Pilot error? Software issue? Or a combination of both?
Those are the questions lingering after Boeing and Asiana Airlines submitted reports today to the National Transportation Safety Board regarding flight 214, which crashed upon descent at San Francisco International Airport last July. Three passengers were killed during the landing, and more than 200 were injured.
Boeing and Asiana agreed that the flight crew “did not ensure a minimum safe airspeed.” However, Asiana pointed to other factors, which it said contributed to the crash, namely software issues.
According to Asiana Airlines report to the NTSB:
The crash of flight 214 was the result of a unique and complex chain of interrelated events. The record makes clear that the flight crew members were thoroughly trained and well-equipped to complete the approach to SFO without incident. Nevertheless, the accident flight crew did not ensure a minimum safe airspeed. The investigation also reveals, however, a number of other contributing causes of the accident, including inconsistencies in the B777’s automation logic that led to the unexpected disabling of airspeed protection, a low airspeed alerting system that activated too late to permit recovery of the flight, and air traffic control demands that led to excessive pilot workload during final approach.
Earlier this year in a simulator in Seattle, test crews from Boeing and the FAA recreated the situation from flight 214.
Significantly, the test pilot also acknowledged being confused by the B777’s automation on the test flight that experienced a large airspeed deviation. He explained that he was “[c]onfused about why speed [was] low,” and that he “thought [autothrottle] was not working right.”
Boeing, however, came to a different conclusion in its report, noting that “the airplane and all airplane systems were functioning as expected prior to impact and did not contribute to the accident.”
This accident occurred due to the flight crew’s failure to monitor and control airspeed, thrust level and glide path on short final approach. This accident would have been avoided had the flight crew followed procedures and initiated a timely go-around as the approach became increasingly unstable in relation to the stabilized approach criteria.
The NTSB plans to continue to investigate the matter and issue a final report on what happened when the plane from Seoul made contact with the seawall at the busy airport.
Here is Boeing submission to the NTSB.
And here is the submission by Asiana: