“We do have an issue in aviation that needs to be dealt with,” the chairwoman of the safety board, Deborah A. P. Hersman, told reporters during a break in the hearing.
The captain and the supervising pilot in the Asiana crash — in which a Boeing 777 hit a sea wall short of the runway, killing three passengers — said they thought a system that is used to control the plane’s airspeed was running, although it was not. And all three pilots overlooked a prominent display that showed their airspeed was too low.
According to documents released by the board, for 19 seconds leading up to the crash the pilots had a clear view of guidance lights on the field that indicated they were flying too low, but they did not follow company procedure to break off the approach.
The plane’s captain, Lee Kang Kuk, told investigators — although he was wrong — that he believed the protection system in the Boeing was similar to the one in the Airbus A320, which he had substantially more experience flying.
In the Boeing, the throttle levers — one for each of the two engines and located on a center pedestal between the captain and the first officer — will move as the automatic system manipulates the engines. In the Airbus they will not move even when the auto-throttle adjusts the engines’ power.
The captain was supposed to keep a hand on the throttle levers to feel them move, and he did so on and off, he told investigators. Lack of movement in the throttle levers did not trouble him, he told investigators, because he thought the auto-throttle would “wake up” and maintain a safe minimum speed with no sign.
Boeing’s design leaves more discretion to the pilot and does not always ensure that the engines will maintain a minimum speed. Asiana ground school instructors warned the crews that the auto-throttle would be disabled when autopilot was being used by the crew to control the plane’s descent to a certain altitude, according to one safety board document, but the lesson evidently did not stick.
Captain Lee told investigators that any of the three pilots on the plane could have decided to break off the approach, but he said it was “very hard” for him to do so because he was a “low-level” person being supervised by an instructor pilot.
He also said that as the plane approached, he was momentarily blinded by a light on the runway, possibly a reflection of the sun, but that he would not wear sunglasses because that was considered impolite among Koreans.
The pilots did know they were descending too fast. One said so about a minute before impact, in English, which the crew was using on approach, according to a transcript of the flight data recorder. The second mention was also in English, but the third, about nine seconds after the first, was in Korean, a clue in the transcript about the urgency in the cockpit.