失速
飞机乱折腾,上翘下伏,左歪右倒
:confused: The plane was manufactured in April 2008 and went into service that month, the statement said.
Chealander said the stall speed for the aircraft is still being determined. It depends on a number of factors including the gross weight of the plane at the time of the crash.
He said a device that helps the plane avoid stalls in icy conditions was engaged.
Chealander said in the final seconds of flight, the airplane went through a series of up-and-down jerking motions and side-to-side rolls.
Right after that, the so-called stick pusher activating the nose of the aircraft rose to about 31 degrees, according to information recovered from the flight data recorder. The stick pusher will drop the nose of the aircraft in order to gain speed and avoid a stall.
Chealander said he wouldn’t comment on whether the sudden rise of the nose was caused by a pilot reaction to the stick pusher sending the plane into a dive. Following the nose of the airplane going up, the plane then went down to a 45 degree angle.
The plane then rolled about 46 degrees to the left followed by 105 degrees to the right, putting the aircraft onto its side.
He said passengers and crew experienced about 2 Gs of force. One G, or gravitational pull, is what a person standing still would experience.
The last radar hit showed the aircraft was at an altitude of about 900 feet traveling at about 100 knots (115 miles per hour). Radar also indicated the plane fell from 1,800 to 1,000 feet in five seconds, Chealander said.
To contact the reporter on this story: Brian K. Sullivan in Boston at [email protected]
Last Updated: February 15, 2009 20:42 EST |