Pilots of the Asiana Airlines Boeing 777-200ER jet that crashed while trying to land in San Francisco are offering an account that differs from the preliminary findings of U.S. investigators, people familiar with the investigation said.
The pilots have told the National Transportation Safety Board that an in-flight malfunction of an automated speed-control system was a major factor in the fatal accident on July 6, these people said.
So far safety-board investigators haven’t uncovered any mechanical or electrical problems with the twin-engine jet prior to impact, these people said. Instead, the NTSB is focused on why the three pilots in the cockpit didn’t adequately monitor the approach and failed to check airspeed until it was too late.
The pilots, according to these people, have told U.S. investigators they believe an automated speed-control system, called auto-throttles, disconnected on its own, allegedly without any warning to the crew, shortly before the Boeing 777 slowed dangerously then slammed into a sea wall in front of a runway at San Francisco International Airport and broke apart.
NTSB officials previously said the cockpit crew “assumed the auto-throttle was maintaining speed,” but investigators also suggested the pilots may have failed to activate it correctly.
“‘Armed’ does not mean ‘active,'” acting safety board Chairman Deborah Hersman id during an on-site news conference in July. When pilots rely on such automation to adjust engine thrust during landings, she said at the time, “a big key is to monitor” the system and keep close track of aircraft speed.
The pilots’ statements-along with details of Asiana 777 maintenance logs showing a number of “uncommanded auto-throttle disconnects”-are part of the arguments Asiana officials intend to make during a planned visit to the NTSB later this year, according to people familiar with the details. The carrier may raise the same issue at a public hearing on the crash the board plans to hold early next year. The NTSB is in charge of the accident probe.
Officials at Asiana and a special South Korean government committee investigating the crash declined to comment. An NTSB spokeswoman couldn’t be reached.
But according to people familiar with the status of the probe, the pilots’ comments are the most detailed effort by the airline so far to explain why an experienced crew may have been lulled into a false sense of confidence.