"Jim Macklin" wrote in message
(c) The aircraft does not have to be flown as required by
paragraph (b) of this section if, prior to flight, ground
tests, inspection, or both show conclusively that the
maintenance, preventive maintenance, rebuilding, or
alteration has not appreciably changed the flight
characteristics or substantially affected the flight
operation of the aircraft.

The last chapter of the Lycoming opposed engine overhaul manual specifies
that the rebuilt engine must be run in a calibrated test cell. That shows
conclusively that the flight characteristics won't be substantially
affected. Therefore, who needs the pilot?

Incidentally, and don't ask me how I know, does everyone here with an
overhauled cetificated engine have a record of a test cell run in the
engine's overhaul records?

Now then, I seem to remember something about integral superchargered engines
needing to be overhauled by an approved facility. When I ran R-985s, we had
to send them out as we weren't allowed to overhaul them ourselves.

D.