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
Parts manufacturer approval (PMA) is basically a quality assurance procedure. Order 8110.42B describes the procedures for evaluating and issuing a PMA for replacement and modification parts on type-certificated products. Although approved as replacement parts, aftermarket PMA parts are not necessarily identical to OEM parts. In some instances, the aftermarket PMA part has proven to be an improvement.
Technical Standard Orders
Technical Standard Orders (TSO) is a minimum performance standard. An example would be TSO-C22g, Safety Belts. This TSO prescribes the minimum performance standard that safety belts must meet in order to have the applicable TSO marking. However, to qualify for placing the TSO marking on a part, you must be the holder of the TSO for that part, just as the aircraft manufacturer is the holder of the TC for the aircraft. The most important details to remember about TSO parts is they must have the applicable TSO marking, and they must be specifically approved for installation on the make and model type-certificated product.
Sometimes a TSO may have hundreds of variations such as TSO-C62d, Tires. What approval do you need for the tires on an aircraft? Tire requirements are aircraft performance related. The aircraft maintenance manual should tell you. The Cessna 172 maintenance manual may only specify size and ply rating, while the Cessna Citation maintenance manual may be more specific.
What TSO markings should a tire have? Each tire must be legibly and permanently marked with at least the following:Applicable TSO number, brand name, and the name or registered trademark of the manufacturer responsible for compliance, the speed rating, load rating, size, skid depth, serial number, date, manufacturer’s part number and plant code, and if appropriate, nonretreadable.
Can you fabricate a TSO part? Special Airworthiness Information Bulletin Number ACE-96-01 says, “Hose assemblies may be fabricated by a mechanic utilizing TSO-C53a Type C or D material.” However, if you do that you will end up with a Suspected Unapproved Part (SUP). If you do not hold the TSO, you will have to fill out a Form 337, and with your materials documentation, take your fabricated hose assembly, complete with your new fire-resistant TSO markings identifying you as the manufacturer, to a MIDO or FSDO for FAA approval prior to installation on the make and model type-certificated product.
It’s About Traceability
Traceability is required for ADs. If a part proves to be defective, we need to know where to find and replace or modify parts of the same design from the same manufacturer.
Some time ago, the FAA seemed to relax its documentation requirements for installing other than OEM parts. Part of the reason may have been the ever-increasing workload of processing all those Form 337s for a growing aftermarket business. However, our need to know who made the parts installed in a type-certificated product remains.
Here’s a suggestion. Rather than eliminating traceability, just eliminate the workload. The FAA owns a simple computer program referred to as Program Tracking and Reporting Subsystem (PTRS) that filters and feeds data into a Paradox database. One simple page of that subsystem could easily be developed and made accessible via the Internet and the local FSDO and MIDO for documenting the installation of aftermarket PMA parts. This would eliminate the workload associated with processing all those Form 337s, and traceability efficiency would be tremendous. Retrieving information from a Paradox database is easy and fast. The savings to the public would also be tremendous.
What if the FAA knew which aircraft had which parts installed? I believe the applicability portion of an AD, as well as the mailing list, would be different. Read the applicability portion of any AD from the 1950s, 1960s, or 1970s, and then read the applicability portion of AD 2005-26-10. See what a difference eliminating traceability has made?
Alternative methods for traceability could be: bar coding, a ColdFusion form on the FAA’s website, or a traceability registration card requiring the PMA holder to identify where its parts are installed. Years ago I even envisioned bar coding on aircraft registrations and airmen certificates. Think how useful this could be. The mechanic or repair station could scan their certificate, scan the aircraft registration certificate, and scan the OEM, PMA, or TSO part bar code, and “poof” the FAA would know who put what where when and why — resulting in improved safety and reduced workload for both the mechanics or repair stations, and the FAA. If any parts prove to be defective, finding and replacing them would be “a piece of cake.”
With respect to aircraft maintenance records, maintenance recordkeeping prompted a 1995 FAA debate concerning who is responsible for AD compliance and recordkeeping. The aircraft in question turned out to be “somewhat airworthy,” but you couldn’t tell that from the aircraft maintenance records. Among other discrepancies, a dyslexic mechanic had inverted a recurring AD number, effectively changing it from a Cessna AD to a Piper AD, and four other mechanics had copied the Piper AD number and signed it off as being complied with at each of six annuals. I wrote five mechanic Letters of Investigation and 11 pilot Letters of Investigation. Well … “The ship hit the sand.” By the way, you cannot sign off a recurring AD like this, “C/W AD ##-##-##.” I will explain “somewhat airworthy” in another article.
Ok, I have expressed my opinion on PMA, TSO, OEM parts and maintenance records. Now it is your turn in this debate. Send your opinion and/or comments to AMT Magazine. I hope my best friend Bill O’Brien responds as well. People new to aviation learn a lot when old-timers debate. In addition, you may ask me any question you want, and if it is a good one, like Bill O’Brien’s question No. 1, I may write an article on the subject.