A federal aviation official has revealed that the plane that crashed into a house near Buffalo, killing 50 people, was on autopilot when it went down, a possible violation of airline policy in icy weather.
Steve Chealander, of the National Transportation Safety Board, said the plane's airline, Colgan Air, recommends pilots fly manually in icy conditions, and requires them to do so when there is severe ice.
Pilots of the doomed plane discussed "significant" ice buildup on the wings and windshield just before crashing on Thursday night.
Other aircraft in the area told air traffic controllers they also experienced icing around the time that the plane went down.
Colgan Air operates a fleet of 51 regional turboprops, including Continental Connection, United Express and US Airways Express. Chealander said the preliminary investigation indicated the autopilot was still on when the plane crashed.
The remains of 15 people have so far been recovered from the wreckage of Flight 3407, as crews raced to finish their work before a snowstorm arrives later in the week.
Once all the remains are recovered, the focus will turn to removing wreckage of the 74-seat aircraft from the residential neighbourhood where it went down near the end of a flight from Newark, New Jersey.