- POSTED: 25 Jun 2014 01:14
The US National Transportation Safety Board cited "mismanagement" in the cockpit as the probable cause of last July's crash of Asiana Flight 214 in San Francisco.
WASHINGTON: The US National Transportation Safety Board (NTSB) on Tuesday cited "mismanagement" in the cockpit as the probable cause of last July's crash of Asiana Flight 214 in San Francisco.
At a hearing in Washington, the federal agency cited a number of underlying factors, including insufficient pilot training.
The main cause however appears to be "mismanagement" of what should have been a smooth, stabilized approach of the Boeing 777 into San Francisco airport.
The July 6, 2013 crash - the first involving a commercial airliner in the United States since 2009 - left three dead and 187 injured.
"The Boeing 777 is one of the more sophisticated and automated aircraft in service," acting NTSB chairman Christopher Hart said at the outset of Tuesday's public hearing.
"But the more complex automation becomes, the more challenging it is to ensure that pilots adequately understand it," he said.
"In this instance, the flight crew over-relied on automated systems that they did not fully understand. As a result, they flew the aircraft too slow and collided with the seawall at the end of the runway."
Asiana Flight 214 was completing an otherwise routine 10-1/2 hour journey from Seoul when it clipped the seawall at San Francisco's airport with its landing gear, skidded off the runway and burst into flames.
All three of the fatalities were young Chinese women, including one who was struck by a fire truck beneath a wing covered with firefighting foam.
Investigators testified that she apparently had not buckled her seat belt, and thus had been hurled out of the aircraft on impact.
They also noted, however, that 98 percent of occupants were able to escape the burning aircraft themselves - a fact they credited to the design of the seats and the overall aircraft structure.
The NTSB has previously said the autopilot was switched off about three miles (4.8 kilometres) out, and that the air speed dipped as low as 103 knots (191 kilometres per hour), or 34 knots below the ideal approach speed.
The Boeing 777's descent was so low that an array of approach lights at the end of the runway - a key visual aid to landing - showed four red lights, a situation that would call for an aborted landing.
Due to construction work, the instrument landing system (ILS) in San Francisco was out of order on the day of the crash - requiring pilots to visually guide their airplanes onto the runway.
Central to the investigation has been the Boeing 777's auto-throttle and whether the pilots expected it to "wake up" and power up the aircraft when the airspeed dropped too low - something it did not.
Investigator-in-chief Bill English said Asiana emphasized "maximum use of automation" by its pilots, including the use of autopilots at as low as 1,000 feet (330 meters) from the ground.
He also suggested the pilot flying the approach, Lee Kang-Kuk, a seasoned Airbus A320 pilot transitioning to the Boeing 777, suffered rusty hand-flying skills.
"Pilot skills degrade if not practiced," he added.
Lee was flying into San Francisco with an instructor in the co-pilot's seat, Lee Jung-Min, who himself was freshly certified to train new Boeing 777 pilots.
Another NTSB investigator, Roger Cox, said Flight 214 was instructor Lee's first with a trainee under his wing. Typically, he added, a rookie instructor on such a flight would himself be supervised by an experienced instructor.
NTSB board member Robert Sumwalt, a commercial airline pilot for 32 years, doubted the crash was a case of crew incompetence.
Rather, Sumwalt said, "the pilot expected the airplane to do something for him that it wasn't designed to do."