“The FAA said the ill-fated plane may have collided with something after it landed on the runway’s threshold, with local media showing video clips on YouTube and television footage of the plane’s emergency evacuation slides being deployed and people fleeing the wreckage. Skies seemed to have been clear at the time of the accident.”
—Korea Times
OK, but the ill fated plane should be clearing the runway threshold by 50’ or so. The point here is that the plane should be landing 1000’ to 1500’ from the threshold. The purpose of this is to allow adequate clearance for the landing gear over the threshold. This flight seemed to actually contact the rock berm between the concrete runway and San Francisco Bay! Ouch! It may have “collided” with what?