SAN FRANCISCO — "Research would tell you that crew pairing with the same people over longer periods of time is safer," she said. "When two people fly together all the time, you get into a routine that's more efficient. You have experience communicating."
Details emerging from Asiana pilot interviews, cockpit recorders and control-tower communications indicate that Lee Gang-kuk, who was halfway through his certification training for the Boeing 777, and his co-pilot and instructor, Lee Jeong-Min, thought the airliner's speed was being controlled by an autothrottle set for 157 mph.
Inspectors found that the autothrottle had been "armed," or made ready for activation, Hersman said. But investigators are still determining whether it had been engaged. In the last two minutes, there was a lot of use of autopilot and autothrusters, and investigators are going to look into whether pilots made the appropriate commands and if they knew what they were doing, she said.
When the pilots realized the plane was approaching the waterfront runway too low and too slow, they both reached for the throttle. Passengers heard a loud roar as the plane revved up in a last-minute attempt to abort the landing.
The two pilots at the controls during the accident had also been in the cockpit for takeoff. Then they rested during the flight while a second pair of pilots took over. The two pairs swapped places again about 90 minutes before landing, giving the trainee a chance to fly during the more challenging approach phase.
Hersman cautioned against speculating about the cause of the crash. But she stressed that even if the autothrottle malfunctioned, the pilots were ultimately responsible for control of the airliner.
"There are two pilots in the cockpit for a reason," she said Wednesday. "They're there to fly, to navigate, to communicate and if they're using automation, a big key is to monitor."