Investigators sifted through wreckage and searched for bodies on Saturday after a commuter plane nosedived into a western New York state neighborhood on Thursday night, killing 50 people.

National Transportation Safety Board investigators and FBI agents were hunting for clues to what caused the Dash 8 Q400 turboprop plane to pitch wildly in its final approach and slam into a house in the Buffalo suburb of Clarence Center.

Speculation continued to focus on the wintry weather, with the crew reporting snow and mist and commenting on ice buildup on the windshield and front edge of the wings shortly before the crash, according to the cockpit voice recorder tapes.

Some 75 workers began the delicate and gruesome task of recovering remains from the site about six miles (10 km) from the Buffalo airport. Bodies were being taken to the Erie County medical examiner for identification.

"In some cases, we'll need to use DNA. In some cases, maybe we won't," Dr Anthony Billittier, Erie County's health commissioner, told the Buffalo News.

Investigators were due to give a briefing to the media later on Saturday. Access to a wide area around the crash site was being restricted to residents.

All 49 people on the plane and one person in the house were killed. Firefighters worked well into Friday to put out a blaze fed by jet fuel and a natural gas leak.

Flight 3407 to Buffalo from Newark, New Jersey, was operated by Colgan Air for Continental Airlines. Colgan is a unit of Pinnacle Airlines.

The plane's manufacturer, Canada's Bombardier Inc, said it was the first fatal crash of a Dash 8 Q400.

RESPECT AND CARE

"FBI agents, NTSB personnel and all our law enforcement partners will treat the scene with much respect and care, ensuring that the proper dignity is provided to the victims," said Laurie Bennett, special agent in charge of the Buffalo FBI office.

Special care will be taken in retrieving personal effects "in the hopes that the families can obtain closure in the many months and years ahead," Bennett told the Buffalo News.

As the plane descended towards the airport with its landing gear down, its nose suddenly and violently moved up and down and its wings see-sawed, investigators said after reviewing flight data and cockpit voice recorders.

"Shortly after that the crew attempted to raise the gear and flaps, just before the end of the recording," Steve Chealander of the NTSB said on Friday.

The crash was the first deadly accident for U.S. airlines since August 2006, when a similar number of people were killed when a Comair jet crashed on takeoff in Kentucky.

It was the third fatal accident since 2003 for Pinnacle and its Colgan unit, according to safety records. The two previous flights, which were not carrying passengers, resulted in the deaths of four crew members.

Thursday's disaster came less than a month after the successful crash landing of a US Airways jetliner on the Hudson River in New York City.

All 155 people on board survived when pilot Chesley "Sully" Sullenberger brought the plane down safely on the river after it hit birds, taking out both engines.