Question regarding to a recent R22 crash with failure autorotation

[jbskies]

Hi

I am a fix-wing guy. I read about a recent R22 crash in AZ.
http://www.ntsb.gov/NTSB/brief.asp?ev_id=20060228X00255&key=1

I have question that was it the limitation of the R22 caused the
accident, or the pilot failed to, or made serious mistake that causes
the blade stop?

I read about a very good discussion at this group (posted in 2004)
regarding to R22 autorotation.
http://groups.google.com/group/rec.aviation.rotorcraft/browse_frm/thread/fa94d3decfeff9af/54e010bbfd0d2fcf?lnk=st&q=autorotation+blade&rnum=3&hl=en#54e010bbfd0d2fcf

However, I still don't understand much because I am a fix-wing pilot.
Can anyone point me out why the blade would stop? Is there any online
introductory reading regarding to autorotation?

This kind of blade-stopping-accidents scares me to even try a
helicopter flying. I hope any of you could give me explanations that
help me understand helicopter more.

Thanks in advance.

jpskies

[jbskies]

> According to Robinson, you
>have about 1.1 seconds to lower the collective and enter the
>autorotation once the engine dies.

Thanks for the reply. It is very helpful. But I am astounded that the
emergency handling window is only 1.1 second. According to AOPA, pilot
usually takes 3 to 4 seconds to "register" the emergency before s/he
react. 1.1 seconds is out of AOPA's range but it is on the edge of my
standard. I had chance to let my Piper running out of one tank. That
probably took me 1 second to switch tank. The second day, engine
stopped again inexpertly in the cruise because there was air bubble
went into the fuel line, that took me about 1 second to turn on the
fuel pump. But it does on edge if R22 is only 1.1 second. You have
absolutely no window for the mistake, second guess or register the
problem slowly.

[Don W]

jbskies wrote:

>>According to Robinson, you
>>have about 1.1 seconds to lower the collective and enter the
>>autorotation once the engine dies.
>
>
> Thanks for the reply. It is very helpful. But I am astounded that the
> emergency handling window is only 1.1 second. According to AOPA, pilot
> usually takes 3 to 4 seconds to "register" the emergency before s/he
> react. 1.1 seconds is out of AOPA's range but it is on the edge of my
> standard. I had chance to let my Piper running out of one tank. That
> probably took me 1 second to switch tank. The second day, engine
> stopped again inexpertly in the cruise because there was air bubble
> went into the fuel line, that took me about 1 second to turn on the
> fuel pump. But it does on edge if R22 is only 1.1 second. You have
> absolutely no window for the mistake, second guess or register the
> problem slowly.

That is why there is a rotor low RPM warning light and horn just like
the stall light and horn on an airplane. When that light comes on you
don't think, you just push down the collective, because if you don't
you're going to hit the ground really hard in a little bit.

Unlike and airplane which stalls, and then tends to recover as long
as it doesn't enter a spin, low rotor RPM in a helicopter results
in a rotor blade stall, which then results in a "blowback" which
results in the rotor blade contacting the tail of the airframe,
which results in a short, really scary ride to the ground.

I've only got a few hours in Robinsons, but they were all flown in
Arizona, and I just checked my logbook to see if I might have actually
flown the ship that crashed (I didn't). I hope the instructor was
not someone I know.

I'm still trying to figure out what probably happened from the
NTSB report. It is hard to belive that a CFI would let a simple
auto get away from him. Something else must have happened beyond
simply engine failure.

DAMN it!

Don W.

[jbskies]

>Was the pax someone who got an intro flight from his girlfriend? I
>can't even imagine how she's feeling...

It was a she. This was her first helicopter flight. She was a flight
attendant.

Crash story:
http://www.eastvalleytribune.com/index.php?sty=59731

Pilot and pax:
http://www.azcentral.com/arizonarepublic/tempe/articles/0224sr-crash0224Z10.html

RIP

[jbskies]

Oppse, the crash story was groofed up.. here is a new link:

http://www.azcentral.com/arizonarepublic/local/articles/0223crash0223.html

It was a tragedy. I feel sad for her 14-year old daughter.