Watch Your Language!
By Mike Busch A&P/IA
[email protected]
When requesting maintenance, the words you use can be very important.
The voice on the phone identified himself as a Cessna 182 owner—let’s call him Jim—who said he
was considering overhauling his O-470-R engine and could use some advice. I asked Jim why he was
considering overhauling his engine, thinking maybe it was approaching TBO and hoping to convince
him this wasn’t a valid reason to tear down a perfectly healthy engine. As it turned out, this engine
wasn’t yet close to TBO.
Jim said his A&P recently pulled a cylinder because it had a leaking exhaust valve. With the jug
removed, the mechanic discovered a badly worn cam lobe and showed it to Jim, explaining that the
engine would need to be removed from the airplane and have its crankcase split in order to replace
the damaged cam. The mechanic offered to do the work himself in-house (rather than send the engine
out), and estimated the engine repair would come to roughly $10,000, including parts and labor. Jim
agreed and authorized the mechanic to proceed.
In a follow-up conversation, Jim asked his A&P whether it might make sense to overhaul the engine,
given that it was already going to be opened up for a cam transplant. The mechanic replied that he’d
be glad to do a full overhaul on the engine, but that it would be a lot more expensive (by at least a
factor of three).
Engine overhaul
Jim wasn’t expecting that, and inquired why overhauling the engine would be so expensive. The
mechanic pulled out a well-worn copy of Continental service bulletin SB97-6B titled “Mandatory
Replacement Parts” and showed Jim all the parts that would need to be replaced at overhaul. These
included, among other things, a pair of new gears (crankshaft and camshaft) that alone would add
$5,000 to the tab. There were 24 additional categories of parts that must be replaced with new ones at
overhaul. All the engine accessories—starter motor, starter adapter, alternator, magnetos, carburetor—
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Cessna Pilots Association -January 2016