Auto-throttle failure ruled out for Asiana crash

The National Transportation Safety Board yesterday ruled out problems in the auto-throttle system as a possible cause of the Asiana Flight 214 crash on July 6 in San Francisco, leaving them to focus their investigation on the pilots.

Deborah Hersman, chief of the NTSB, said yesterday in her final briefing that they found no evidence of failure of the auto-throttle, an automatic system that guides a plane at appropriate speeds during landing.

“Investigators examined 220 of a total of 1,400 articles recorded on the flight data recorder (FDR), or black box, and found that the aircraft’s engines and other devices, including flight-control surfaces, the autopilot, the auto-throttle and the flight director, operated normally,” she said.

Instead, she said the pilots failed to recognize that they were coming in too low and too slow.

“We examined the cockpit voice recorder carefully, but there was no mention of it until about nine seconds before impact when they’re at 100 feet and one of the pilots called a ‘go-around,’ or aborted landing, three seconds before impact and the other pilot made the same call 1.5 seconds before the crash in a hurry.”

She also said that controllers at the airport who manage many types of information, including determining orders of landing for incoming flights and informing pilots about distances between aircrafts, made no mistakes.

“There was no problem for the controllers,” Hersman said. “They communicated with the pilots until 90 seconds before impact and it was controllers who called for the rescue, not the captain of the flight right after the crash.”

On Wednesday local time, the pilots told the NTSB investigators that the airport controllers warned them they were approaching at low altitude and slow speed only seven seconds before impact, meaning that the NTSB contradicted the pilots’ testimonies.

As the agency concluded that there was no mechanical malfunction and the airport controllers didn’t make any mistakes, it puts the focus of the safety probe on the pilots - Lee Gang-guk, 45, and Lee Jeong-min, 48.

“We should say we believe what she [Hersman] says because she is the chief of the agency, but the FDR really needs to be examined more carefully,” a spokesman of the Ministry of Land, Infrastructure and Transport said. “It isn’t right to open the analysis result of the FDR this early.”

The NTSB team will soon head back to Washington for further investigation and the agency’s final evaluation is expected to take more than a year.

BY KWON SANG-SOO [sakwon80@joongang.co.kr]