On Wednesday, March 5, 2014 8:01:30 PM UTC-7, BobW wrote:
On 3/5/2014 2:53 PM, John Carlyle wrote:

Agree with your three points of how pilots get into trouble. I also agree

that training is important, and that it's never a bad idea to take a ride

with an instructor.



I'm not sure I buy your theory of an optical illusion in your peripheral

vision causing your central vision and inner ear to start giving you bad

data, though. It takes time (probably a minute) without good visual cues

for your inner ear to start disconnecting from reality.



Apologies for the thread drift, but my experience strongly suggests the

"probably a minute" for inner ear to disconnect from reality is "probably

(way?) too long."



I once inadvertently entered an utterly benign (no overdevelopment anywhere

that day) thermal cloud by horribly misjudging the base in conjunction with a

honking climb rate. In the dry intermountain west, racing another guy half a

mile away over the plains of eastern Colorado, it went from CAVU VFR to

solidly-opaque IFR more or less instantly. Flying in a

large-deflection-landing-flap-equipped sailplane (no spoilers) thousands of

feet agl in the middle of nowhere, I wasn't worried about pulling my wings

off, but I *was* distinctly irked at my poor judgment, mostly because if I

didn't fly out the side of the cloud quickly, my buddy would gain considerably

on me. (Standard glider pilot priorities!)



I'd at least had the sense to establish my climb near the far edge of the

miles-long cloud, had a long-established bank angle/turn-rate, and figured I'd

a good chance of rolling out on a heading to have me clear of the cloud within

no more than 5-10 seconds at the most. Without moving my head, once inside the

solidly opaque cloud, and not touching the controls until estimating it was

time to roll out, I did so, timing/estimating wings level, and waited. The

only thing that happened "instantly" was violent vertigo, and within 15

seconds several things were clear: 1) I wasn't going to exit the side of the

cloud; 2) I'd stalled at least once (at which point I pulled on full flaps);

and 3) it was anyone's guess how long I'd be in the cloud and what my flight

path might be while there. Ultimately, I lost 700 feet from my max altitude

before exiting the thing, out the bottom, steeply banked the opposite

direction from that entered, and never knowingly having commanded bank after

the attempt to unbank to level. My buddy was nowhere in sight, of course.



Point being, don't bet your life on having much time IFR before losing

complete control of your glider. Secondary point being (of course!) don't go

IFR at all, but if you DO go IFR be prepared to lose your wings and maybe your

life unless your glider has gobs of disposable drag...as has had every

landing-flap-equipped sailplane I've flown. Wonderful things, large deflection

flaps!



Bob - occasionally bozo - W.

The best data says a pilot will lose control of the aircraft in mere seconds in a cloud if not trained and equipped for instrument flight.

The inner ear serves no useful purpose in aviators. It only serves to induce one of the many aviation specific illusions and/or vertigo. We didn't evolve to fly so we must learn to deal with our limitations. The best pilots learn to ignore vestibular sensations and rely on sight - viewing instruments or outside cues. This lesson is best learned under a hood with a CFII in the right seat.