SAN FRANCISCO (AFP) - The Asiana Airlines jet that crashed at San Francisco Airport was "significantly below" its target speed and its pilots asked to abort the landing just 1.5 seconds before impact, US investigators said on Sunday.
National Transportation Safety Board chair Deborah Hersman said that air traffic control received a "call to go around" from the Boeing 777 aircraft and indicated that the engine was about to stall.
"During the approach, the data indicate that the throttles were at idle and air speed was slowed below the target air speed," of 137 knots, Ms Hersman said at a press conference in San Francisco, noting that the plane was cleared for a visual approach given good weather.
Asked about the speed at which the plane was traveling, Ms Hersman stressed "that the speed was significantly below" the target speed.
"We have to take another look at the raw data and corroborate it with radar and air traffic information to make sure we have a very precise speed. But again, we are not talking about a few knots here or there. We're talking about a significant amount of speed below 137," she said.
Two teenage girls from China were killed and 182 people were injured - including more than 40 seriously - when the airliner crashed while landing at the airport on Saturday.
The plane's speed on approach triggered an automatic emergency device called a "stickshaker" to warn the pilots that the plane was about to stall.
Hersman said: "There was a call out for a go around from one of the crew at 1.5 seconds prior to impact. And the call out is a - is communication between the crew that they want to go around, that means they want to not land but apply power and go around and try to land again."
"Everything is on the table. It is too early to rule anything out," she added, noting that her team expected to be at the airport for around a week, probing the crash.