BBC NEWS | Americas | Crash plane 'dropped in seconds'

A plane that crashed onto a house in New York state, killing 50 people, dropped by 800 feet (245 metres) in five seconds, officials say.

Air safety official Steve Chealander said the plane had fallen from 1,800ft to 1,000ft shortly before impact.

He also said investigators had not found that there were "severe icing" conditions, which would have required pilots to fly the plane manually.

The plane's autopilot was on until just before the crash, Mr Chealander said.

Analysis of the plane's data recorders shows the crew noticed significant ice build-up on its wings before the crash.

Mr Chealander, a spokesman for the National Transportation Safety Board (NTSB), had earlier told the the Associated Press news agency that the NTSB recommended pilots disengage their craft's autopilot facility in icy conditions.

Pilots using manual controls may be able to sense a problem sooner than the autopilot, he said.

But in a press briefing on Sunday he said there was no evidence that the Continental Airlines pilot had done anything wrong.

"The only restriction that they see - the manufacturer of this airplane - and that they write about is that disengage the autopilot in severe icing conditions," Mr Chealander said.

"Thus far we haven't determined that it's severe icing so, so far we see that everything seemed to be normal in using the autopilot."

Pitches and rolls

The Bombardier Dash 8 was approaching Buffalo's airport when it crashed flat on the house in Clarence Center, a suburb of Buffalo, last Thursday.

BOMBARDIER DASH 8 AIRCRAFT The Canadian-made Bombardier Dash 8 Q400 was delivered new last year Q400 is newest member of the Dash 8 family Twin-engine turboprop, mainly for short-haul flights First flown in 1998, entered commercial service in 2000

The pilots did not tell air traffic controllers of any problems during the flight, and a recording of communications appears normal until shortly before the crash.

At that point, the crew are heard discussing snowy and misty conditions and asking for permission to descend.

The crew then discussed "significant ice build-up" on the windshield and leading edge of the aircraft's wings, Mr Chealander said on Friday.

The plane's de-icing system had been switched on before the crew talked about the ice, he said.

Preliminary investigations suggested the plane was pointing away from the airport at which it was meant to land when it crashed.

Analysis of the data recorders shows the plane made a series of severe pitches and rolls seconds before plunging into the house.

The dead include 44 passengers, four crew and one off-duty pilot on board, and one person on the ground.

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