Asiana and Boeing appear to be in conflict over the cause of the fatal crash of an Asiana passenger jet at San Francisco International Airport in July 2013.

On Tuesday, Asiana said that pilot error and defects in the aircraft’s auto throttle system were the combined cause of the crash.

“The probable cause can be found in the very slow air speed that made the B777-200ER stall,” the company said in a statement that came hours after USA Today reported that Asiana acknowledged for the first time that pilot error contributed to the crash.

However, Asiana also blamed the plane’s navigation equipment, saying it “led the crew to believe that the auto throttle was maintaining the airspeed set by the crew.”

Asiana said that due to this defect, the pilots of flight 214, despite being fully qualified to fly the wide-body jet, did not realize the plane was not maintaining the proper air speed as it approached the runway, causing the jet to crash.

Asiana added that the U.S. Federal Aviation Administration, aware of the glitch in the navigation equipment, had asked the B777 manufacturer Boeing to issue an update, but the request went unanswered, sources said.

The local carrier also claimed that “excessive” demands made by San Francisco’s air traffic controllers distracted the pilots on the ill-fated plane. 

Boeing, on the other hand, argued in its report to the NTSB, that the plane and all its systems were functioning as expected before the crash and “did not contribute to the accident,” according to USA Today’s report.

The NTSB is expected to announce its final verdict on the Asiana crash in late June.

By Seo Ji-yeon and news reports (jseo@heraldcorp.com)