The South Korea-based airline said its pilots reasonably believed the plane would continue flying at a proper speed for landing and failed to warn the cockpit crew in time when the plane did not maintain the right speed, according to their statements in a filing made by U.S. accident investigators.
Boeing Co. countered in its own filing with the National Transportation Safety Board that the plane performed as expected and blamed the pilots for the July 6 crash because they stuck with a troubled landing.
"Boeing believes that the evidence supports the following conclusion: This accident occurred due to the flight crew's failure to monitor and control airspeed, thrust level and glide path on short final approach," the airplane manufacturer said.
The Boeing 777 crashed into a seawall at the beginning of a runway while attempting to land. Three passengers died. One of the victims, Ye Meng Yuan, was run over and killed by a rescue vehicle as she lay on the tarmac.
Asiana conceded the crew failed to monitor air speed in the moments before the crash and should have tried to pull back for a second try, according to NTSB reports.
But the airline argued the pilots were reasonable to believe the automatic throttle would keep the plane going fast enough to reach the runway, even though it was effectively shut off after the pilot idled it to correct an unexplained climb earlier in the landing.
The auto throttle did not show that the plane had stopped maintaining air speed and sounded an alert too late for the pilots to avoid crashing, Asiana said.
"The flight crew had an expectation that the auto throttle system was going to do certain things that it did not do," aviation safety consultant John Cox said. "Although they were trained about it, it was not overly intuitive."
The pilot Lee Kang Kuk had been trained to recognize the throttle issue, Asiana said. Lee was an experienced pilot, but was still training to be a captain in the 777 and had less than 45 hours in the jet.
The NTSB has not determined the exact cause of the crash.
The Associated Press contributed to this report.