NTSB decision rules that SB's are manadatory...

I think the question for the A&P though is "on what basis did you
overhaul the engine?". If the A&P did not use the manufactor's
instructions to overhaul the engine, did he just make it up as he went?
If he's coming up with his own methods of overhauling engines, does he
have engineering data behind him showing that it meets safety
requirements? I think this is more than just following SBs, its trying
to invent new ways of overhauling engines instead of using the Lycoming
instructions. When I overhaul my engine I expect it will be done in
compliance with Lycomings instructions.

-Robert



Dave S wrote:
http://www.avweb.com/eletter/archive...ll.html#192405

The FAA dinged an A&P for not complying with a "mandatory" SB prior to
returning an aircraft to service in a part 91 environment. The NTSB
upheld it, breaking with decades of precedent.

Robert M. Gary wrote:
I think the question for the A&P though is "on what basis did you
overhaul the engine?". If the A&P did not use the manufactor's
instructions to overhaul the engine, did he just make it up as he went?
If he's coming up with his own methods of overhauling engines, does he
have engineering data behind him showing that it meets safety
requirements? I think this is more than just following SBs, its trying
to invent new ways of overhauling engines instead of using the Lycoming
instructions. When I overhaul my engine I expect it will be done in
compliance with Lycomings instructions.

That's basically correct, but has some interesting connotations. A
field overhaul is a repair, not an alteration. This means that
Lycoming (or, in effect, any manufacturer of any airframe, engine, or
accessory) can at any point change its mind about what constitutes an
acceptable repair. Thus, you can fly with it as it is until you need
to fix it, but once you need to fix it, the manufacturer can force you
to comply with any SB. Essentially, the NTSB has ruled that the
manufacturer can at any point decide that repair procedures that were
acceptable before are no longer acceptable.

For example, Lycoming has a list of items that can't be reused when the
engine is overhauled. It could issue an SB saying the crankshafts of
certain (or all) engines must be replaced at overhaul, and whether the
FAA makes it an AD or not, it doesn't matter - you can't overhaul the
engine without replacing the crankshaft. In effect, the crankshaft is
added to the list of non-reusable items. Not that anything like this
would happen...

What this decision does is shift the power balance away from the
individual A&P and towards the manufacturer - which of course only has
your best interests at heart, and would never make you discard a part
just so it could sell you a new one.

One more reason I will never again purchase a certified aircraft.

Michael