Russian B737 Crash at Kazan.

[mercurydancer]

As SLF I cant really critique your analysis, but judging by two factors, your very sensible, reasoned and logical previous posts, and obvious experience it sounds quite plausible.

I found the video clips really disturbing as I was shocked by the angle in which the aircraft hit the ground. I have studied transport accidents as part of my masters in risk management and investigation, so the combination of errors which led to Kegworth, Potter's Bar, Everglades, Ladbroke Grove disasters are very familiar. The Swiss cheese lined up in a certain way, but the errors were subtle and deceptive. What I struggle with is that an aircraft can impact at such an angle.

[ohnutsiforgot]

Ummm...

"The problem comes when you book with Aeroflot for connecting flights, you may get Donavia or other companies without much information or little opportunity to change flights."

One word. Colgan.

[mary meagher]

Mercury Dancer, the way we teach landings (in gliders) is to aim at the ground and then miss. If you fail to perform correctly the second part of this procedure, the aircraft will then stick in the ground like a dart. This more or less holds true for approach and safe landing in most types.

[Agaricus bisporus]

Jeez! Why do all the theories have to be to most complex and least probable?

Look at the simplest reason for loss of control and you'll "probably" have the "right" answer.

All this about somatogravic xyz or flap fail/fuel imbalance (certain balls) is all very well The most likely cause is quite simply overpitching due to a mishandled g/s and botched recovery, I'd be astonished if it were anything else.

if it looks like a duck, quacks like a duck....

[fireflybob]

if it looks like a duck, quacks like a duck....

ab, with you all the way.

Am surprised nobody's started bleating about Boeing should change the autopilot logic etc etc

[Clandestino]

if it looks like a duck, quacks like a duck....

... then it is someone who has not read MAK's information about FDR readout.

[olasek]

if it looks like a duck, quacks like a duck....

Yeah, but any such "duck" often has a fair amount of pilot's disorientation in it. "Botched" recovery at night with little outside reference is often directly related to inattention to instruments which often has root cause at some sensory illusion. I think this Pilatus' crash may be a highly relevant example regardless if you attach some fancy name to it like somatogravic.

[fireflybob]

So if we regard the somatogravic illusion as a potential "threat" how should this be managed?

[olasek]

So if we regard the somatogravic illusion as a potential "threat" how should this be managed?

This is what they teach during a typical IFR course: do not get yourself into unnecessarily drastic manoeuvres in an IFR environment, don't make too steep turns, control your pitch within limits, trust your instruments, etc. In this example a 25 deg pitch up was completely uncalled for and significantly outside what was required. It was enough for them to follow the FD guidance (assuming of course it was correctly configured).

[freespeed2]

9gmax

Could it be a case of Vestibular/somatogravic illusions? ...Anybody wants to comment?....

We did; in posts #96, 98 & 99.

All this *** about somatogravic xyz or flap fail/fuel imbalance (certain balls) is all very well The most likely cause is quite simply overpitching due to a mishandled g/s and botched recovery, I'd be astonished if it were anything else.

I think you are correct in saying that the overpitching and botched recovery is the direct cause but it oversimplifies the wider cause that needs to be recognized. An aircraft should recover within the available altitude considering that a high power setting was already achieved. The stall would be broken quite quickly. The only reason to continue to pitch forward is because the pilot thought that he was still increasing his pitch. He did not believe his instruments. Look at the report linked in post #96. In the Annex is an excellent explanation of somatographic illusion. The rapid pitch up or the stall did not cause the illusion. It usually begins when an upward pitching motion is abruptly checked around 20-30 degrees nose up, so in this case it began when he tried to recover from the stall. This is what sends the semicircular canals spinning and causes the false pitch up sensation.

It is impossible to demonstrate this effect in a simulator during training due to the lack of 'g' effects. This pilot may not have even been aware of the phenomenon judging by the previous comments about how the training and qualifications are achieved.

[misd-agin]

Quote:
Could it be a case of Vestibular/somatogravic illusions? ...Anybody wants to comment?....
We did; in posts #96, 98 & 99.




....post 39...

[The Ancient Geek]

It is impossible to demonstrate this effect in a simulator during training due to the lack of 'g' effects. This pilot may not have even been aware of the phenomenon judging by the previous comments about how the training and qualifications are achieved.

But easily taught under the hood in a light aircraft.
Which is where, IMHO, all pilots should learn about recovery from unusual attitudes.

