Confusion in Reporting of Turkish Air 1951 Crash

Posted on 27. Feb, 2009 by in Featured

Reporters are confused over the definition of STALL in aviation. A stall has absolutely nothing to do with the engines. In aviation, it is defined as the air flow boundary layer separating from the wing, the wing stops producing lift and the aircraft stops flying. A stalled wing will cause an aircraft to “literally [fell] out of the sky” as Dutch Safety Board Chairman Pieter van Vollenhoven was quoted.

Above is a good video of the flow over a wing and the disruption at stall. The red lines are yarn attached at the leading edge, watch as the yarn swirls at stall. Also notice no engine(s)!

We know from US Air 1549 that an airplane does not fall out of the air when the engines fail. However we also know from the British Air 777 that crashed in London, that if they quit on final your options are very limited. With gear and flaps extended you are coming down now; the critical action the crew must perform is to maintain enough speed to break the rate of descent and cushion the impact to allow survival. The crews, to all their credit, were able to do that in London and Amsterdam.

The Turkish Pilots Association is now claiming wake turbulence is the probable cause; other articles are sighting engine failure and fuel starvation. This is why you must use caution when commenting on accidents under investigation; speculation runs wild.

IMO, the only thing evident is that the aircrafts wing stalled or came very close, and the crew was able to regain enough lift to cushion the impact ensuring most of their passengers survived. Wing tip vortices, fuel starvation, engine failure or flight crew error (there are reports the apprentice pilot was at the controls) could all account for it. We will not know until the safety authorities analyze the flight data recorders. Until then, everything is speculation.

No Responses to “Confusion in Reporting of Turkish Air 1951 Crash”

  1. Rick 1 March 2009 at 14:30 #

    Now I’ve read the aircraft immediately preceding the 737 was a 757…now wake turbulence is a possibility.

  2. Chip 1 March 2009 at 17:31 #

    I saw that, if you click on Turkish Pilot Association above you can read the article. I still think it is too early for anyone including the TPA to declare definitively what happened. I think we will hear more tomorrow and it will be definitive.

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