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Old 26th Oct 2013, 08:34
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rudderrudderrat
 
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Hi Owain Glyndwr,

Thanks for your explanation of the present rules CS 25.
I can only say that it would be a futile exercise as it is virtually impossible to stall an aircraft with the wheels on the ground since it would be attitude limited well below any stall AoA.
The reason for 30 or 60 kts logic is to prevent nuisance stall warnings whist on the ground due to the vanes being blown around randomly.
However it is better to know that you have a false stall warning around 60 kts during the take off than only receiving it once you get airborne with only WOW logic. (see ASN Aircraft accident Lockheed L-1011 TriStar 1 N11002 New York-John F. Kennedy International Airport, NY (JFK)
"...the aircraft lifted off the runway. At that moment the stick shaker activated and the first officer, who was making the takeoff, sensed a loss of performance. The captain than took over control and decided to abort the takeoff. The TriStar touched down again (at a vertical descent rate of 14 feet/sec - the structural design limit being 6 feet/sec -) after being airborne for about 6 seconds."

With the benefit of hindsight of AF447, I still believe it would be better to have had the stall warning on continuously whilst they were stalled, rather than be turned off simply because IAS<60 kts. It must have sounded like a spurious "computer" glitch - and hence be initially disregarded.
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