Usually, we look for something greater than 60/80 when doing compression checks on Lycoming engines. A reading such as this one (36/80) really warrants further investigation. In this case, a borescope picture showed an exhaust valve that was in danger of imminently failing. It’s easy to find the air leakage when doing a compression test by placing your ear at either the oil filler tube (usually indicates leakage by the rings) or at the exhaust stack (will indicate exhaust valve leakage) or at the air intake (which will indicate a leaking intake valve).
In Case You Missed It
Flight Testing: Static System Error, Theory and Practice
Flight testing requires precise airspeed calibration and measurement. A less-than-optimal pitot-static system can compromise those numbers. Heres how to troubleshoot the problem.
The Dawn Patrol
Dick Starks - 0
The Dawn Patrol crew managed to stay out of trouble (mostly) on their visit to the Gathering of Eagles in Gardner, Kansas.
Second Chance Six
Tenley Ong - 1
Part 5: Uncovering the history of N2165U and doing lots of sanding.