Remains of 15 of 50 victims of Buffalo crash recovered
BUFFALO, N.Y. - The commuter plane that crashed near Buffalo was on autopilot(自动驾驶仪) until just before it went down in icy weather, indicating that the pilot may have violated federal safety recommendations and the airline's own policy for flying in such conditions, an investigator said Sunday.
Federal guidelines and the airline's own instructions suggest a pilot should not engage the autopilot when flying through ice. If the ice is severe, the company that operated Continental Flight 3407 requires pilots to shut off the autopilot.
"You may be able in a manual mode to sense something sooner than the autopilot can sense it," said Steve Chealander of the National Transportation Safety Board, which also recommends that pilots disengage(脱离) the autopilot in icy conditions.
Automatic safety devices returned the aircraft to manual control just before it fell from the sky, Chealander said.
During a Sunday briefing, Chealander described the flight's frantic(发狂似的; 疯狂的) last moments, which included a steep drop and rollercoaster-like(过山车般的) pitching(上下颠簸) and rolling.
Chealander said information from the plane's flight data recorder indicates that the plane pitched up at an angle of 31 degrees in its final moments, then pitched down at 45 degrees.
The plane rolled to the left at 46 degrees, then snapped back(迅速跳回, 很快恢复) to the right at 105 degrees — 15 degrees beyond vertical.
Radar data shows Flight 3407 fell from 1,800 feet above sea level to 1,000 feet in five seconds, he said. Passengers and crew would have experienced G-forces(地球引力, 重力) up to twice as strong as on the ground.
The plane crashed belly first on top of a house Thursday night, killing all 49 people on board and one person on the ground.
Deicing system(除冰系统) was turned on
Just before they went down in a suburban neighborhood near the Buffalo airport, the pilots discussed "significant" ice buildup on their wings and windshield(挡风玻璃). Other aircraft in the area told air traffic controllers they also experienced icing around the same time.
The Dash 8 Q400 plane operated by Colgan Air was equipped with a "stick shaker" mechanism that rattles the yolk to warn the pilot if the plane is about to lose aerodynamic lift(气动升力), a condition called a stall(失速).
When the stick shaker engaged, it would have automatically turned off the autopilot, Chealander said.
Chealander said the plane's deicing system was turned on 11 minutes after it took off from Newark, N.J., and stayed on for the entire flight. Indicator lights showed the system appeared to be working.
Investigators who examined both engines said they appeared to be working normally at the time of the crash, too.
In a December safety alert issued by the NTSB, the agency said pilots in icy conditions should turn off or limit the use of the autopilot to better "feel" changes in the handling qualities of the airplane.
Remains of 15 people recovered
By Sunday, authorities had recovered the remains of 15 people from the wreckage as crews raced to finish their work before a storm arrives later in the week.
Erie County Executive Chris Collins said recovery efforts intensified after the arrival of additional federal workers. A storm forecast for Wednesday added to the urgency.
The storm could hamper(妨碍) recovery efforts, but "the investigation will continue snow, rain or shine(风雨无阻)," said David Bissonette, the town's emergency coordinator.
Recovery crews could need as much as four days to remove the remains from the site. Chealander described the efforts as an "excavation."