In the wake of the Asiana Flight 214 crash at San Francisco International Airport (“SFO”), the National Transportation Safety Administration (“NTSB”) recommended on Tuesday that the Federal Aviation Administration (“FAA”) convene a special design certification review of the auto-throttle system on the plane involved, a Boeing 777. Flight 214 struck the seawall at SFO when it came in too low and too slow for landing on July 6, 2013.
The NTSB’s probable cause finding heaped plenty of blame on the pilots, who the NTSB stated “inadequately monitored aircraft performance” in their approach at SFO. The NTSB also, however, blamed as a contributing factor the pilot’s confusion surrounding the plane’s FLCH (Flight Level Change) mode. In the case of Asiana Flight 214, the pilot unknowingly turned off the plane’s auto-throttle system, which would have otherwise maintained a minimum airspeed by automatically increasing power, which he elected to change to FLCH mode.
This change, with the engines at or close to idle, automatically moved the auto-throttle system into hold mode. In many instances, the auto-throttle protection will “wake up” when the speed becomes low. But, when the plane is in FLCH mode, with the auto-throttle protection in “hold”, this is not the case.
The FAA has not announced whether it will investigate if design changes are needed. The FAA rarely uses such a special review, but this is not the first time the confusing nature of the design has been raised as an issue. Boeing has, of course, denied any flaw in the design in the litigation pending against it following the crash.