalation or addition of a maintenance task.
» A reliability programme provides an appropriate means of monitoring the effectiveness of the maintenance programme.

Appendix I to AMC M.A.302 and M.B.301(d) gives further guidance. (6.5.6.2. Analysis and Interpretation.)

» The procedures for analysis and interpretation of information should be such as to enable the performance of the items controlled by the programme to be measured; they should also facilitate recognition, diagnosis and recording of significant problems.
» The whole process should be such as to enable a critical assessment to be made of the effectiveness of the programme as a total activity. Such a process may involve:

o Comparisons of operational reliability with established or allocated standards (in the initial period these could be obtained from the in-service experience of similar equipment of aircraft types).
o Analysis and interpretation of trends.
o The evaluation of repetitive defects.

Concerning Engineering Analysis and Interpretation

» The range and depth of engineering analysis and interpretation should be related to the particular programme and to the facilities available. The following, at least, should be taken into account:

o Flight defects and reductions in operational reliability.
o Defects occurring on-line and at main base.
o Deterioration observed during routine maintenance.
o Workshop and overhaul facility findings.
o Modification evaluations.
o Sampling programmes.
o The adequacy of maintenance equipment and publications.
o The effectiveness of maintenance procedures.
o Staff training.
o Service bulletins, technical instructions, etc.

Sofema Aviation Services (www.sassofia.com) and Sofema Online (www.sofemaonline.com) offer EASA Regulatory Compliant and Vocational Training across a range of Aviation Areas including a 2-Day MCC Defect Control Process training. For additional details, please see our websites or email Team@sassofia.com