PARIS — Confronted with faulty instrument readings and alarms going off in the cockpit, the pilots of an Air France jetliner struggled to tame the aircraft as it went into an aerodynamic stall, rolled, climbed and finally plunged 38,000 feet into the Atlantic Ocean in just 3 1/2 minutes.
But the passengers on that doomed Rio de Janeiro-to-Paris flight were probably asleep or nodding off and didn’t realize what was going on as the aircraft plummeted nose-up toward the ocean, the director of the French accident investigating bureau said after releasing preliminary data from flight recordings that provide new insight into the June 1, 2009, disaster. All 228 people aboard the Airbus A330 died.
The brief, highly technical report by the Bureau of Investigations and Analyses, or BEA, contains only selective remarks from the cockpit recorder, offers no analysis and assigns no blame. It also does not answer the key question: What caused the crash?
Several experts familiar with the report said the co-pilot at the controls, at 32 the youngest of the three-man cockpit crew, Cedric Bonin, might have responded incorrectly to the emergency by pointing the nose upward, perhaps because he was confused by the incorrect readings.
The plane’s external speed sensors, called Pitot tubes, have long been considered a likely culprit in the disaster, with experts suggesting they might have been iced over.
The BEA investigators found that two sets of instruments on the plane gave different speed readings, with discrepancies lasting about a minute.
An official at Airbus said the aircraft’s nose should have been slightly angled to enable the plane to regain lift after it had gone into an aerodynamic stall. “This is part of the general pilot training for any aircraft,” said the official.
Other aviation experts concurred. In an aerodynamic stall, a plane most often loses lift because it is traveling too slowly, and begins to fall. Pointing the nose downward enables the aircraft to pick up speed, gain lift and pull out of the stall.