A few hours per year in an aerobatic trainer should be part of maintaining currency and is not expensive.

[Dan Winterland]

The somatogravic illusion (SI) cannot be taught in the air. The standard IF syllabus demonstrates the corilis effect and the somatogral illusuion, but the SI cannot be taught in either aircraft or simulators. To induce it, you need a sustained peripd of acceleration and experience shows that if you are expecting it, it's not going to happen to you. It can only be taught in the groundschool phase with advice on how to counter it. Mitigating strategies such as making sure you stay on instruments and don't descend on take off or during a go-around can be introduced in night and IF syllabi, but demonstrating it effectively has so far eluded the flying training systems.

I have been conducting some research into the SI and have come up with some interesting facts.

First, it's nearly impossible to adequately train for in practical terms. This, is mentioned above.

Second, it's been killing people for years and it continues to. I have details of about 200 crashes where the SI is a probable cause of a crash, but there are undoubtedly many more, as the SI is often not understood or identified by accident investigators, and for the sobering statistic that the fatality rate for SI accidents is about 85%. Pilots don't generally live to tell the tale!

Third, many pilots are aware of the illusion, but fail to recognise it when it happens to them. This is because it is a dim and distant memory from their Human Factors and Performance syllabus - if they did it! Don't forget, HPF was only really introduced as a mandatory subject in the early 1990s.


In my opinion, this crash is a classic SI case.

[misd-agin]

A light airplane doesn't have the thrust to weight, speed, and acceleration of a jet aircraft. So it's better than a simulator but the inability to generate the acceleration of an airliner on a G/A makes it a poor comparison.

Worst vertigo was a light weight, night, 757 ferry flight LGA-JFK. Max power for windshear in the area(SOP). LGA 13. Tremendous acceleration. Right turn to 175 immediately after liftoff. In the turn tower changes it to left to 060 and level off at 2000'. In the turn, leveling, power coming back, unloading from high rate of climb ... and we go into the clouds ... and moderate turbulence. Bam! Perfect storm. Vertigo. Big time. SOP is to call it out "I've got vertigo". FO - "I do too." Tough stuff when you're fighting it. Experience and training is key.

[Dan Winterland]

You don't need much acceleration to generate the somatogravic illusion. As it's pure geometry it can be calculated. An acceleration of 30kts over a period of 10 seconds is equivalent to 1.54m/sē, which translates into a perceived pitch up of 9°. As many aircraft climb at a lesser angle than this, the aircraft can conceivably enter a descent if the illusion is not correctly countered.

This means that pilots of low powered GA aircraft are just as susceptable as jet pilots. And the staistice reflect this. Somatogravic illusion accidents either tend to occur during go-arounds for airliners, but GA aricraft it's usually on take off at night in VMC at airfields in spasrely populated areas where there are few visual clues.

[olasek]

This means that pilots of low powered GA aircraft are just as susceptable as jet pilots. And the staistice reflect this.

Correct. Actually this sort of accidents are fairly common place in GA, rather rare among professional airline pilots. I don't think a type of aircraft has much to do with it, just pilot training and experience.

[Prada]

More about Illusions

There is a nice Article about piloting illusions. Good to read.

Sensory illusions in aviation - Wikipedia, the free encyclopedia

[jimjim1]

Aerobatic trainer

The Ancient Greek sagely mentioned:

A few hours per year in an aerobatic trainer should be part of maintaining currency and is not expensive.

My feeling is that if all airline pilots did this then some would likely die in the process since GA flying is quite a bit more hazardous that airline flying. It might reduce the total deaths from air travel but at the expense of increasing the occupational hazard of being an airline pilot.

Would that be an acceptable trade off?

[olasek]

then some would likely die in the process since GA flying is quite a bit more hazardous that airline flying

No, GA is more hazardous primarily because of GA pilots making poor flight decisions so I have hard time with the premise of your argument that a professional ATP pilot flying in GA airplane is automatically at much higher risk level, there are many safe pilots who fly GA their whole life and never get into any trouble. Yes, some pilots will always die - for example crashing while driving to the airport.

[fireflybob]

Am sure SI exists and occurs with pilots.

Question is why/how do some crews sort it (viz example in B757 above) but others don't?

I've had disorientation on several occasions when airborne but lived to tell the tale,

The answer is thorough crew training and procedures - plenty of a/c do GAs in potentially disorienting situations but do not come to grief.

Ref this being "common place " in GA a/c accidents - can you supply statistics?