Certification Maintenance Requirements



AAC No.2 of 2011 dated 30.09.2011 describes non inclusion CMR in AMP as level 1 finding. Para 6 of appendix 1 quotes “Airworthiness limitation Items (ALI / AWLI) / Certification Maintenance Requirements (CMR) items are not included into Aircraft Maintenance program (AMP) shall be treated as level 1.If they are not identified in the AMP, then it is level 2. CMR* (task interval cannot be adjusted) Items are not carried out within the specified time limit, shall be treated as level 1. In case of CMR** (Task interval can be adjusted) items not carried out within the specified interval should be level 2’’.

CAR 145.A.95 (a) : A level 1 finding is any significant non-compliance with CAR -145 requirements which lowers the safety standard and hazards seriously the flight safety.
CAR 145.A.95 (b) : A level 2 finding is any non-compliance with the CAR-145 requirements which could lower the safety standard and possibly hazard the flight safety.
A CMR is a required periodic task established during the design certification of the airplane as an operating limitation of the type certificate. Certification Maintenance Requirements are a subset of the tasks identified during the type certification process. CMR’s usually result from a formal, numerical analysis conducted to show compliance with catastrophic and hazardous failure conditions.
A CMR is intended to detect safety-significant latent failures that would, in combination with one or more other specific failures or events, result in a hazardous or catastrophic failure condition.
 CMR’s are derived from a fundamentally different analysis process than the maintenance tasks and intervals that result from Maintenance Steering Group (MSG-3) analysis associated with Maintenance Review Board (MRB) activities. MSG-3 analysis activity produces maintenance tasks that are performed for safety, operational, or economic reasons, involving both preventative maintenance tasks, which are performed before failure occurs (and are intended to prevent failures), as well as failure-finding tasks. CMR’s, on the other hand, are failure-finding tasks only, and exist solely to limit the exposure to otherwise hidden failures. Although CMR tasks are failure-finding tasks, use of potential failure-finding tasks, such as functional checks and inspections, may also be appropriate.
CMR’s are designed to verify that a certain failure has or has not occurred and do not provide any preventative maintenance function.  The CMR task interval should be designated in terms of flight hours, cycles, or calendar time, as appropriate.
CMR’s should not be confused with required structural inspection programs that are developed by the type certificate applicant to meet the inspection requirements for damage tolerance

Comments

R Monsang said…
Sir, can you post a sample CMR task procedure. I want to how it is different from the MPD task.
October 2, 2011 at 8:45 AM
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