Air France Probe Shows Plane Stalled in 3.5-Minute Near Freefall
By Laurence Frost and Andrea Rothman - May 27, 2011
Air France Flight 447 crashed after the Airbus A330 lost speed and stalled before beginning a three- and-a-half minute plunge into the Atlantic Ocean that killed all 228 people on board, an investigation found.
The findings by the French BEA air-accident investigation bureau show the autopilot disengaged shortly after the pilots had alerted cabin crew of possible turbulence ahead. According to data from the flight recorders, the younger of the two men angled the jet’s nose higher, a position the aircraft maintained until its final impact.
The preliminary report sheds more light on the final minutes before the deadliest crash in Air France’s history, with the pilots scrambling to avert disaster as the jet hurtled toward the ocean surface at a speed of 180 feet (55 meters) a second. The data shows that the junior crew member, who was 32 and the least experienced of the three, was piloting the aircraft until less than one minute before the actual crash.
“The question is why the pilot kept giving nose-up inputs when the plane was in a stall,” said Paul Hayes, director of safety at Ascend Worldwide Ltd., a London-based aviation consultant company. “You should put the nose down to recover speed, and away you go.”
Breakthrough Recovery
The investigation achieved a breakthrough after the two flight recorders were recovered from 3,900 meters (12,800 feet) beneath the Atlantic and returned to Paris this month, two years after the jet disappeared into the night on June 1, 2009. All data and voice recordings from the two recorders were recovered in full, after being submersed for two years, the BEA said.
A low-speed stall occurs when an aircraft slows to the point where its wings suddenly lose lift, an incident pilots are trained to overcome. Earlier transmits from the jet had already shown that airspeed sensors, or pitot tubes, made by Thales SA (HO) had failed, presenting pilots with a sharp drop in speed readings on their displays after they entered ice clouds.
The analysis shows that the pilots had favored to climb above the approaching stormy clouds but were prevented from doing so because it wasn’t cold enough for the jet to ascend to that level. The crew alerted flight attendants that they should “watch out” as the approaching zone would move the jet around.
Resting Pilot
With the flight captain resting and the two co-pilots at the controls, the auto-pilots disengaged four hours into the flight. The pilots acknowledged that the speed sensors had failed as they responded by pulling up the nose of the aircraft, voice and data recordings show. A stall warning sounded in the cockpit, the BEA said.
According to the BEA, the co-pilots continued to increase the angle of climb, rising rapidly from 35,000 feet to 37,500 feet. When a third stall warning sounded, they continued to pull back on the controls with the engines set to full thrust and rose to about 38,000 feet, where the plane entered a stall.
Less than two minutes after the autopilot went offline, the chief pilot, Marc Dubois, returned to the cockpit, and the conversation shows he was with his colleagues during the remainder of the flight. It’s routine for pilots to take a break away from the cockpit on long-haul flights, Air France has said.
Last-Minute Control
Dubois never actually took back either his seat or the controls, according to the report. Dubois, 58, had almost 11,000 hours of flight experience, compared with fewer than 3,000 hours for the youngest member of the cockpit. The third member of the crew, 37, was given control in the last minute before impact.
Air France said the made a detour to avoid bad weather, and that the pilots showed professionalism, according to an e-mailed statement by the French airline.
With the plane’s nose still pointed up about 15 degrees, the jet began falling at about 10,000 feet a minute, rolling left and right. Almost one minute into the stall, the pilots had reduced engine thrust and tried pushing down on the controls to lower the nose.
Airspeed indications returned and the alarm sounded again as the stalled aircraft picked up some speed, though the plane continued falling until the first co-pilot commented that the aircraft was approaching an altitude of 10,000 feet. The final recordings show the aircraft had fallen back to a speed of about 123 miles per hour (198 kilometers per hour), the BEA said.
‘Technical Observations’
The BEA said its preliminary findings from the black-box data have not yet established any conclusions about the accident’s causes or led to any recommendations. An interim report is due in mid-July. Airbus, the world’s largest manufacturer of civil aircraft, said last week that it had no additional recommendations to operators of the A330 aircraft.
“What we’re publishing today are technical observations, including actions by the crew, which don’t explain the accident,” BEA chief Jean-Paul Troadec told reporters. “Understanding this chain of events and the reasons behind the crew’s actions is a complex task that is just beginning.”
The report concluded that the aircraft remained stalled during its descent, and that the engines were operational and responded to crew commands throughout. Dubois was among the victims recovered from the ocean’s surface in the weeks after the crash, along with debris that included most of the tail fin.
