Air France crash pilots lost vital speed data, say investigators

(CNN) -- Pilots of the Air France flight that crashed in 2009 and plummeted 38,000 feet in just three minutes and 30 seconds, lost vital speed data, France's Bureau of Investigation and Analysis (BEA) said Friday.
The pilots got conflicting air speeds in the minutes leading up to the crash, the interim reports states. The aircraft climbed to 38,000 feet when "the stall warning was triggered and the airplane stalled," the report says.
Aviation experts are asking why the pilots responded to the stall by pulling the nose up instead of pushing it down to recover.

Miles O'Brien, a pilot and aviation analyst, said: "You push down on the wheel to gain air speed, perhaps they (pilots) were getting information that the air speed was too high. Pulling the nose up will exacerbate an aerodynamic stall."

The speed displayed on the left primary flight display were "inconsistent" with those on the integrated standby instrument system (ISIS), the report says.

 

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The aircraft experienced some "rolling" before stalling and then descending rapidly into the ocean. The descent lasted 3 minutes and 30 seconds and the engines remained operational, said the report. It plunged at 10,912 feet (3,300 meters) per minute.

At the time of the descent, the two co-pilots and captain were in the aircraft cockpit.