The flight data recorder of doomed Continental Connection Flight 3407 shows the plane dropped 244 metres in five seconds just before it crashed into a home outside of Buffalo, killing 49 people on board and one on the ground.
Steve Chealander, a National Transportation Safety Board spokesperson, said the data indicates the plane pitched upward at an angle of 31 degrees then downward 45 degrees in its final moments.
It also rolled to the left at 46 degrees and then snapped to the right at 105 degrees.
Investigators also revealed that the plane was set on autopilot until just before it crashed-- a violation of airline policy on flying in icy conditions.
The crew of Continental Connection Flight 3407 reported "significant" ice on the plane's wings and windshield moments before the crash Thursday night.
But investigators say the flight data does not show a significant amount of ice buildup.
Colgan Air, which operated the Canadian-made Bombardier Q400, recommends pilots fly manually in icy conditions. In severe conditions, the policy becomes a requirement.
Chealander said Sunday the plane appears to have been set on autopilot until just before it crashed, according to a preliminary investigation.
"You may be able in a manual mode to sense something sooner than the autopilot can sense it," Chealander told The Associated Press.
Automatic safety devices put the plane back into the pilot's control, just before it dropped from the sky.
Earlier this weekend, investigators said the plane landed flat on the house, and was pointed in the opposite direction of the airport where it was supposed to land.
Chealander said the wreckage of Flight 3407 indicates the plane did not nose-dive into the house as previously thought. The flight was supposed to land on a southwest runway, but crashed with the nose facing northeast.
Possible explanations are that that the plane was spinning when it crashed or that it flipped on impact.
Questions
The flight crew began noticing significant buildup of ice on the wings and windshield not long before the plane slammed into a house in Clarence Center, a bedroom community just outside of Buffalo. Two women escaped the home, which burned for hours.
Investigators say that that the plane's deicers were turned on and both prop engines appear to have been functioning properly.
Chealander said the advanced deicing system was engaged 11 minutes into the flight and remained on until the crash.
The NTSB has said that the aircraft underwent "severe" pitch and roll after the flaps were engaged in preparation for a landing. The plane crashed within a 30 seconds after the flaps were engaged.
Moments before the crash, a "stick shaker" mechanism activated to warn the pilot that the plan was about to lose aerodynamic lift - meaning the plane was about to stall. When the stick shaker engaged it would have pushed the nose of the aircraft toward the ground to increase lift.
Investigators say it could take as long as a year to finish a full report on the crash.
A grim recovery
By Sunday afternoon, authorities had recovered the bodies of 15 people.
Canadian Don McDonald of Fort Erie, Ont., was among those killed in the crash.
Also among the victims was Beverly Eckert, who became an outspoken advocate for families of the victims of 9-11 after her husband was killed at the World Trade Center, as well as Alison Des Forges, one of the world's top researchers into the Rwandan genocide.
Flight 3407 was travelling from Newark, N.J. to Buffalo and went down about eight kilometres short of the airport.
Before Thursday, the Bombardier Q400 had never been involved in a crash. There are more than 200 of the planes in service around the world, operated by about 30 different carriers.
With files from The Associated Press
