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At 05:18 PM 12/9/2005, [EMAIL PROTECTED] wrote:
1. The fact that a part has a yellow tag and is legal doesn't mean
anything except that it has a yellow tag and is legal.
A "yellow tag" really has no meaning from a regulatory
standpoint. It certainly does not guaranty the part is "legal". The
term "yellow tag" does not appear anywhere in the FARs. It is
generally accepted that if someone buts a "yellow tag" on a part that
person has determined that it is serviceable, but still there is no
reg to back this up. If you get a yellow tag and it has a repair
station number on it, then what you really have is a maintenance
release that happens to be printed on a yellow tag. This should have
some real meaning, but, as the previous post points out, it's only as
good as the person doing the inspecting, or not doing it, as the case may be.
2. Never make the mistake of assuming that just because a part was
overhauled or reconditioned by a certified shop that the part is
good. It's up to the owner and the installing mechanic to verify
that the part is good. Again, we already knew that. In this case,
both of the defects (the protruding bushings and the narrow rocker
arm) were impossible to notice unless you knew to be looking for it
and checked the part with vernier calipers or a micrometer. My
mechanic and I did look at the rocker arms and inspect them, but you
can't really notice something being a few thousandths out of place
with the naked eye.
No, but the installing A&P should check all applicable parameters in
the course of installation, in this case the side clearance. That
would pick up the undersized part. It may even pick up the
protruding bushing as it would be impossible to move the rocker to
zero clearance on the side it protrudes.
Not to defend anyone, but it is fairly common for the rocker arm
bushings to migrate to the point where they protrude and wear,
resulting in copper in the oil analysis.
John Cooper
Skyport Services
PO Box 249
4996 Delaware Tnpk
Rensselaerville, NY 12147
518 797-3064
Fax 518 797-3865
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