Spatial desorientation (vertigo)

[routechecker]

Hi,

On a recent chat with friends a question popped up.
It is well known that the life expectancy of a untrained VFR pilot in IMC conditions, is rather short.
My question; do IFR rated pilots with, let's say, a couple of thousand of hours under the belt still get that "sinking" feeling and have to force themselfs to trust the T? Does the desorientation feeling go away with time/experience?

Thank you in advance for your replies.

[OBK!]

(not IFR pilot!)

It is well known that the life expectancy of a untrained VFR pilot in IMC conditions, is rather short.

An untrained VFR pilot's life expectancy in VFR would be rather short...don't you think? :}

Does the desorientation feeling go away with time/experience?

I doubt the disorientation feeling will ever go 'away' because, think about it, that's like becoming immune to motion...I don't think anyone is?

do IFR rated pilots with, let's say, a couple of thousand of hours under the belt still get that "sinking" feeling and have to force themselfs to trust the T?

I should hope all pilots trust their 'T' without being force, when in IMC...What else you going to reference your heading to? The fluffy clouds? :ooh:

[Sensible]

Quite simple really, don't look outside and believe ONLY your instruments and then everything is ok. I don't yet have anything like a coupleof thousand hours either!

[Lu Zuckerman]

A US Army H-34 pilot got caught in a fog bank (low clouds) in a canyon. He brought his helicopter to a hover indicated by zero airspeed and zero rate of climb. The characteristics of this helicopter in a hover are to hang tail down by three degrees and seven degrees to the left. His flight instruments indicated that he was in a climb and banking to the left. His air speed indicated zero and his rate of climb indicated zero rate of climb. He had lost all spatial orientation and eventually crashed killing himself, his co pilot and his crewman. Would you have done it differently?

The instruments indicate fuselage attitude.

:sad:

[Evil J]

I'm no Helo pilot, but wouldn't he have been better stopping, and pulling the collective up to his armpit to get away frrom the hard stuff? ie airspeed zero, rate of climb as much as possible, keep the disc level...

Just a thought

[Whirlybird]

Lu,

Yes, I would have done it differently. Without IFR training for that helicopter, I would have made damn certain I wasn't there. And with that training, and the practice required to keep up a scan, I would have understood what my instruments were telling me.

On my recent helicopter FI course, I asked if the disorientation decreased with time. In an R22 on instruments, I feel like I'm in a steep right turn when I'm straight and level; I trust my instruments and ignore it, but sometimes it makes me quite nauseous. My instructor said "the leans" don't go away, but do tend to reduce if you do a lot of instrument flying...and he's done a lot.

[Lu Zuckerman]

The H-34 pilot was the lead in a trailing formation of seven or eight helicopters. When he realized what was happening he ordered the other helicopters to come to a hover and do a 180. Those pilots had visual contact with the canyon walls and the canyon floor. They got out. Pulling collective up to his armpits might have worked but what if he translated sideways and hit the canyon wall. It was assumed in the accident investigation that the pilot in losing spatial orientation suffered from vertigo and any action would result in disaster.

Shortly thereafter the Army installed ASE on their H-34s and the ASE when rigged was nulled out to reflect a level condition when the helicopter was hanging tail down and to the left so even if the instruments indicated a climb to the left the ASE would indicate level flight. This may or may not have helped the subject pilot.

:sad:

[Whirlybird]

Lu,
That sounds like a sensible decision. Hard to believe he didn't see the stuff coming, but that's easy to say, sitting here. If it was that sudden, and he had to let people know, come to a hover in IMC, turn with no leeway for error, AND interpret what the instruments meant....yikes!!!!!! :eek: :eek: :eek:

[eyeinthesky]

To answer the original question: No the 'leans' never go away. I do a lot of (fixed wing) IMC flying without an autopilot and regularly have to combat the leans. The ONLY way out is to concentrate on the 'T' and fly according to that. They do then sort themselves out.

[Thrifty van Rental]

Whilst anybody can suffer from an attack of the leans at any time, it helps if you know that there are circonstances that are more likely to give rise to them. Taking off into a low overcast is one such example.

They never go away completely, as others have written, but they can be managed and controlled with a little experience.

TvR

[Lu Zuckerman]

I can really understand how spatial disorientation can lead to vertigo with the resultant effects. I was returning from a business trip to San Diego en route to the Hughes airport in Culver City. I was sitting in the right hand seat of a Beech King Air and we were flying between two very heavy cloud layers. One aircraft to our right was letting down to the Hawthorn Airport and another was climbing out from that same airport. Both aircraft were inclined in relation to the horizon (which was not visible) and I tried to reconcile their attitude to our attitude and it caused some degree of confusion that is until I looked at the instruments which indicated we were level in relation to the horizon and the other two aircraft were not.

:uhoh:

[kabz]

On one of my practice ILS', I experienced SEVERE disorientation on the missed. I could see a couple of spits of land with lights on them, jutting out into the Gulf. This gave me enough to make me feel I was far too noseup, and I just wanted to dive.

It pretty much can take everything you have to trust the instruments, and being tired would only make it harder.

It's hard to imagine unless you have had it bad like that. Mild leans was pretty normal for me, especially as my training included some late steepish turns onto localisers.

[foghorn]

I don't have many thousands of hours, but like eyeinthesky I do fly manual IFR in light aircraft fairly regularly. The answer is that with experience and currency the leans do not go away, you just get better at ignoring them and focussing on what the instruments are telling you.

[crispy banana]

As most of the people have said,they never really go away,but I have found that the worse time is just after entering IMC,especially if being vectored and climbing :yuk: :ugh:

I had a bad expierence a few months ago with that->was vectored left and right a few times within about 20-30 seconds while climbing, just after entering IMC and I got a bad case of the leans :\ :\

I just kept concentrating on the T and within a minute or so it had passed :)

Just keep a cool head and trust the instruments (and your vac system :ooh: :ooh: ) and it usually passes!!

C