Buffalo, N.Y. ? The crew of the commuter plane that fell on a house, killing all 49 people aboard and one person on the ground, noticed significant ice buildup on the wings and windshield just before the aircraft began pitching and rolling violently, investigators said Friday.

Officials stopped short of saying the ice buildup 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, N.J., went down in light snow and mist — ideal conditions for ice to form — about six miles 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 burned for hours, making it too hot to begin removing the bodies until around nightfall Friday.

Among the passengers killed was a woman whose husband died in the World Trade Center attacks of Sept. 11.

It was the nation’s first deadly crash of a commercial airliner in 2 1/2 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 analyzing 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-engine turboprop discussed “significant ice buildup” on the windshield and the leading edge of the wings at an altitude of around 11,000 feet as the plane was coming in for a landing.