BUFFALO, New York // The crew of the commuter plane that crashed into a suburban Buffalo, New York, house, killing all 49 people aboard and one person on the ground, noticed significant ice build-up on the wings and windscreen just before the aircraft began pitching and rolling violently, investigators said today. Officials stopped short of saying the ice build-up caused Thursday night's crash and stressed that nothing has been ruled out. But ice on the wings can interfere catastrophically with an aircraft's handling and has been blamed for a number of major air disasters over the years. Continental Connection Flight 3407, bound from Newark, New Jersey, went down in light snow and mist - ideal conditions for ice to form - about nine kilometres short of the Buffalo airport, plunging nose-first through the roof of a house in the suburb of Clarence. All 44 passengers, four crew members, an off-duty pilot and one person on the ground were killed. Two others escaped from the home, which was engulfed in a raging fireball that climbed higher than the treetops and burnt for hours, making it too hot to begin removing the bodies until around nightfall yesterday. Among the passengers killed was a woman whose husband died in the World Trade Center attacks of Sept 11. It was the first deadly crash of a commercial airliner in the United States in two and a half years. One of the survivors from the house, Karen Wielinski, 57, told WBEN-AM that she was watching TV in the family room when she heard a noise. She said her daughter, 22-year-old Jill, who also survived, was watching TV in another part of the house. "Planes do go over our house, but this one just sounded really different, louder, and I thought to myself, `If that's a plane, it's going to hit something.'" she told the station. "The next thing I knew the ceiling was on me." She said she and her daughter escaped in their socks. "I was panicking a little but trying to stay cool,"she said. "I happened to notice a little light on the right of me. I shouted first in case anybody was out there. Then I just kind of pushed what was on top of me off and crawled out the hole. ... The back of the house was gone, the fire had started. I could see the wing of the plane." She said she hadn't been told the fate of her husband, Doug, but added: "He was a good person, loved his family." Investigators pulled the black box recorders from the wreckage, sent them to Washington and immediately began analysing the flight data and listening to the cockpit conversations. Steve Chealander, a spokesman for the National Transportation Safety Board, said at an afternoon news conference that the crew of the twin-engined turboprop discussed "significant ice build-up" on the windscreen and the leading edge of the wings at an altitude of around 3,352 metres as the plane was coming in for a landing. The flight data recorder indicated the plane's de-icing equipment was in the "on" position, but Mr Chealander would not say whether the equipment was functioning. The landing gear was lowered one minute before the end of the flight at an altitude of more than 600 metres, and 20 seconds later the wing flaps were set to slow the plane down, after which the aircraft went through "severe pitch and roll," Mr Chealander said. The crew raised the landing gear at the last moment, just before the recording ran out. No mayday call came from the pilot. Doug Hartmayer, a spokesman for Niagara Frontier Transportation Authority, which runs the Buffalo airport, said: "The plane simply dropped off the radar screen."