The FAA has withdrawn a policy memorandum that would have essentially defined “engine influencing parts.” The decision to drop the memo came at the request of the Aeronautical Repair Station Association (ARSA) and Airlines for America. The associations in October wrote the agency objecting to the memorandum, saying it incorrectly defined engine influencing parts by erroneously relying on an Advisory Circular providing guidance on life-limited engine parts.

Noting that policy memoranda should not create new regulation, the associations said the term "'engine influencing parts' is not defined and it should not be added.”

In response last month, the agency noted that “additive manufacturing is a new and novel technology without current statute, regulation, guidance or industry-wide accepted standards," but added, “We have removed this policy memorandum from the FAA's Regulatory and Guidance Library website.” It also stated the agency would coordinate future policy on additive manufacturing (aka 3D printing). ARSA warned that this means “maintenance providers must remain attentive to continued attempts to constrain parts production.”

The aviation organizations joined several other groups in the summer of 2015 in pushing back on an attempt by Congress to mandate identification and marking of "influencing parts," saying such a requirement would have been duplicative and only serve to further burden FAA and industry resources.