To contact the reporters on this story: Laurence Frost in Paris at [email protected]; Andrea Rothman in Paris at [email protected]
To contact the editor responsible for this story: Benedikt Kammel at [email protected]
By Laurence Frost and Andrea Rothman - May 27, 2011
Air France Flight 447 crashed after the Airbus A330 lost speed and stalled before beginning a three- and-a-half minute plunge into the Atlantic Ocean that killed all 228 people on board, an investigation found.
The findings by the French BEA air-accident investigation bureau show the autopilot disengaged shortly after the pilots had alerted cabin crew of possible turbulence ahead. According to data from the flight recorders, the younger of the two men angled the jet’s nose higher, a position the aircraft maintained until its final impact.
The preliminary report sheds more light on the final minutes before the deadliest crash in Air France’s history, with the pilots scrambling to avert disaster as the jet hurtled toward the ocean surface at a speed of 180 feet (55 meters) a second. The data shows that the junior crew member, who was 32 and the least experienced of the three, was piloting the aircraft until less than one minute before the actual crash.
“The question is why the pilot kept giving nose-up inputs when the plane was in a stall,” said Paul Hayes, director of safety at Ascend Worldwide Ltd., a London-based aviation consultant company. “You should put the nose down to recover speed, and away you go.”
Breakthrough Recovery
The investigation achieved a breakthrough after the two flight recorders were recovered from 3,900 meters (12,800 feet) beneath the Atlantic and returned to Paris this month, two years after the jet disappeared into the night on June 1, 2009. All data and voice recordings from the two recorders were recovered in full, after being submersed for two years, the BEA said.
A low-speed stall occurs when an aircraft slows to the point where its wings suddenly lose lift, an incident pilots are trained to overcome. Earlier transmits from the jet had already shown that airspeed sensors, or pitot tubes, made by Thales SA (HO) had failed, presenting pilots with a sharp drop in speed readings on their displays after they entered ice clouds.
The analysis shows that the pilots had favored to climb above the approaching stormy clouds but were prevented from doing so because it wasn’t cold enough for the jet to ascend to that level. The crew alerted flight attendants that they should “watch out” as the approaching zone would move the jet around.
Resting Pilot
With the flight captain resting and the two co-pilots at the controls, the auto-pilots disengaged four hours into the flight. The pilots acknowledged that the speed sensors had failed as they responded by pulling up the nose of the aircraft, voice and data recordings show. A stall warning sounded in the cockpit, the BEA said.
According to the BEA, the co-pilots continued to increase the angle of climb, rising rapidly from 35,000 feet to 37,500 feet. When a third stall warning sounded, they continued to pull back on the controls with the engines set to full thrust and rose to about 38,000 feet, where the plane entered a stall.
Less than two minutes after the autopilot went offline, the chief pilot, Marc Dubois, returned to the cockpit, and the conversation shows he was with his colleagues during the remainder of the flight. It’s routine for pilots to take a break away from the cockpit on long-haul flights, Air France has said.
Last-Minute Control
Dubois never actually took back either his seat or the controls, according to the report. Dubois, 58, had almost 11,000 hours of flight experience, compared with fewer than 3,000 hours for the youngest member of the cockpit. The third member of the crew, 37, was given control in the last minute before impact.
Air France said the made a detour to avoid bad weather, and that the pilots showed professionalism, according to an e-mailed statement by the French airline.
With the plane’s nose still pointed up about 15 degrees, the jet began falling at about 10,000 feet a minute, rolling left and right. Almost one minute into the stall, the pilots had reduced engine thrust and tried pushing down on the controls to lower the nose.
Airspeed indications returned and the alarm sounded again as the stalled aircraft picked up some speed, though the plane continued falling until the first co-pilot commented that the aircraft was approaching an altitude of 10,000 feet. The final recordings show the aircraft had fallen back to a speed of about 123 miles per hour (198 kilometers per hour), the BEA said.
‘Technical Observations’
The BEA said its preliminary findings from the black-box data have not yet established any conclusions about the accident’s causes or led to any recommendations. An interim report is due in mid-July. Airbus, the world’s largest manufacturer of civil aircraft, said last week that it had no additional recommendations to operators of the A330 aircraft.
“What we’re publishing today are technical observations, including actions by the crew, which don’t explain the accident,” BEA chief Jean-Paul Troadec told reporters. “Understanding this chain of events and the reasons behind the crew’s actions is a complex task that is just beginning.”
The report concluded that the aircraft remained stalled during its descent, and that the engines were operational and responded to crew commands throughout. Dubois was among the victims recovered from the ocean’s surface in the weeks after the crash, along with debris that included most of the tail fin.
To contact the reporters on this story: Laurence Frost in Paris at [email protected]; Andrea Rothman in Paris at [email protected]
To contact the editor responsible for this story: Benedikt Kammel at [email protected]
