WASHINGTON – Asiana Flight 214’s pilots caused the crash last year of their airliner carrying more than 300 people by bungling a landing approach in San Francisco, including inadvertently deactivating the plane’s key control for airspeed, the National Transportation Safety Board concluded Tuesday.
But the board also said the complexity of the Boeing 777’s autothrottle and auto flight director – two of the plane’s key systems for controlling flight – contributed to the accident. Materials provided to airlines by Boeing that fail to make clear under what conditions the autothrottle doesn’t automatically maintain speed were also faulted.
The 777 has been in service 18 years and is one of the world’s most popular wide-bodied airliners, especially for international travel. Until last year’s accident, it had not been involved in a single fatal crash.
The board’s acting chairman, Chris Hart, warned that the accident underscores a problem that has long troubled aviation regulators around the globe – that increasingly complicated automated aircraft controls designed to improve safety are also creating new opportunities for error.
The Asiana flight crew “over-relied on automated systems that they did not fully understand,” Hart said.
The South Korea-based airline’s pilot training also was faulted.
Of the 307 people on board, three Chinese teens were killed in the July 6, 2013, crash. Two weren’t wearing seat belts and were thrown from the plane; the third survived but was run over by fire vehicles. Nearly 200 were injured, 49 seriously. It is the only fatal passenger airline crash in the U.S. in the past five years.
Boeing immediately rejected the notion that the 777’s automated systems contributed to the accident.
“The auto-flight system has been used successfully for over 200 million flight hours across several airplane models, and for more than 55 million safe landings,” the company said in a statement. “The evidence collected during this investigation demonstrates that all of the airplane’s systems performed as designed.”
The board didn’t say that the autothrottle failed to perform as designed. But rather that its design, under certain circumstances, could lead to confusion as to whether it was controlling speed or in an inactive state.
Investigators said the flight’s three veteran pilots made 20 to 30 errors during the landing approach.