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Old November 3rd 04, 08:09 PM
Bill Daniels
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"Wolfgang" wrote in message
om...
Is anyone aware of statistical or other data that would indicate what
percentage of engines make it well beyond the factory specified TBO,
and how much longer they can be flown safely? I worry about sudden
engine failure due to metal fatigue.

Many of the small Lyc. engines have a TBO of around 2,000 hours. My
O-320-D3G (TBO 2,000hrs) has now 2,200 hrs since new, it's never been
opened for any reason. Of the above time, 1,100 hrs have been flown in
my RV-6.

I change oil (15W50) and full-flow filter every 50 hrs, cut-open the
filter for inspection, and have the oil analyzed. The compression is
still in the mid-70s.

I plan to continue flying until any of oil analysis/compression/oil
consumption would indicate a noticeable departure from their historic
values.
But the one other thing I worry about is the matter of metal fatigue,
which would not be indicated by any of the factors that I am
observing, but which could lead to engine stoppage.
If you have any data to support using these engines past their TBO it
would be much appreciated.


IMHO, piston engines will most often fail gracefully in that they give good
indications of ill health well before outright failure. No guarantees, of
course. But, it's pretty hard to find a generally smooth running engine with
low oil consumption and good compression that has failed catastrophically.

The above does not extend to accessories like magnetos and fuel systems
which do fail suddenly and can result in an engine stoppage. It also
assumes that you know the history of this particular engine and that it has
enjoyed excellent maintenance without suffering any trauma like a prop
strike.