AVIATION SAFETY NEWSLETTER
Thought for the month..... If it looks like a duck, walks like a duck,
and quacks like a duck, then it must be a duck…right?
Parts is parts.... Remember the KFC commercial from the '80's where
the phrase "…parts is parts" came from? It was about the same time that the FAA began its crusade on
traceability of replacing parts in aircraft. I still remember that commercial whenever the topic of suspected
unapproved parts (SUPs) is discussed. I also remember the Director of Maintenance at the repair station that I
worked at back then who would add his own caveat to that phrase by appending the phrase with "…except aircraft
Back then, there weren't many people in the maintenance field who had concerns about aircraft parts and their legitimacy. However, that was also about the time when small aircraft manufacturers were shutting down their production lines, and parts production as well. It was becoming increasingly difficult to procure parts to maintain the GA fleet. Many people started to seek nontraditional sources for obtaining replacement parts such as aircraft salvage yards, TAP classified adds, and aircraft fly-ins with swap meets.
The problem may be somewhat lessened today with some small aircraft back into production but it has by no means ended. In particular is the problem of obtaining parts for out of production aircraft, or aircraft engines. It is easy to be led astray by some well-intentioned person who "knows" where to find those hard to find parts.
Not long ago I was reinstalling a cylinder on a Continental C85 after a hydraulic unit was replaced. Checking the valve lash required me to replace the push rod because there was too much clearance between it and the rocker arm. Not being fully familiar with this engine I was working under the supervision of another mechanic who was well versed in the care and upkeep of it. He informed me that there were two oversize push rods available for this engine and I needed the larger size of the two. The parts catalog was not specific and when I called an authorized TCM parts supplier I was told that there was only one oversize available and it wasn't long enough for my needs.
Next, I called direct to TCM and asked them if there was a larger push rod and was told that only the oversize unit previously identified by the supplier was available. But, they informed of an additional source for a larger size push rod, so I called them. They told me that they did have the size I was looking for. Then I dropped the "A" question on them. I asked if it was an "approved" aircraft engine part. Their answer was that it was manufactured for a Teledyne Continental "ground power" engine (read this as NO). I am sure that I would not have been provided that information unless I asked the question. If I purchased the push rod and installed it into the engine I would have been using an unapproved part for a type-certificated engine.
This parts source is a recognized engine parts supplier who advertises in a leading aircraft parts periodical. The FAA tells us that we should know our suppliers and buy parts from known legitimate parts suppliers. Just the same, we cannot assume that is a solid guarantee that we will only get legitimate aircraft parts from them. When something doesn't seem right we have an obligation to ask the difficult questions. I knew that the supplier that I was dealing with was not a parts source sanctioned by Continental. That fact by itself did not mean that any parts supplied by them were suspect. But, when other sanctioned parts suppliers were not aware of the odd size push rod,I knew I had to be cautious of the part.
The people who are in the aircraft parts supply business are not regulated, controlled, or surveilled by the FAA. They are free to sell their goods without informing their customer whether or not the part is approved for type-certificated aircraft. It is up to us, the consumer, to be sure that what we purchase is approved for installation in our aircraft.
For those who wondered how I corrected the lash problem. It seems the rocker arm was worn too much, so I replaced it instead of the push rod. As it turned out, the push rod that I almost bought and installed really wasn't all that it was quacked up to be-was it?
August 16th & 17th
Flight Instructor Renewal Clinic
Greater St. Louis Flight Instructors Association
FIRC at Linn Tech., Linn, MO
Renewal for CFI's due in Aug. thru Nov.
FITS and GPS for IFR and VFR
Hangar 1 at CPS
7th Annual Helicopter Safety Seminar
Mid Coast Aviation Training Center
8 AM to 3 PM
GOOD MAINTENANCE IS NO ACCIDENT
Airworthiness Safety Program Manager
1-800-322-8876 extension 4830