The crew of the commuter plane that crashed into a home near Buffalo, N.Y., late Thursday night had reported "significant ice buildup" on the windshield and edge of the wings, a spokesman for the U.S. National Transportation Safety Board said.
According to a cockpit voice recorder recovered from the crash scene, the crew discussed "significant ice buildup, ice on the windshield and leading edge of the wings," shortly before the crash, said NTSB spokesman Steve Chealander. He said the flight data recorder revealed that the de-ice system was on the "on" positition.
Smaller planes generally use a system of pneumatic de-icing devices filled with compressed air to crack any ice that builds up during flights.
The plane crashed into a house in Clarence Center, sending flames shooting into the sky and killing 49 people on board and one on the ground. Canadian Don McDonald, a technical manager at Pharmetics Inc., a pharmaceutical firm based in Fort Erie, Ont., was among the victims.
The landing gear was placed down and 20 seconds later the flaps of the aircraft were positioned for landing, Chealander said. But within seconds of that command, the aircraft went through a "severe pitch and roll," he said.
The recording ends as the crew attempted to raise the gear and flaps, he said.
Recordings from the cockpit voice recorder and flight data recorder, which were sent to Washington for examination on Friday, were of excellent quality, Chealander said.
Chealander, who said nothing has been ruled out in terms of the cause of the crash, said he didn't want to comment on the specific dangers of ice buidup. But he described it as an "aerodynamic impediment" that can change the shape of the wing.
Amy Kudwa, a spokeswoman for the U.S. Department of Homeland Security in Washington, said there was no indication terrorism was involved.
It was originally thought that there were only 48 people on the flight — 44 passengers, two pilots and two flight attendants. But Colgan Air Inc., a regional carrier for Continental, said another off-duty pilot had also boarded the flight.
The 74-seat Continental Airlines plane was heading for Buffalo Niagara International Airport from Newark, N.J. All those on board died, authorities said, and one person was killed in the house hit by the plane.
The plane struck the two-storey, gabled house at about 10:25 p.m. ET and burst into flames, State Trooper John Manthey said.
The flames coming from the crash were shooting up to 30 metres high soon after the crash, eyewitness Bob Dworak estimated, and the home appeared to be reduced to rubble.
"It landed on the house, clearly a direct hit," emergency services co-ordinator Dave Bissonette said at a news conference early Friday. "It's remarkable that it only took one house."
"As devastating as that was, it could have easily wiped out the entire neighbourhood."
While residents of the neighbourhood where the plane went down were used to planes rumbling overhead, witnesses said this one sounded louder than usual, sputtered and made some odd noises.
Light snow, fog and winds up to 30 km/h were being reported in the area at the time of the crash.
"It was not spiralling at all. The left wing was a little low," eyewitness Tony Tatro said of the plane.
Control tower transmission
In a recording from the Buffalo air traffic control tower, captured by users on the Live Air Traffic Control website, controllers are heard talking to a female pilot in the cockpit of the plane.
During a brief exchange, the controller instructs the plane to come into the airport at 2,300 feet. There is no indication that anything is out of the ordinary.
The controller then tries to get in touch with the flight again and there is no response, after which he asks a nearby Delta Air Lines flight whether they can see the plane.
The male Delta pilot responds "negative."
"There was an aircraft over the mark and we're not talking to 'em," the controller says.
"We have a Dash-8 over the markers that didn't make the airport. It appears to be about five miles [eight kilometres] away from the airport."
The controller then says to send out the state police to look for anything on the ground. The plane crashed about 11 kilometres from the airport.
"I could hear it coming down and it was just like in the movies, where you hear that high-pitched sound," said Keith Burtis, who lives three kilometres from the crash site but was in a shopping mall parking lot less than a kilometre away when the plane went down.
"But I could feel it more than I could hear it. And there was a sinking feeling in the pit of my stomach. It didn't take more than a few seconds to know that it was a plane," Burtis told CBC News early Friday.
The plane's tail section and rear fuselage were largely intact and burning at the scene.
"There was some superficial damage to the houses around [the area]," said Bissonette. About 12 other homes in the area were evacuated, he said.
A man who lived in the destroyed home perished in the crash, officials said. Two others were also in the house at the time of the crash, but sustained only minor injuries.
Family members who gathered at the airport awaiting word on their loved ones were taken to a local seniors centre, where chaplains and grief counsellors were on site. Airline officials were also meeting with relatives.
Continental released a statement early Friday advising family members of those on board to call a support line at 1-800-621-3263.
'Really beautiful country town'
Clarence Center is about 35 kilometres from the Canadian border. The Buffalo airport is a popular destination for Canadians. It is estimated that about 50 per cent of passengers who fly out of Buffalo are Canadians using the U.S. departure point to get cheaper airfares. Flights to U.S. destinations are typically $100 cheaper out of Buffalo than Toronto.
Eyewitness Burtis described the neighbourhood where the plane crashed as "a really beautiful country town, and very peaceful." The area has big country street blocks and homes on large plots, Burtis said.
The damage could have been much worse, Burtis said, had the plane gone down farther west, on the outskirts of Buffalo's tightly knit suburbs.
"It would have been much worse on the ground. It would have been in a more densely populated area."
It is the first fatal crash of a commercial airliner in the United States since Aug. 27, 2006, when 49 people were killed as a Comair jetliner took off from Lexington, Ky. The more than two-year span between fatal plane accidents is a record for U.S. civil aviation.