SAN FRANCISCO — Federal investigators say two pilots called for the landing of an Asiana Airlines plane to be aborted seconds before the plane crashed at San Francisco International Airport.

National Transportation Safety Board Chairwoman Deborah Hersman said Thursday the first call to abort was made about three seconds before impact. The second call came about 1.5 seconds later and was made by a different pilot.

Investigators have said the plane came in too low and too slow, clipping a seawall at the edge of the runway. Two people died and 180 of the 307 passengers were hurt.

Hersman also said there was no discussion of the flight's speed during the final approach until about nine seconds before impact.