Board Cites Confusion By Crew In Air Crash
WASHINGTON - The crew members of an Asiana Airlines flight that crashed their Boeing 777 against the sea wall at San Francisco International Airport on July 6 had missed multiple cues that they had done something wrong in the seconds before the crash, according to investigators who met Tuesday to establish the cause of the crash.
But their training was deficient, and they shared widespread confusion about how to use a crucial system, the auto-throttle, according to comments at the meeting, held by the National Transportation Safety Board.
'The flight crew over-relied on automated systems that they did not fully understand,' said Christopher A. Hart, the acting chairman of the board. Crew members unknowingly disabled the auto-throttle, which they thought would keep them from flying too slowly, because they gave multiple instructions to the autopilot during the approach and failed to follow airline procedures in the sequence of instructions and in saying aloud what they were doing.
And despite the fact that the pilot in command had raised the nose to a highly abnormal attitude to slow his too-rapid descent - a cue that the plane was too slow - none of the three pilots in the cockpit reacted until it was too late.
The chief of the safety board's operations group, Capt. Roger Cox, said that the pilot 'needed more active coaching.'
'He showed poor awareness of altitude and airspeed,' Captain Cox said. But in the other seat, where the co-pilot usually sits, was a second captain, who was training the pilot in charge, Captain Cox said. The flight was his first as a solo trainer, and he did not intervene. The crew was counting on the auto-throttle to keep the big plane's speed in a safe range, investigators said.
But Robert Sumwalt, a member of the safety board and a former airline pilot, said that many airline pilots and even some instructors did not understand when the auto-throttle would work and when it would not.
Three young women among the 291 passengers were killed; one of them was left for dead by firefighters and inadvertently run over by two emergency vehicles, according to the investigators. (She was probably covered with firefighting foam at the time.)
While more than 80 percent of the passengers escaped with minor injuries or none, all four of the flight attendants in the rear galley were pulled from the plane when the tail broke off; two more were trapped by emergency slide rafts that inflated because the force of the impact damaged their trigger mechanisms.
The proceedings were translated simultaneously into Korean, the language of the airline, and Mandarin, the language of many of the passengers.
Safety board investigators had spotted within the first few hours the factor that they eventually identified as the immediate cause of the crash: the crew had used the autopilot in a way that disabled the automatic throttle, which none of the three pilots in the cockpit realized. And all three, apparently relying on the automatic system, had stopped paying attention to their airspeed.
The airline, however, tried to broaden the issue and cast some of the responsibility on Boeing's cockpit design. The highly automated cockpit gave an alarm when the speed fell too low, but it gave the warning a few seconds too late to be useful. And the fact that the auto-throttle could be disengaged so quietly amounted to a trap for an unwary crew, the airline said.
The crash raised broader questions about whether crews were over-relying on automation, to the detriment of safety. And investigators said that some of the automation could be improved, to give warnings in a more timely way.
Another broader issue is jet lag. The plane was landing in midday in San Francisco, but it was 3:30 in the morning in Korea, perhaps reducing the crew's attention to detail.
The Asiana crash was the first fatal passenger airline accident in the United States in more than four years. The previous one was the crash of a twin-engine turboprop on approach to Buffalo in February 2009, which killed 50 people, including one on the ground.
At the moment, the board has only one other airline crash on its agenda, the crash of a UPS cargo plane on approach to an airport in Birmingham, Ala., in August 2013.
It is also looking into a host of smaller safety problems, and certainly the system still shows evidence of unsafe actions. In January, a Southwest Airlines crew landed its 737 at the wrong airport, near Branson, Mo. Such mistakes raise the threat of a collision with another aircraft, among other problems.
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