Everything seemed normal for the first 59 minutes and 34 seconds of Flight 3407 from Newark to Buffalo.
But the last 26 seconds launched a terrifying descent in which the crew tried to regain control of the plummeting plane as it was rolling and twisting, according to information retrieved from the two black box recorders of the ill-fated plane and released Sunday.
A minute before the plane crashed, nothing appeared amiss. The autopilot was controlling the descent at 154 mph, the landing gear and flaps were lowered, and, at 1,650 feet above the ground, the plane was on course for landing on Runway 23 at Buffalo Niagara International Airport.
But 34 seconds later, the plane suddenly went out of control and began a deadly roller-coaster descent that ended at 10:20 Thursday night.
The pilot and first officer heard a warning tone, signaling that the autopilot had automatically disengaged.
Instead of easing toward the landing strip at a gradual descent, the nose of the plane suddenly pitched up at a 31-degree angle, far steeper than what's normal for a plane during takeoff.
At that point, it appears that the crew took over from the autopilot and rammed the throttles all the way forward, trying to prevent the plane from stalling.
Seconds later, the nose of the plane dipped dramatically. At the same time, the plane rolled to the left, its left wing dipping and the right wing pointing up. Then the plane rolled even more dramatically to the other side.
Inside the cabin, passengers and crew felt a gravitational pull of two Gs, twice the force of gravity.
The wings then came back toward level flight. But the nose of the plane still pointed down, and the plane was pointed in the opposite direction from the airport. It had reversed direction.
Continental Connection Flight 3407 also was dropping nearly 20 times faster than normal -- falling 800 feet in 5 seconds. The last recorded data showed the plane 250 feet above ground level, at 115 mph, less than 5 seconds before impact.
Finally, the plane hit flat on the ground, igniting a fireball that took the lives of all 49 people onboard and one in the Clarence Center house it struck.
That is the terrifying sequence of events that federal investigators reconstructed for reporters Sunday evening in a hotel in Amherst.
What caused the plane to pitch out of control and crash remains a question, according to representatives from the National Transportation Safety Board. But some of the details of the final moments of the flight have started coming to light.
It is too early to determine what role icing played, said Steven R. Chealander, the NTSB member overseeing operations locally. The flight's crew had reported "significant" icing on the windshield and leading edge of the wings. "Significant," however, is not a technical term, but merely the words the crew chose to describe what they saw.
Icing is categorized by the Federal Aviation Administration as light, moderate or severe.
"We have not gotten reports yet suggesting it was severe icing," Chealander said.
The takeoff of Flight 3407 was delayed for more than two hours from New Jersey on Thursday night, departing at 9:20. The delay, though, was related to winds as high as 57 mph in the metropolitan New York City area, Chealander said, not because of any weather conditions in the Buffalo area.
"It really was not a bad weather day, and they chose to launch," he told reporters gathered at the Buffalo/Niagara Marriott in Amherst.
The crew turned on the de-icing system 11 minutes after takeoff, and it remained on throughout the flight, he said.
As in most routine flights, autopilot was engaged, controlling the plane's maneuvers prior to landing. But the autopilot shut off just half a minute after the landing gear was lowered, signaling to the flight crew that conditions were too extreme for autopilot to handle.
As federal investigators continue to comb through the evidence, the level of icing is likely to become a key factor. The manufacturer of the twin-engine Bombardier Dash 8 Q400 turboprop recommends that in "severe" icing, autopilot be disengaged so the pilot can correct for weather conditions more efficiently, Chealander said.
In general, the NTSB recommends that when icing occurs, "you might want to disengage the autopilot so you have a manual feel for what might be changing because of the ice," he said.
"We suggest you take it off autopilot to better feel the airplane and stay ahead of changes as a result of the icing," he said.
But the FAA offers a different recommendation to pilots who encounter icing conditions.
This federal agency encourages pilots to "use the autopilot to help you handle the workload in these highly intense weather situations. To say they shouldn't have been flying on autopilot is not correct," Chealander said.
The FAA has not adopted the NTSB's guidelines.
And that point, in the months ahead, may become a point of contention between the FAA, which regulates aviation, and the NTSB, which is charged with investigating various types of transportation accidents.
"The FAA sees things a little differently than we do," said the NTSB's Chealander.
Both organizations are federal agencies under the umbrella of the Department of Transportation. Neither has direct oversight of the other.
Investigators are continuing to dig through the debris on Long Road in Clarence, still searching for the remains of victims, as well as pulling out plane parts. "The plane doesn't seem to have lost anything prior to impact," Chealander said.
Crews have found all six blades to Engine 2, he said. Engine 1 was consumed by fire, but fragments of four blades, all badly burned, have been found.
A crane is being used to lift the engines and put them on the road for investigators to examine, he said.
In addition to its de-icing system consisting of pneumatic boots and electrically heated propellers, the plane also has a related, "sophisticated" system that helps deal with icing, Chealander said.
The NTSB will continue to piece together evidence and try to determine what caused the disaster. But that may require considerable time.
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