Asiana Airlines said for the first time that pilot error was the “probable cause” of the deadly crash in San Francisco last year, according to newly released documents provided to U.S. investigators.
The airline said the pilots were flying too slow and failed to abort the landing in time before the Boeing 777 crashed into a seawall ahead of the runway in an incident that left three people dead and scores injured.
But in its report filed with the National Transportation Safety Board (NTSB) as part of its investigation of the July crash, Asiana claimed there were “inconsistencies” in the plane’s auto throttle that contributed to the crash, USA Today reports.
The airline said the crew of Asiana Flight 214 believed the auto throttle was maintaining the appropriate airspeed without realizing the speed-control feature was inactive. Moments earlier, pilot Lee Kang-kuk had disconnected autopilot and moved throttles to idle — effectively shutting off auto throttle — when the plane unexpectedly began to climb during its descent. A noise alarm sounds when the auto throttle is disconnected, but not when it turns off automatically.
The navigation equipment “led the crew to believe that the auto throttle was maintaining the airspeed set by the crew,” according to the report.
In a separate filing to the NTSB, Boeing said its systems were functioning as expected and the pilots should have aborted the landing.
An FAA test pilot raised concerns over the potential for confusion in 2010, and the FAA “strongly” encouraged Boeing to ensure the auto throttle would “wake up” during significant changes in air speed, but Boeing has not yet changed the software, according to USA Today.