What is up with these Unapproved Parts Notifications that I receive from the FAA? (For a list of UPNs issued since the UPN program began in the early 1990s, see www.faa.gov/avr/sups/ upn.cfm.)

UPNs tell an interesting story, starting with the affected product and an explanation for why the UPN was issued. The meat of the UPN is the Background section. Here the FAA explains that a maintenance organization or mechanic has done something wrong. Because of the companies’ or the mechanics’ errors, basically everything they touched is now suspect and likely unairworthy.

There are issues raised by these UPNs, from what to do with them and how to interpret their advice to how they are generated and why some companies or mechanics get UPNed to what should a mechanic or inspector do with a UPN.

Here is a UPN that I received a few months ago on Lycoming engines: "Information received during a recent FAA suspected unapproved parts investigation revealed that Larry Good (Good Aviation... Moore, OK) improperly approved for return to service Lycoming engines used on general aviation aircraft."

According to the UPN, Larry Good perpetrated some heinous maintenance practices, including: "use of scrap parts marked ‘NOT AIRWORTHY’ and parts with identification data removed;" made false logbook entries regarding the use of new parts that were used; used replacement parts beyond manufacturer service limits; performed repairs and overhauls without acceptable or approved data; approved engines for return to service that were not in compliance with ADs; and installed wrong-size main bearings and incorrect cylinders.

This reads like a summary of bad mechanic behavior, and if it is true, it is scary to think work of such terrible quality is out there.

But the above list also raises tons of questions, yet the UPN doesn’t begin to answer them. I wonder:

1. What does "scrap parts marked ‘NOT AIRWORTHY’" mean, exactly? "Not airworthy" in this case means that someone at sometime felt that a part was unairworthy and made some mark on the part. Any properly certificated mechanic or repair station could, theoretically, inspect such a part and, using acceptable and/or approved data, determine that the part was airworthy.

2. How does the FAA know that the parts it says are used were in fact not new? I’d like to know how this was determined. The same goes for parts beyond their service limits. How does the FAA know that the parts weren’t right at or near the service limit when they were installed?

3. Did Larry Good not have acceptable or approved data? The FAA doesn’t say, just that the work was done "without" the data. The data issue for Lycoming engines is murky. Some Lycoming overhaul manuals have not been updated since the early 1970s. Lycoming says that its service bulletins act as de facto overhaul manual updates. Was Larry Good not using the overhaul manual, not referring to service bulletins, or not in possession of any data at all?

The curious part of this UPN is the FAA’s recommendation for those who received this notice. We are to inspect "aircraft, aircraft records, and/or parts inventories for engines approved for return to service by Larry Good." If found, we should "inspect the engine parts and components for conformity, inspect the validity of engine logbook entries" and "report any evidence of engine failure, metal in the oil screen, overheating, or other improper maintenance to the FAA..."

Okay. If I’m doing an annual inspection or maintenance, I have to read the entire logbook to see if there is any reference to engine work done by Larry Good. What if I can’t read Larry’s handwriting? What if Larry overhauled the engine 10 years ago and it runs fine? What if I find out that Larry did the overhaul? Is the airplane unairworthy? No, not necessarily. A UPN is not a mandatory FAA document. Compliance is optional.

By what criteria did the FAA determine that parts in Larry Good engines are unairworthy? And what criteria should a mechanic use when trying to evaluate the airworthiness of a Good-powered airplane?

These UPNs are not just for the little guys; they apply to any kind of aircraft. Do your inspectors regularly review UPNs? If not, perhaps they should check the UPN web site for possible unapproved parts. And if you should happen to be targeted by a UPN, good luck, because there doesn’t appear to be much legal recourse available if your name gets spread all over the aviation universe for what might be subjective reasons.