The National Transportation Safety Board’s (NTSB) hearing into the causes of the crash of Asiana flight 214 last year continues to focus on misunderstanding of the aircraft’s systems, with one board member saying “crew competency” was not an issue.

‘“I personally do not believe this is a case of crew competency,” says board member Robert Sumwalt. “I think this is a case of the pilot flying the airplane expecting the airplane would do something… that it wasn’t designed to do.”

Though the NTSB’s hearing is still ongoing in Washington DC, investigators noted that Lee Kang Kuk, the pilot flying the Boeing 777-200ER, told investigators that he was “astonished” that the aircraft’s autothrottle did not maintain speed during the final approach.

Investigators have said the autothrottle transitioned to “hold” mode while the aircraft was set to “flight-level change mode.” In that configuration, the autothrottle does not maintain speed.

Sumwalt notes that other Boeing 777 and 787 pilots have experienced a similar lack of understanding about the interaction between the autothrottle and autopilot systems.

For instance, the ground instructor who taught the Asiana pilot told investigators he had experienced three instances of the autothrottle not maintaining speed, and that he “still didn’t understand it”.

That instructor described the issue as an “anomaly”, Sumwalt says.

“It’s not an anomaly at all,” he adds. “It’s the way the aircraft was designed to operator.”

Sumwalt also notes that a Federal Aviation Administration (FAA) test pilot flying a 787, which has a similar autothrottle system as the 777, told investigators that “he did not understand this feature either”.

In addition, the NTSB asked the head of training for a “large” 777 operator if crews widely knew that the autothrottle, while in hold mode, would not “wake up” while the aircraft is in flight level change mode.

“I don’t think it was widely known at all,” that person told the agency, says Sumwalt.

He says that the Asiana flight 214 pilot may not have received adequate training into the aircraft’s systems.

Investigators also suggest that crew fatigue could have played a role.

“There was evidence of some sleep restriction on the pilot flying and all three pilots had circadian rhythm disruptions,” says an investigator.

At the time of the accident in San Francisco, the pilots’ biological clocks were tuned to the local time in Seoul, which was 03:30, investigators said.

The crew exhibited slower psychomotor reaction times and memory problems, which could have been the result of fatigue, investigators say.

Flight 214 slammed into a seawall at the end of the San Francisco’s runway 28L after the speed decayed to 103kt and the aircraft nearly stalled.

Three people died as a result of the accident.

Source: Cirium Dashboard