Safety investigators in the US will investigate whether over-reliance on autopilot systems has degraded human flying skills.
At a two-day hearing starting later today, the National Transportation Safety Board (NTSB) will examine if cockpit complacency caused an Asiana Airlines's jetliner with 307 people aboard to crash land at San Francisco International Airport in July, killing three and injuring more than 180.
Asiana Flight 214 from Seoul came in too slow and too low, causing its tail to strike a seawall just short of the runway. The tail and landing gear came off, and the plane caught fire and skidded down the runway, strewing wreckage and people over a wide area.
So far, there is no evidence of mechanical failure of Boeing’s 777, a plane never before involved in a fatal accident. Instead, investigators have focused on the possibility that the pilots may have mishandled the aircraft's automated controls in the final minutes of flight.
Asiana has ruled out mechanical problems with the plane and has described the pilots as experienced and competent. It has offered victims initial compensation of $10,000 and has vowed to improve pilot training.
The accident has fuelled long-simmering concerns that pilots are relying too much on computers to fly, and losing their ability to manually land a plane when needed.
"It's exactly what they should be talking about," said Robert Schapiro, a retired pilot who has flown internationally for major airlines for 30 years. “Automation is part of what made aviation so fantastically safe. But pilots have become totally reliant on it."
Part of San Francisco airport's automated landing system was out of operation at the time of the crash. The control tower told the pilots to fly a "visual approach," meaning they had to rely on other systems, visual cues and manual skills.
One of those due to be questioned in the hearing is Nadine Sarter, a professor at the University of Michigan, who has studied pilot interactions with automated cockpit controls for decades and is also a member of an FAA working group.
Autopilot systems are highly accurate and reliable, and some airlines require pilots to use them until just before landing, so that they can minimize the chance of mistakes, but the increased complexity "sometimes results in pilot confusion and errors," the working group said in a report.
Some pilots say they are increasingly programming flight controls rather than flying the plane itself, which diminishes their feel for the aircraft, and their ability to respond when something unexpected happens.
After the 6 July crash in San Francisco, the NTSB said the pilots appeared not to notice that the plane was well below its target landing speed and was dangerously close to stalling.
According to the NTSB investigation, the pilots did not react when the plane slowed below the target landing speed of 137 knots (158 miles per hour) as it approached the runway, speed essential to keeping the jet aloft.
With less than a minute left in the flight, and the plane less than 1,000 feet off the ground, the speed slipped below 137 knots. Moments later, at just 103 knots, the pilots tried to abort the landing. But the plane was too close to the ground and struck the sea wall.