Preliminary airplane performance modeling and simulation conducted by the NTSB show that icing had a minimal effect on the stall speed of the Colgan Air Bombardier Q400 that crashed outside Buffalo on February 12, killing all 49 occupants and one person on the ground, the Safety Board said today.
Information from the airplane’s flight data recorder (FDR) indicates that the stick shaker activated at 130 knots, a speed consistent with an engaged de-icing system. FDR data further indicates that when the stick shaker activated, the control column experienced a 25-pound pull force, followed by an up elevator deflection and increase in pitch, angle of attack and g forces. The data indicates a likely separation of the airflow over the wing and ensuing roll two seconds after the stick shaker activated, while the aircraft slowed through 125 knots and while at a flight load of 1.42 gs.
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