In 1992, back in my FAA days, I asked an FAA attorney, “Why are the regulations written so vaguely?” “You mean debatable,” he said. “The Federal Aviation Regulations are comprehensive. Before applying the regulations to a specific issue, a debate should occur. Through debate, the correct application should become obvious.” Following that conversation, whenever I perceived that what we were doing might not be correct, I would initiate a debate on the subject. Debating the regulations among professionals is a good thing.
Debating can be educational. Everything we have done becomes experience. Experience becomes knowledge. Education equates to sharing our collective knowledge. Our ability to acquire knowledge becomes our ability to respond correctly to any situation. In aviation, ignorance can be lethal. The best investment we will ever make is in knowledge.
Be careful when debating. Never allow another opinion to evoke an emotional response. It is normal to dislike contradiction. Remember, the intended propose of a debate is to convince or be convinced. One way or the other, we need to end up in agreement. Most importantly, keep in mind that we must prioritize safety.
Bill O’Brien, national resource specialist for the FAA in Washington, D.C., is my best friend in the FAA today. I respect and admire his knowledge and abilities. In the March 2006, issue of AMT Magazine, Bill posted the answers to 20 questions from his proposed “Professional Mechanic’s Test.” I would like to initiate a debate on his first question and answer. Please keep in mind that what I say is not policy, but the personal opinion of an old mechanic and retired FAA inspector.
Bill O’Brien’s question one: “What is the major difference in maintenance record entries between PMA and TSO parts?”
BillO’Brien’s answer: “A parts manufacturer approval part (PMA) is identical to an individual TC part in every way, so it is considered a direct replacement part for OEM parts. For example, if you change a Piper PA-23-250 nose gear actuator with a PMA nose gear actuator, that action only requires a logbook entry under section 43.9. On the other hand, a Technical Standard Authorization (TSO) part is a generic part, like tires, communication and navigation equipment, seat belts, instruments, etc., that could be used on many different makes and models of aircraft. In many cases, installing a TSO part “may” require a Form 337 because installing it would be considered a major alteration of the original type design. For example, installing a new TSO glass cockpit in a Cessna 172 would require a Form 337.”
Respectfully, my answer to question No. 1 is exactly opposite of O’Brien’s. I believe traceability is required for safety. The purpose of aircraft maintenance records is documentation of compliance and traceability. While PMA is quality assurance, TSO is similar to a TC for parts the aircraft manufacturer normally purchases.
All parts (OEM, TSO, and PMA) installed on type-certificated products require FAA approval by make and model. When identified on the TC, TSO parts are considered OEM parts. The type design identifies parts by part number. To be airworthy, an aircraft must conform to the type design and condition for safe operation. Type design establishes the approved parts, and condition represents wear, corrosion, defects, and damage. Aftermarket PMA parts are not permitted use of the same part number as on the TC. Therefore, I contend that installation of an aftermarket PMA part would be a major alteration requiring traceability documentation (Form 337).
Parts Manufacturer Approval
How to tell a good part from a bad one.
A Look at FAR 21.303(a): The Legacy of Administrator vs. Pacific Sky Supply Inc.
The answers to the professional mechanics test that O’Brien promoted in the last issue as a way to gain much-needed recognition for mechanics as a “professional” career field are provided. And...
PMA parts undergo the same rigorous approval and quality control process as OEM parts. The FAA oversees the production of both in the same manner.