Downdraft at 12,000 feet

N2310D schrieb:

Glider pilots use rotors routinely as an elevator to the wave. At some

No, gliders may transit the rotor but they sure as hell don't like

You're talking to a glider pilot. And the question was not whether we
like it, but wheter the wings stay attached.

Personally, I like the wild ride of a rotor. But I agree that I may be
somewhat untypical.

Stefan

On Thu, 04 Jan 2007 11:27:52 -0700, Newps wrote:



Danny Deger wrote:


No certificated GA plane is unstable in roll.

Go rent one and see for yourself.

I own one.


If you put it in a 30 degree bank
and let go of the stick, the roll will increase until you are in a death
spiral.


Yours was rigged wrong. When put in a coordinated bank it will stay in
that bank.

One of you is talking about a *stabilized* turn, the other it talking
about rolling into a 30 degree bank They are two different animals.
The Deb and Bo will keep right on going if you just roll into a 30
degree bank and let go. They will both happily fly a stabilized 30 or
45 degree banked turn hands off.

Roll mine into a 45 degree bank and dowwwwwnnnn we go. Roll into a 45
degree stabilized turn and trim and I know it'll do a 720 with so
little altitude variation you can barely see it.




That is why so many Bonanzas end up in one compared with other
airplanes. As far as I know, all Cessnas are stable in roll, i.e. without
pilot intervention they roll back to wings level.

I had a 182 for seven years and they will act the same as my Bonanza.
Put them in a coordinated bank and it will stay there.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Stefan wrote :
I spent a good 5 min. with very little control over my plane.

You stayed 5 minutes in the rotor and didn't even think of doing a 90
degrees turn and leave it?

I wasn't kidding when I said I had very little control over the
plane. The first few minutes I concentrated on keeping the shiny side
of the plane pointed up. I was eventually able to generally point the
plane 90 degrees to the left and fly out, but even that took awhile.

John Galban=====N4BQ (PA28-180)


--
JGalban
Posted at www.flight.org

On Tue, 2 Jan 2007 12:09:26 -0800, Robert M. Gary wrote
(in article om):


James Robinson wrote:
Pilot reported heavy downdraft over Lancaster, CA, resulting in crash.

http://www.orovillemr.com/news/chico/ci_4917367

Can somebody explain what he did right/wrong?

That's happened to me out there too. I reported to ATC that I couldn't
maintain atltitude and got pulled down into the clouds. I picked up a
bit of ice and went below the MEA. Luckily I had a terrain GPS on board
and could stay between the mountains.

Yeah, I have had that happen to me out there, too, but no ice. It can get
especially bad at night. I remember one night hearing a pilot in a Bonanza
that was very frightened by it.

On Tue, 2 Jan 2007 10:58:30 -0800, James Robinson wrote
(in article ):

Pilot reported heavy downdraft over Lancaster, CA, resulting in crash.

http://www.orovillemr.com/news/chico/ci_4917367

Can somebody explain what he did right/wrong?

I doubt very much that he was in a death spiral. Stiff downdrafts are very
common in the area. You can't climb out of them. You either turn away from
the mountain or you start picking up speed and get out of there (you get to
ride the elevator up on the other side of the mountain, so a little descent
to pick up speed doesn't cost you nearly as much as the amount you will
descend if you stay there).

I remember one night another Bonanza got into trouble with a downdraft near
there. The pilot was pretty panicky on the radio. He got below minimum
terrain clearance and was trying to circle (!) to climb up again. Fortunately
he somehow flew out of it, probably learning the wrong lesson in the process.

On Thu, 4 Jan 2007 09:20:32 -0800, wrote
(in article ):

Morgans wrote:

"JGalban" wrote

Which is exactly where you'd expect to find a rotor from the wave
spilling over the mountain. Flying into a rotor is more than just your
average downdraft. If it's strong, you can expect serious pitch and
bank excursions. Simply put, the plane can easily be out of control.
Combine that with IMC and loss of control would probably not be far
behind.

