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Old November 28th 06, 01:02 AM posted to rec.aviation.piloting
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Default Get a ferry permit, or just fly it?


Newps wrote:
Robert M. Gary wrote:



My bet is that the permits were created as a legal loophole so the FSDO
couldn't strand your plane in some remote area that wasn't capable of
performing the required maintenance. Once the FAA uses the
"unairworthy" word a pilot is otherwise stuck. Those of us who have
done some bush flying have had situations where we've needed to fly
"unairworthy" planes out of remote areas.


Absolutely. And some of us just don't care. Helped a buddy who taxiied
his Cub into a hole that bent one of the prop blades. We used a 5 pound
mallet and a wooden wheel chock to pound it more or less back into shape
so he could fly it the 30 miles back home. He said it vibrated pretty
good on the way back home but who cares?


He would have, if the crank had busted or he'd lost part of that
prop blade. Blades often crack when bent beyond certain angles-per-unit
of blade span, and a cracked blade will often let go and leave the rest
so unbalanced that the whole engine is torn from the airplane. CG moves
way aft and it won't even glide. It has happened. Propeller bolts are
known to crack, as well.
And you *would* have cared, too, trying to explain to his
widow and kids what you guys had been up to.
I once had a crank break. In flight. There'd been a
propstrike sometime in the distant past (old engine) and the crack that
resulted finally made itself known. Same sort of engine as in your
friend's old Cub. The crank tends to crack between the #1 and #2
throws. I have a picture of the front end of an O-520 crank that had
been propstruck. Came right out of the engine some time after the
strike.
These days most insurance companies, engine manufacturers and
even some governments want the engine torn down after a propstrike due
to the high incidence of engine failure following such an event. I just
heard the other day of an engine that failed 100 hours after a strike,
and after the gyppo shop missed the crack in the crank and put the
engine back together.
During a propstrike, some Lycomings are known to spit loose the
camshaft drive gear retaining bolt in the back of the crank, eventually
letting the gear get away. An engine doesn't run too well without the
cam turning. See:

http://www.airweb.faa.gov/Regulatory...5?OpenDocument

Some shops find bent or cracked con rods, pistons, cranks and/or cases.
The shock of a prop striking something firm is transmitted directly to
the engine, unlike an automobile that has tires and a drivetrain to
twist and absorb it.

Dan