The approach to San Francisco International Airport stressed the pilot of Asiana Airlines Flight 214, which crashed landed in July, according to a report released by the National Transportation Safety Board.
The 45-page document determines that the autopilot was disconnected and the autothrottle changed from “thrust” to “hold” when the plane was up 1,600 feet, and the pilot called out “manual flight.”
Three passengers died in the crash, as the plane approached San Francisco airport at 103 knots instead of the ideal 137 knots, causing it to hit the seawall, split into parts, and burst into flames.
The pilot in training told investigators he believed the autothrottle in the Boeing 777-200ER “was always working”, before the plane came in at a low altitude and speed, while attempting to land.
The report states two other pilots had warned the trainee, during a class in April that if the autothrottle goes to “hold”, it would not automatically re-engage in a descent.
“The ground school instructor stated that he provided this training because he had personally experienced, in flight, an unexpected activation of HOLD mode and thus the failure of the autothrottle to re-engage,” the report stated.
Pilot Lee Gang Guk told the NTSB that he found the approach to San Francisco International Airport “very stressful” and “difficult to perform” with such a large plane.
Guk was landing for the first time at San Francisco after spending just 33 hours flying the Boeing 777, although he had close to 10,000 hours of experience on other planes. Another one of the pilots, Lee Jeong Min, had spent 3,220 hours flying 777s.
The report states that when the NTSB asked the captain-in-training how confident he felt about his knowledge of the 777 autoflight system, he responded he didn’t feel so confident and needed to study more.
The NTSB released the report on Wednesday, at the beginning of an 11-hour hearing to look into the causes of the crash at San Francisco airport.
Deborah Hersman, NTSB chairman, stated the hearing will not assign blame or make recommendations, but will look into how and why the crash in San Francisco happened.
“We meet to learn lessons,” Hersman said.
Boeing designed the 777 with low speed warnings that notifies pilots of problems with the autoflight system, starting with a yellow light with sound to a red light with continuous sound that says “airspeed low.”
The instructor pilot in the San Francisco crash testified that he heard the low speed warning, however the flying pilot says he did not hear it.
First officer Bong Dongwon, called out “sink rate” numerous times about one minute before the crash, to warn the flying and instructor pilots that the plane was descending at the wrong rate. Dongwon told investigators he noticed a “little late response” on the two pilots’ parts.
The voice recorder recovered from the plane, shows at 1.5 seconds before impact a crew member is heard suggesting they abort the San Francisco landing, but at that point it was too late.
Other issues being addressed at the hearing relate to the 16-year-old passenger who was thrown from the plane, covered in foam from fire extinguishers, and run over by a fire truck.
Investigators are also looking into emergency slides malfunction, after one didn’t deploy properly, pinning a flight attendant for a time, while others didn’t deploy at all.
Initially, investigators into the San Francisco crash suggested the Korean culture, which prevents subordinates from challenging superiors and could explain the relatively quiet cockpit, might have played a role in the accident.