Pentru cei inca interesati de subiect:
http://www.flightglobal.com/articles/2009/02/15/322581/ntsb-colgan-3407-pitched-up-despite-anti-stall-push.html
http://www.buffalonews.com/home/story/580554.html
Citeva spicuiri:
The crew turned on the aircraft’s automatic de-icing system shortly after departure from Newark.
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Colgan Air Q400 ... pitched 31 degrees nose-up after stick shaker and stick pusher systems activated at the start of the instrument approach.
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data shows that the stick shaker and stick pusher activated roughly 34 seconds after the landing gear was deployed and as the wing flaps transitioned between 5 and 10 degrees down. The pilots had commanded the flaps to the 15 degree down position.
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aircraft had been flying in autopilot mode until the stick shaker activated, an action that automatically disengaged the system.
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Following the initial pitch upset to 31 degrees nose up, ... the aircraft experienced a nose-down pitch of 45 degrees with a roll to the left of 46 degrees. The Q400 then rolled right to 105 degrees. Engine power was increased to full-power about 6 seconds after the upset. The pilots had commanded the flaps and landing gear to retract after the upset.
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He also said that autopilot was engaged at some point into the flight, and it remained on until 26 seconds before the crew lost contact with air traffic controllers.
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When the plane crashed, landed, autopilot was not engaged, he said.
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When autopilot engaged, the airplane's system was attempting to push the nose of the plane down.
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At some point, the crew then disengaged the autopilot, he said.
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While the NTSB has recommended that pilots hand flying their aircraft in icing conditions to get a better sense for trim changes, ... US Federal Aviation Administration has not mandated the practice, in part due considerations over pilot workload in such conditions without the use of autopilot.
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Bombardier, the manufacturer of the Q400, recommends hand flying only if icing conditions are severe.
“From what we’ve seen so far, we haven’t determined there was severe icing,”
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A “reference speed increase” switch that increases by 20kt the speed at which the stall warning system activates had been set to the ON position by the pilots as called for in icing conditions, says Chealander.
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Investigators are still in the process of determining what the aircraft’s stall speed would have been for its weight and configuration
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Chealander says the G-forces during the final minute of the flight ranged from 0.75G to 2G.
Acasa 
