In documents filed with federal accident investigators,
Asiana's assertion about the throttles was immediately countered by
Asiana and Boeing filed their reports with the
The Asiana jetliner struck a seawall at the end of the San Francisco runway, shearing off the tail section and ejecting three flight attendants who were still in their seats. Wreckage was scattered across the airfield as the jet spun around.
Asiana told the National Transportation Safety Board that the auto throttles had major design flaws related to its settings that misled pilots into believing the system was maintaining the airspeed. The system also lacked an alerter to warn pilots when their speed sharply declined, the report stated.
Airline officials noted that U.S. and European aviation officials have had similar concerns and warned Boeing about the matter.
The South Korean airline conceded, however, that its pilots failed to monitor and maintain the required speed and altitude during the final approach for landing.
The trainee captain at the controls told investigators he was concerned about his ability to land the plane manually without automated systems. He said that the approach was very stressful and that he mistakenly thought the auto throttle would maintain the proper speed.
Boeing officials told the NTSB that the airplane's auto throttles, a kind of cruise control for planes, were functioning as expected.
They said that at an altitude of 500 feet, the crew should have noticed that the approach did not conform to established procedures, although they had significant indications that their speed, thrust settings and altitude were not correct.
In addition, the NTSB's preliminary investigation indicated that the auto throttles were working properly the day of the crash and showed "no anomalous behavior."