Pilots Spoke of Ice on Wings Before Deadly Crash in N.Y.
Commuter Plane Soon Fell Into 'Severe Pitch and Roll'
Saturday, February 14, 2009
The pilots of a Continental Connection commuter plane discussed icing on the plane's wings shortly before it plunged from the sky near Buffalo on Thursday night, killing all 49 people onboard and one person on the ground, authorities said yesterday.
Authorities said it is too early to tell what caused the first fatal airline crash in the United States in more than two years. But their disclosure that the pilot and co-pilot were talking about ice buildup on the wings and other parts of the plane is significant because icing has long been viewed as a serious safety problem in aviation circles. Icing caused the crash of a similar plane in similar circumstances more than 12 years ago, killing 68 people.
Authorities said everything appeared normal as Flight 3407, operated by Manassas-based Colgan Air, headed from Newark to Buffalo.
But a few minutes before the Bombardier Q400 turboprop crashed into a residential area about five miles short of the Buffalo airport at 10:20 p.m., the pilots mentioned ice building up on the windshield and wings, said Steven Chealander, a member of the National Transportation Safety Board, which is investigating the crash.
Ice disrupts airflow over wings and other surfaces and can cause a plane to lose lift, leading to a crash.
The plane's flight-data and cockpit voice recorders indicated that the plane's deicing equipment was turned on when the pilots were discussing the ice buildup, Chealander said.
About a minute before the plane hit the ground, the pilots lowered the landing gear and then deployed the plane's flaps, devices that extend from a plane's wings to help it generate more lift at lower speeds.
Suddenly, Chealander said, the plane entered "a severe pitch and roll," and the pilots unsuccessfully attempted to retract the flaps and gear before it slammed into the ground in light fog and snow. The plane struck a house, killing one occupant, about five miles from Buffalo Niagara International Airport.
Safety experts said that preliminary descriptions of the pilot's conversations and the violent "pitch and roll" indicated that icing probably played a role in the crash.
Still, they said, investigators will have to figure out whether the plane's deicing equipment was working properly and was activated in time or whether there was too much ice for the system to handle.
The plane flew through icing conditions reported by other pilots for about 10 minutes as it descended toward the airport.
"What remains to be seen: Is there some other malfunction to the deicing system or other systems?" said William R. Voss, president of the Flight Safety Foundation. "That's a fancy way of saying we don't know why the airplane crashed yet."