South Korea on Friday ordered a 45-day suspension of Asiana Airlines' service to San Francisco as a penalty for one of its planes crashing there last year, the transport ministry said.
Asiana said it would appeal the decision, citing the inconvenience for passengers booked on the once-a-day service between Incheon and San Francisco.
An Asiana Airlines Boeing 777 crashed at San Francisco International Airport in July last year, killing three passengers and injuring more than 180.
In its statement, the transport ministry noted that it could have imposed a 90-day suspension but halved the time penalty in view of the flight crew's efforts to minimise casualties after the crash.
But Asiana argued the penalty was too harsh.
"The company will seek a re-deliberation and also consider a possible legal injunction," the airline said in a statement.
The US National Transportation Safety Board (NTSB) said in June that a mismanaged approach for landing in a highly automated cockpit was the probable cause of last year's incident when Asiana Flight 214 clipped a sea wall with its landing gear, then crashed and burst into flames.
Investigators said captain Lee Kang-Kuk, a seasoned Airbus A320 pilot transitioning to the bigger Boeing 777, cut the autopilot on final approach into San Francisco, where the instrument landing system was out of service on a clear sunny day.
Doing so put the auto-throttle on hold, meaning it would no longer automatically control airspeed, explained investigator-in-chief Bill English.
When the jet dipped below the correct glide path, Lee reacted by pulling the nose up -- but the auto-throttle, still on hold, failed to deliver an expected burst of engine power that would have enabled the airliner to make the runway.