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ACRO E-mail Archive Thread: Mechanics / Technicians (was RE:Engine Problem ...


Thread: Mechanics / Technicians (was RE:Engine Problem ...

Message: Mechanics / Technicians (was RE:Engine Problems Solved

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From: "John Collier" <collier at>

Date: Tue, 13 Feb 1996 14:40:04 UTC


This topic should really generate some lively discussions. I can see
both (several score?) sides beginning their warm ups now. But seriously,
mechanical skills are acquired through experience. There are some really
good schools that teach a lot of the mechanics but like schools of all
types, the result of graduation is really just a license to go learn.

When I was in the service, we had a big rash of "surging props, unable to
maintain sync" write-ups. We followed all the service bulletins, even had
the manufacturing reps from P&W, Beech, and Woodard work on the problem.
We changed governors and props until everyone was really getting frustrated.
Late one night,as I was changing yet another governor, I happened to notice
that the gasket we were using was "new". The screen, instead of being small
mesh and curved in a semi-circular arc was now a punched metal screen with a
square cross section. When I placed the gasket over the pad, the screen
essentially blocked the oil holes, reducing the cross sectional area by more
than half. The "new" screen had been approved as a substitute through all of
the formal channels of all the manufacturers yet it was the cause of the
problem. We went back to the old style screen and the problems were solved.
You, as the taxpayers spent well over $0.5 million solving this problem.

The moral of this story is that as mechanics, we attempted to solve the 
problem by looking at the most likely causes first. In the military, the
most likely causes are documented (sometimes) in the manuals. When you exhaust
all the likely causes, you move to the less common causes. 

Now as for posting success and failure stories, I'd suggest that we all focus
on the positive ones. In reading the rec.aviation.* groups this past year, 
I have seen great numbers of "they ripped me off man..." stories that have
really been situations like I described above. It's tough to be on the
discovery end of a difficult problem but it happens. 


© Dr. Günther Eichhorn
Email Guenther Eichhorn