The pilot flying the Asiana Boeing 777-200ER that crashed 6 July in San Francisco told investigators he was concerned about his ability to conduct a visual approach to the airport that day.
He also expressed uncertainly about the operation of some of the 777s automated flight systems.
“It was very stressful, very difficult to perform a visual approach with a heavy airplane, always,” Lee Kang Kuk, the trainee captain told investigators two days after the accident. “From the planning phase it was very stressful because the glideslope was very, very helpful to making an approach.”
Kuk was relatively new to the 777 and had 43h flying the type. He also had nearly 10,000 hours on 737, 747 and Airbus A320 aircraft, according to the board
The aircraft, operating flight 214 from Seoul, crashed into the seawall in front of Runway 28 Left after a slow and low approach, leaving three passengers dead.
The crew made several adjustments to the flight control computers in the final moments of the flight in an attempt to stabilize the approach.
“Asked whether he was concerned about his ability to perform the visual approach, he said ‘very concerned, yeah,’” according to an NTSB overview of an interview with Kuk two days after the accident. “Asked what aspect he was most concerned about, he said, ‘the unstable approach.’”
The interview also covered Kuk’s knowledge of the flight control computers.
“Asked how confident he felt about his knowledge of the Boeing 777 auto-flight system just prior to the accident, [Kuk] said he was not so confident because he felt he should study more,” the report says. “Asked whether he ... did not feel confident or he had not had enough time to study sufficiently, he said he did not know if he had studied a proper amount; he had just followed the company program.”
Kuk told investigators “his memory was vague about whether he had pushed the “flight level change” switch as the aircraft descended through about 1,600ft, as indicated by accident data.
But such an action was “meaningless because he disconnected the autopilot,” he added.
“He had learned that on the Boeing 777 the autothrottle system was always working,” said the board’s report of its 11 July interview of Kuk. “Sometimes if the pilot wanted, they could disconnect [it], but to him it did not matter because in that situation, he could control the airplane manually... the autothrottle would maintain the speed always.”
But the NTSB says the flight level change function, typically used to climb or descend to a specified altitude, caused the aircraft to pitch up in an effort to climb to its 3,000ft setting.
Kuk said he disconnected the autopilot, and one of the crew moved the autothrottle to “hold” mode, in which it did not control the aircraft’s speed, said the board.
With the autothrottles set to hold, the aircraft slowed to 103kt and nearly stalled before crashing.
Kuk told investigators he had flown into San Francisco many times before as a first officer on Boeing 747 aircraft and that he had landed 747s at San Francisco “once or twice” and manually landed once before, says the report.
While he was a first officer on Boeing 747s, captains “were reluctant to give the flight controls to a first officer because [San Francisco] was a special airport,” said Kuk, according to the NTSB.