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MARPA Air Carrier Committee Seeks Clarification on post-AD PMA Parts

The MARPA Air Carrier Committee, led by Michael Rennick, Delta Air Lines Component Engineering Manager, is hard at work supporting PMA users and MARPA members.  In June, members of the MARPA Air Carrier Committee, including Air Wisconsin, American Airlines, Republic Airways, US Airways, Air Canada, and Delta Air Lines, submitted to the FAA a letter seeking clarification on the issue of PMA parts that are alternates to post modification Airworthiness Directive (AD) related parts.

This clarification is necessary because confusion has sometimes arisen between operators and local regulators over the need for an Alternative Method of Compliance (AMoC) for post-modification AD-related PMA parts.  It is the position of the MARPA Air Carrier Committee that if the PMA is an alternate to an OEM part contained in a post-AD configuration, no such AMoC is required.

When a PMA is issued for a replacement part for a post-modification AD-related OEM part, it is uncommon for the PMA applicant to request an AMoC to the AD, or for the FAA to note the AD on the PMA approval.  This makes some sense because a post-AD PMA part is inherently an alternative method of compliance without being described as one. However, an issue arises because many ADs call out only the modified OEM part as a means of compliance.  Because ADs are technically regulations under Part 39, alternate approvals such as PMAs might not satisfy the regulatory requirement and so an AMoC may be required.

It would be beneficial to both operators and PMA manufacturers to see this change.

The OEM part is the source of the condition giving rise to the AD.  The post-modification part must resolve the condition in order to satisfy the AD. During the PMA approval process for the same part, the AD is also taken into consideration..  In order to receive PMA approval, the subject PMA part must resolve the condition resulting in the AD, just as the post-modification OEM part does.  There should be no need to call out an AMoC for the PMA part related to the AD; the underlying condition that necessitated the AD has changed because the approved PMA part has replaced the post-AD OEM part. The PMA should be a valid terminating action for the AD.

There are limited circumstances in which this reasoning may not apply, but these limited circumstances are not the subject upon which the Air Carrier Committee seeks clarification.  For instance an AMoC may be necessary in a scenario in which an AD applies to a higher level component or assembly. In this scenario the PMA replacement for the OEM part may not address the AD for the higher assembly because it is a replacement at the piece-part level, and thus an AMoC may be necessary for the higher assembly.

Generally, however, an AMoC should be inherent in an approved PMA part and therefore unnecessary as a separate approval.  This is the policy clarification that the Air Carrier Committee seeks in the form of a formal FAA communication.  If an approved PMA part is a replacement for a post-AD OEM part, the FAA’s policy should clearly state that the approved PMA is a terminating action for the AD and that no additional approval or discrete AMoC is required. In the alternative, an AMoC could automatically issue for each post-AD PMA to show compliance.

MARPA greatly appreciates the Air Carrier Committee’s work on this project.  MARPA will be working with the FAA and the Committee to determine whether future ADs will list an approved PMA as a valid terminating action, or whether an automatic AMoC should automatically issue with a PMA to show compliance to the AD, or some other solution is desired.  We will keep our members apprised of these developments.

If you are a MARPA member air carrier and want to get involved with the Air Carrier Committee, please email Katt Brigham at katt@washingtonaviation.com.  If you are not yet a MARPA member but would like to get involved, visit our membership application page.  MARPA membership is free for air carriers!

Edited to clarify that ADs are regulations and identify possible solutions to the issue raised in the Air Carrier Committee’s letter.

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