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RE: [RC] Pilot Error - David LeBlanc


Kat said:

That's what they always chalk them up to, unless there's a clear 
mechanical failure.

I rest my case.  In the absence of a clear mechanical 
failure, the NTSB understands that all accidents are caused 
by pilot error.

No, you're mis-reading what I said. The NTSB puts the blame on pilot error
when they don't know what caused the accident. Logic goes like this - is
there a provable mechanical failure? If not, did the pilot provably screw
up? The answer to the last question doesn't matter - it's chalked up to
pilot error. There was an airliner a few years back where the _tail_ fell
off, and it was chalked up to pilot error, not that the engineers didn't
build a plane correctly. If the engine falls off, or explodes, or the pilot
does something completely wrong, like takes off on the wrong runway, then
they can clearly assign blame - but in the absence of a clear fault, it's
'pilot error'. If the pilot had done something really bad, the report would
likely have been more clear about the exact error so other pilots could
learn from the mistake.

For example, my father used to fly jet trainers in the late 50's. The
aircraft was built such that you couldn't see anything when you were coming
in for a landing. He saw a number of people die from 'pilot error', when the
real error was the idiot who put student pilots in a plane designed to
amplify mistakes.

I'm somewhat doubtful that another 150# or so tipped the 
aircraft over 
the edge, especially in that manner.

It is a brave man indeed who is willing to guess at a woman's 
weight...and in public!  

Fools rush in where angels fear to tread 8-)

However (despite the joke between my vet and me, which David 
apparently didn't get) I also doubt that it was the extra 
"150# or so" that tipped the aircraft over the edge, and that 
it would have had trouble taking off in those conditions 
anyway.  The conditions for landing safely and the conditions 
for taking off safely are not necessarily the same 
conditions.  The fact that the helicopter successfully took 
off from a helipad in St. George where the flight originated 
(open parking lot, altitude 2,500') doesn't count for 
determining whether it could safely take off from a small 
clearing in the trees on the Kaibab Plateau.

It's all weight vs. lift. If the aircraft had enough lift to fly higher than
where it picked you up, it had enough lift to take off. That aircraft is
designed to hover fully loaded at around 5000 feet higher than you were.
You're right that it taking off from 2500' lower doesn't tell you anything,
but if the pilot could fly even a thousand feet above where it picked you
up, there was enough lift. The small clearing may have been a problem, but
that doesn't account for why the tail rotor wasn't doing its job. It clearly
did its job at a higher altitude. Another factor is that it would be a
design failure for the tail rotor to be the first thing to fail at higher
altitudes - you'd have helicopters falling out of the sky all over the place
- they'd get too high, start spinning, and it would get ugly from there.
We're supposed to build most aircraft to return to a stable attitude when
left alone.

Helicopters are just basically dangerous, even under the best of 
conditions.

Yep, which is why you won't catch ME flying in one again 
absence a life threatening situation.  Give me a fixed wing 
aircraft any day, THOSE things are actually designed to fly.

I would personally tend to avoid them. Funny thing is that I've been more
nervous about flying since I learned how to build them than I was before.
The one time you're safer in a helicopter is exactly the same type of crash
you experienced - that and engine failure above about a few hundred feet -
you can trade off potential energy for lift, and I've seen one land with the
engine off as softly as it flew in.

The thing about helicopters that really amazed me is that the rotors change
pitch through their rotation. Fixed wing aircraft have two vibrational
modes, helicopters have three. Those blades wobble around in all sorts of
ways, and that vibration plays all sorts of tricks on the aerodynamics that
results.

This doesn't change the fact that the cause of the accident 
at all was probably because the pilot chose to fly that 
helicopter in conditions that were too close to the edge of 
its mechanical capabilities.

I don't think they explained why that tail rotor did what it did that day.
High altitude was surely a contributing factor, but the ceiling for that
aircraft fully loaded is about 5000 ft in effective altitude higher than you
were, accounting for temperature. He should have been able to fly that high,
according to the manufacturer specs. I'm also doubtful that the air
ambulance company would have been certified if the pilot and the two
attendants, along with the equipment, had put the aircraft that close to
it's rated capability. If it was certified for that use in that
configuration, then we have a failure on the part of the FAA.

Glad you made it - not many people live through an aircraft crash. Also glad
you weren't hurt worse - the time my horse and I wrecked, I lost about 3
hours. Drove everyone around me nuts - every 2 minutes, "What happened?"
Then if they wouldn't tell me, I was mad at them for about 2 minutes...





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Replies
[RC] Pilot Error, k s swigart