(AP) - A commuter plane dropped out of the sky without warning and nose-dived into a suburban Buffalo house in a fiery crash that killed all 49 people aboard and one person in thehome. It was the nation's first deadly crash of a commercialairliner in 2½ years.

The cause of the disaster was under investigation, but otherpilots were overheard around the same time reporting a buildup ofice on their wings - a hazard that has caused major crashes in thepast.

The twin turboprop aircraft - Continental Connection Flight 3407from Newark, N.J. - was coming in for a landing when it went downin light snow and fog around 10:20 p.m. Thursday about five milesshort of the Buffalo Niagara International Airport.

Witnesses heard the plane sputtering before it plunged squarelythrough the roof of the house, its tail section visible throughflames shooting at least 50 feet high.

"The whole sky was lit up orange," said Bob Dworak, who livesless than a mile away. "All the sudden, there was a big bang, andthe house shook."

Two others in the house escaped with minor injuries. The planewas carrying a four-member crew and an off-duty pilot. Among the 44passengers killed was a woman whose husband died in the World TradeCenter attacks of Sept. 11, 2001.

One of the survivors, Karen Wielinski, 57, told WBEN-AM inBuffalo that she was watching TV in the family room in the back ofthe house when she heard a noise. She said her daughter,22-year-old Jill, who also survived, was watching TV in anotherpart of the house.

"Planes do go over our house, but this one just sounded reallydifferent, louder, and I thought to myself, 'If that's a plane,it's going to hit something,"' she told the station. "The nextthing I knew the ceiling was on me."

She said she still hasn't been told the fate of her husband,Doug, but added: "He was a good person, loved his family."

Federal investigators found the black box recorders in theplane's tail that could shed light on what went wrong, but theysaid the smoldering debris was still too hot to remove any bodies.The recorders were on their way to Washington for examination.

No mayday call came from the pilot before the crash, accordingto a recording of air traffic control's radio messages captured bythe Web site LiveATC.net. Neither the controller nor the pilotshowed concern that anything was out of the ordinary as theairplane was asked to fly at 2,300 feet.

A minute later, the controller tried to contact the plane butheard no response. After a pause, he tried to contact the planeagain.

Eventually he told an unidentified listener to contactauthorities on the ground in the Clarence area.

Erie County Emergency Coordinator David Bissonette said itappeared the plane "dove directly on top of the house."

"It was a direct hit," Bissonette said. "It's remarkable thatit only took one house. As devastating as that is, it could havewiped out the entire neighborhood."

The 74-seat Q400 Bombardier aircraft, also known as the Dash 8,in Thursday's disaster was operated by Colgan Air, based inManassas, Va. Colgan's parent company, Pinnacle Airlines ofMemphis, Tenn., said the plane was new and had a clean safetyrecord.

The nearly vertical drop of the plane suggests a sudden loss ofcontrol, said William Voss, a former official of the FederalAviation Administration and current president of the Flight SafetyFoundation, a nonprofit advocacy group.

Voss suggested that icing or a mechanical failure, such as wingflaps deploying asymmetrically or the two engines putting outdifferent thrust, might have caused the crash, he said.

After the crash, at least two pilots were heard on air trafficcontrol messages saying they had been picking up ice on theirwings. "We've been getting ice since 20 miles south of theairport," one said.

Ice on the wings of a plane can alter aerodynamics and interferewith lift and handling. The danger is well known among pilots.

In general, smaller planes like the Dash 8, which uses a systemof pneumatic de-icing boots, are more susceptible to icing problemsthan larger commuter planes that use a system to warm the wings.The boots, a rubber membrane stretched over the surface, are filledwith compressed air to crack any ice that builds up.

A similar turboprop jet crash 15 years ago in Indiana was causedby icing, and after that the NTSB issued icing recommendations tomore aggressively use the plane's system of pneumatic de-icingboots. But the FAA hasn't adopted it. It remains part of the NTSB'smost-wanted safety improvements list.

The National Transportation Safety Board sent a team ofinvestigators to Buffalo. The Department of Homeland Security saidthere was no indication of terrorism.

While residents of the neighborhood were used to planes rumblingoverhead, witnesses said it sounded louder than usual, sputteredand made odd noises.

David Luce said he and his wife were working on their computerswhen they heard the plane come in low. "It didn't sound normal,"he said. "We heard it for a few seconds, then it stopped, then acouple of seconds later was this tremendous explosion."

Dworak drove to the site, and "all we were seeing was 50- to100-foot flames and a pile of rubble on the ground. It looked likethe house just got destroyed the instant it got hit."

The plane was carrying 5,000 pounds of fuel and apparentlyexploded on impact, Erie County Executive Chris Collins said.

The 9/11 widow on board was identified as Beverly Eckert. Shewas heading to Buffalo for a celebration of what would have beenher husband's 58th birthday, said Mary Fetchet, a 9/11 familyactivist.