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Old 31st Oct 2013, 03:11
  #85 (permalink)  
Dan Winterland
 
Join Date: Jun 2001
Location: Blighty
Posts: 4,789
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Lonewolf.

"somatogravic illusion" covers a bit of ground. On a Missed, the addition of power, if you remain on your primary attitude reference (call it Artificial Horizon/Attitude Gyro/Attitude Indicator, or whatever the term is in your aircraft) should not be a "sudden acceleration." Smooth addition of power and increase in pitch is how it's supposed to be done. The illusion in any case is mitigated if your instrument departures in crap weather are flown on the instruments. Pilots do this every day in bad weather.
I doesn't take a sudden acceleration to generate a somatogravic illusion. An acceleration of just 30kts over a period of 10 seconds will produce an acceleration of 1.54m/sē which translates into a perceived pitch up of 9°. As many aircraft will climb at a lesser angle than this, the aircraft can conceivably enter a descent if the illusion is not correctly countered. In recent cases of the illusion, the majority seem to be from GA aircraft taking off at night in areas with few visual clues. Recent airliner crashes caused by the illusion tend to be on Go Arounds - a notable one being the A330 crash at Tripoli on 12 May 2010.

Are you suggesting that pilots are neither trained nor educated regarding this phenomenon?
They are educated. Since the introduction of the Human Performance and Factors course in the early 1990s, it's included in commercial training syllabi. military pilots have been trained in it for far longer - as it was perceived to be a military high performance aircraft phenomenum. However, the HPF theoretical course is usually about as much training as most get. The mitigation for the illusion is emphasised in initial instrument training, but making sure you don't sink on an IF departure is usually as far as it goes.

I've been conduction research into the phenomenum and questiong pilots in my own airline has raised some interesting facts. Most remember the illusion in their HPF syllabus, but many don't really know how it applies to them or what it means. More than a couple had a moment of revalation when I expalined it regarding their experiences. Some had forgptten about it, and some who had trained before the 1990s had never heard of it. Of course, their instrument training provides protection - but still - they had never heard of the phenomenum.

As for training, it's virtually impossible. Wheras the IF syllabus covers other forms of sensory illusions such as the coriolis and oculogyric illusions can be physically demonstrated in the instrument flying syllabus, the somatogravic illusion is nearly impossible to successfully demonstrate in the air. And as simulators simulate acceleration by pitching the pilot up while maintaining the visual and instrument attitudes, quite clearly, they cannot replicate the somatogravic illusion if the human body is being convinced that it is accelerating by tricking the very mechanism which is responsible for the illusion in the first place.

Question for you: Do professional pilots in commercial aircraft not get training and education on this fundamental physiology problem?
Largely yes, but in my opinion, the education does not have sufficent emphasis and is rarely reinforced after initial training. And due to the nature of the problem, the first time a pilot experiences the illusion, it may be many years after initial training, in bad weather, at night during a poorly executed go around. A common set of circumstances in cases where it has been a cause of a crash.



The somatogravic illusion cannot be ruled out in this accident.
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