av8tr wrote:
My partner and I just purchased a Piper Warrior from California. All
the compressions on the engine are 72 or better. We test flew for about
two hours and found no problems. Just recently she was taken in for the
Canadian inspection. The AME in Brampton told us that the compressions
were good but one cylinder was cracked. What I would like to know is
how can you have good compressions with a cracked cylinder. Also how
can you determine that a cylinder is cracked without dismantling the
engine. The aircraft is a PA28-151, with a 0-320. If anyone can clairfy
this issue I would really appreciate it. Can you fly the plane this way
or is it dangerous.

Thanx Jurgen..

During an import inspection the mechanic may have seen a bit of
exhaust staining on the cylinder head. He would look for a crack during
the compression test using a soap and water mix on the head and upper
cylinder. Lycoming cylinders can crack between a sparkplug hole and the
exhaust port, and it might not leak enough to show up on the
compression tester but will sure make some bubbles in the soap. You
can't just let it go, either.
When we do the Canadian AD that applies to all exhaust systems
that take cabin heat from the exhaust system (CF90-03R2), we use the
soap and water on all the exhaust components and frequently find small
cracks before they get serious (and expensive).
Be thankful for a mechanic who keeps you safe. There are a few
who will try to rip you off, but most of the rest just don't want to
get blamed for overlooking or ignoring something that caused an
accident.

Dan