So if you don't inspect per the "All Model AT-6 Series Aircraft" on your T-6G, how do you know that a surplus one-piece horizontal stabilizer bracket was not installed (50-09-01 horizontal stabilizer rear spar connection cracked fittings) by a previous owner/operator? You better make sure that if a replacement part was ordered from Lance Aircraft Supply (where you can get either kind) or found in a trash dump and reused, it is either the later part called out in the IPB or it has been modified per the AD note/NAA bulletin. As the IA, you are responsible for airworthiness, not the previous guy who signed off the airplane with the generic statement "all AD notes complied with."
I have seen logbooks with signatures by IAs that an AD note has been complied with, when the compliance has been maintained out through replacement parts. Year after year IAs assumed that something is in compliance because someone signed it off as in compliance years earlier.
You have to look at how the FAA approaches these things. They deal mostly with new aircraft of known configurations.
A little birdie from an aircraft manufacturer told me:
Quote:
The specific language would have to be looked at in each AD to determine if it is a regulatory requirement to accomplish the AD. You did that and found that T-6G is not in the required effectivity. In theory, if the airplanes were all a progression of FAA approved designs, they would have unsafe conditions from the previous model designed out of the next model. Otherwise they could not qualify for approval of the new model. With this surplus military to civilian FAA approval process, and the possibility of a less prescriptive environment of these old surplus airplanes, I think your concern is valid that there’s exposure for issues to either not be addressed on the T-6G by the FAA or for an issue to be re-introduced by operators.
If I owned a T-6G, I would assess each AD and all the T.O.s I could get my hands on, and build a maintenance and inspection program base on all of the available information. This latest issue of the wing attach angle was covered in earlier models by not only that old AD, but also by the Air Force in a T.O.. So, learning what’s in the T.O.s and ADs for these other models might keep you out of trouble. If there is a replaceable component that had a fix or prohibition which might be re-introduced, I’d put it on the Annual Inspection checklist. If the design of the T-6G is the same or enough of a similar design, I’d also put the requirement in my maint/Insp program. Our airline operators also encounter similar issues and the FAA has encouraged a similar philosophy.