Role of autopilot eyed in Asiana air crash at San Francisco airport
July 10, 2013, 12:01 am TWN
WASHINGTON--The crash landing of a South Korean airliner in San Francisco has revived concerns that airline pilots get so little opportunity these days to fly without the aid of sophisticated automation that their stick-and-rudder skills are eroding.
Federal and local officials on Monday addressed the possibility that the Chinese girl, who along with a classmate comprised the crash's two fatalities, might have been killed accidentally on the runway as the first firefighters raced to the scene.
“One of our fire apparatus may have come into contact with one of our two victims,” Fire Chief Joanne Hayes-White said during a news conference called to highlight the heroic efforts of first responders. “I assure you, we are looking closely at this.”
What is known is that Asiana Airlines Flight 214 crashed short of its target runway on Saturday at San Francisco International Airport in broad daylight in near-ideal weather conditions. The Boeing 777's engines are still being examined, but they appear to have been receiving power normally. And the flight's pilots didn't report any mechanical issues or other problems.
But the plane was traveling far too slowly in the last half-minute before the crash, slow enough to trigger an automated warning of an impending aerodynamic stall.
The wide-bodied jet should have been traveling at 158 mph (254 kph) as it crossed the runway threshold. Instead, the speed dropped to as low as 118 mph (190 kph) before the plane struck a rocky seawall short of the runway. The plane careened briefly and then pancaked down.
The pilot, Lee Gang-guk, had a lot of flying experience but was still new to the plane, having clocked only 43 hours at the controls. He was supposed to be flying under the supervision of another experienced pilot. There were two more pilots on board the Seoul-to-San Francisco flight, as is typical on long flights during which two pilots rest while two fly, and then swap out.
Lee was also flying without the aid of a key part of the airport's instrument landing system, which provides pilots with a glide slope to follow so that the plane isn't too high or low. He was also new to the airport.
And he was manually flying the plane with the autopilot shut off, which other pilots said is not unusual in the last stage of a landing, although some airlines prefer that their pilots use automated landing systems. Still unclear is whether the auto throttle, which regulates fuel to the engines to control speed, was shut off or perhaps unintentionally left in an idle mode.
That might account for the slow speed, but it wouldn't explain why the pilots didn't recognize their peril and act in time to avoid the crash, pilots and aviation safety experts said.
Procedures at most airlines would require all four pilots be present in the cockpit during the landing, which is the most critical phase of flight, pilots said. The NTSB hasn't disclosed whether all four were present.
Rory Kay, a training captain for a major airline who flies internationally, said, “We're all wondering the same thing — why no reaction?”
“If your last dozen landings were autopilot landings and here you are faced with nothing but visual (cues) to deal with, your rust factor would be greater,” said Cass Howell, a former military pilot and human factors expert at Embry-Riddle Aeronautical University in Daytona Beach, Florida. “Too much automation can undermine your flying skills.”