Investigators have finished interviewing three of the pilots of Asiana Flight 214, and it’s slowly becoming clear what happened in the moments before the Boeing 777 hit the ground short of the runway, killing two passengers and injuring dozens of others.
National Transportation Safety Board (NTSB) Chairman Debbie Hersman has released some key points from the interviews, cautioning that the information has not yet been corroborated with the flight data recorder and cannot yet be used to determine the cause of the accident.
Here’s what we know about what happened in the cockpit in the moments leading up to the crash:
The Pilots In The Cockpit
There were four pilots in the plane. On long haul flights like this one from South Korea, they take turns flying in pairs.
As the 777 approached for landing, the flying pilot — the one controlling the plane — was sitting in the left seat. He had a lot of experience with the Boeing 737 and 747, and the Airbus A320, and was in training for the 777. He had logged just 35 hours in the jet (Reuters reported on Sunday he had 43 hours experience.)
Sitting in the right seat was an instructor pilot, with about 3,000 hours experience in the 777. A Korean Air Force veteran, he was on first trip as an instructor pilot. He had never before flown with the other pilot.
Sitting in the jump seat (a folding seat in the cockpit) was the relief first officer, who was off-duty at the time. The flight’s fourth pilot, also off-duty, was in the cabin during the impact. He will be interviewed on Wednesday, Hersman said.
Coming In For Landing
The instructor pilot realised the aircraft was slightly high (relative to the recommended height at that point in the descent) when it passed 1,400 feet, and set the rate of descent to 1,500 feet per minute.
At 500 feet, based on the precision approach path indicator (PAPI), he saw the plane was too low.
(A landing system called the glideslope, which provides vertical guidance to keep the plane at the right elevation and angle during its approach, was out of service at the time.)
At this point, he told the flying pilot (the one in training) to pull back, and set the speed to 137 knots, the target speed for landing.
The instructor pilot told investigators he “assumed [the] autothrottles were maintaining speed,” Hersman said during the press conference. Autothrottles automatically meter how much fuel is used, to attain a selected speed.
Between 500 and 200 feet, the aircraft had a lateral deviation, and the PAPI indicated it was even lower, relative to where it should have been, than it was before. The instructor pilot established the 777’s attitude (its orientation) for an aborted landing. He went to push the throttles forward to increase speed, he told the NTSB, but found it had already been done.
A few moments later, plane’s main landing gear hit the seawall at the edge of the San Francisco Bay. The tail broke after it hit the seawall, and two flight attendants were thrown out the back of the plane. Both survived, with unspecified injuries.
The 777 yawed left (spun around its centre of gravity), then spun 360 degrees, Hersman said. After the crash landing, none of the pilots were tested for drugs and alcohol.
What All That Means
As Hersman noted, it is still too early to draw conclusions about what caused the crash. But it’s clear that the plane was flying well below the target speed on its final approach. The fact that the instructor pilot thought the plane was automatically maintaining its speed is a possible reason for the discrepancy.
Asked if there was a backup system in place to warn pilots when the aircraft is not properly set up for landing, Hersman said that it is up to the pilots to monitor airspeed and altitude.
“Let me be clear, the crew is required to maintain a safe aircraft,” she said. “One of the very critical things that needs to be monitored on approach to landing is speed.”
She added that the NTSB will not determine the probable cause of the accident while it is still on site in San Francisco. Investigators are expected to remain there until the end of the week.
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