On pre-flight inspections

A few examples of what I've seen so far:


-) two springs missing that should have held exhaust pipes together.
instructor judged we could fly, though
-) fatigue cracks in a bracket that hold the oil cooler.
instructor judged we could fly, though
-) oil cooler still partially covered for the winter cold on a sunny
day
in May. instructor judged we could fly, though



Badly frayed cable on the horizontal stabilizer. AI caught it while
fueling
the aircraft. Showed it to the pilot who decided it would make back
home,
about 30 miles. AI actually begged his pax to stay behind. At about
200' on
take off the cable failed. Aircraft did a complete loop impacting the
ground
at about a 60 degree angle. Nothing left of the aircraft more than
knee
high. Engine buried about 2'. Pilot died instantly, but the pax with
all
broken bones, struggled for help for almost 5 minutes before expiring.



For a friend here.... he passed on 3 spinner cracks on a rental 172.

One crack was 1 1/2 in long.

They (others) continued to fly the aircraft for another week before
the spinner was removed.


All of these point out the old adage that incompetence is unaware
of itself. In the first cases, the instructor "judged we could fly."
Was the instructor a mechanic, too, or maybe en engineer, to make the
determination that broken or missing parts didn't affect the safety of
the aircraft? Designers and manufacturers don't typically spend money
on stuff that isn't necessary, and as far as cracks go, they don't
usually progress in a linear fashion. They can show up, travel slowly,
then the part can fail all at once as the metal ahead of the crack
reaches its fatigue point from the work-hardening that results when a
crack allows too much flexing. A cracked spinner can kill, and has
done so in the past. They've been known to come through the
windshield. Frayed cables might be ok for a while or might not, as the
instance given clearly demonstrates. Would the pilot of that airplane
have suspended himself thousands of feet above the earth using a
frayed cable? Probably not, be he did what amounted to the same thing.

If we're going to just say "it'll be OK," why bother with the
preflight in the first place?

There are the Five Hazardous Attitudes: Anti-Authority, Resignation,
Invulnerability, Macho, and Impulsivity. Under which one does the
"it'll be OK" fit? And if the law requires that the airplane be
airworthy before flight but we fly it with obvious defects anyway,
where does that fit?


See this:

http://www.pilotoutlook.com/instrume..._and_antidotes

I'll get flamed, for sure, but then you guys can place the flamer
somewhere in the Hazardous Attitude scale.


Dan

wrote in message
...
A few examples of what I've seen so far:
-----------examples snipped for brevity----------

All of these point out the old adage that incompetence is unaware
of itself. In the first cases, the instructor "judged we could fly."
Was the instructor a mechanic, too, or maybe en engineer, to make the
determination that broken or missing parts didn't affect the safety of
the aircraft? Designers and manufacturers don't typically spend money
on stuff that isn't necessary, and as far as cracks go, they don't
usually progress in a linear fashion. They can show up, travel slowly,
then the part can fail all at once as the metal ahead of the crack
reaches its fatigue point from the work-hardening that results when a
crack allows too much flexing. A cracked spinner can kill, and has
done so in the past. They've been known to come through the
windshield. Frayed cables might be ok for a while or might not, as the
instance given clearly demonstrates. Would the pilot of that airplane
have suspended himself thousands of feet above the earth using a
frayed cable? Probably not, be he did what amounted to the same thing.

-----------more snipped----------
Dan

Back when there was a coffee shop, that had become a major hang-out for both
pilots and mechanics at my local airport, I once deferred a question to a
flight instructor who I knew to also be a certified A&E. The questioned was
a student pilot and I knew the correct answer; but really thought that it
should come from someone properly certified--and was utterly astounded by
the avalanche of poppycock that issued forth. I was so doumfounded that I
still can not recall the original question--half a dozen years later.

So, while I completely agree with your basic premise, I must also suggest
that any trust the general knowledge and good sense of a mechanic or
engineer should be evaluated as part of the decision whether to accept his
opinion or the products of his work!

I do know several mechanics who are darned good engineers, even though the
don't have engineering degrees, and also a couple of automotive mechanics
whose opinions I would gladly trust with regard to aircraft; but they are
not all created equal.

Peter