From what I have read, entering a real rotor, one would be lucky to be spat
out with the wings still attached to the plane.

Loss of control? Certainly.

Loss of plane? Perhaps.

Thoughts? Some out here can discuss rotors with authority, I'm sure.

Jer ? ? ?

There are rotors, then there are ROTORS!

Hmmm. I suppose it was a ROTOR (as opposed to a mere rotor) that tore the
tail off a B-52 near the Sangre de Cristo mountains in Colorado in 1964. IIRC
the crew managed to land the plane anyway.

In article m,
C J Campbell wrote:

On Thu, 4 Jan 2007 09:20:32 -0800, wrote
(in article ):

Morgans wrote:

"JGalban" wrote

Which is exactly where you'd expect to find a rotor from the wave
spilling over the mountain. Flying into a rotor is more than just your
average downdraft. If it's strong, you can expect serious pitch and
bank excursions. Simply put, the plane can easily be out of control.
Combine that with IMC and loss of control would probably not be far
behind.

From what I have read, entering a real rotor, one would be lucky to be
spat
out with the wings still attached to the plane.

Loss of control? Certainly.

Loss of plane? Perhaps.

Thoughts? Some out here can discuss rotors with authority, I'm sure.

Mountain waves can generate tremendous lift (on the smooth side) and
catastrophic turbulence on the rotor side.

Back in the 1950s, Paul Bickle, director of NASA flight research at
Edwards AFB, had some Pratt-Reed sailplanes instrumented to research the
Sierra Wave. These were WW-II military training gliders, good for +9g,
-4g. They lost one when it came apart in the rotor; fortunately, the
crew bailed out and survived.

Legend has it that Tony LeVier soared the F-104 in the Sierra Wave. He
shut down the engine and returned to base 2 hours after expected fuel
depletion.

wrote:

Morgans wrote:

"JGalban" wrote

Which is exactly where you'd expect to find a rotor from the wave
spilling over the mountain. Flying into a rotor is more than just
your average downdraft. If it's strong, you can expect serious
pitch and bank excursions. Simply put, the plane can easily be
out of control. Combine that with IMC and loss of control would
probably not be far behind.

From what I have read, entering a real rotor, one would be lucky to
be spat out with the wings still attached to the plane.

Loss of control? Certainly.

Loss of plane? Perhaps.

Thoughts? Some out here can discuss rotors with authority, I'm sure.

Jer ? ? ?

There are rotors, then there are ROTORS!

The power of rotors was demonstrated by the loss of a BOAC 707 in Japan
in 1966. It was making a sightseeing detour because of exceptionally
clear weather close to Mt Fuji, and broke apart in flight.

The aircraft appears to have flown into a rotor downwind of Mt. Fuji, and
first lost the vertical stabilizer, followed by the horizontal
stabilizers, the engines, and the extreme end of the right wing. What
was left descended in a flat spin.

The amazing part is that Mt.Fuji is about 12,400 feet, and the aircraft
started breaking apart at about 16,500 feet altitude, almost 10 nmiles
downwind of the summit. Who would generally expect a rotor that high
above the mountain?

Winds were measured at 60 to 70 kts by the weather station on the summit
of the mountain. There were apparently no lenticular or rotor clouds in
the vicinity of the mountain to give a visual clue of the winds power.
Other aircraft reported severe turbulence up to 27 nm from the mountain.

The pilot of a Navy A4 sent to look for the aircraft reported that when
he was downwind from the mountain, he encountered turbulance that tore
off his oxygen mask, caused his head to bang back and forth in the
canopy, his instruments to be unreadable, and the controls almost
useless. He managed to climb out, and when the G meter was downloaded,
it read +9 and -4 Gs.

It certainly makes one respect the potential power of a mountain wave.

Once I flew past Mt Shasta in Northern CA on my way to Oregon - with a
healthy tailwind. I had to cross over the lee side of the mountain to
get where I was going - and delayed doing so for probably 20 miles to
avoid possible turbulence. I got a good bounce anyway. There was no
visual cue to indicate what was happening.

David Johnson