A woman wipes away tears during a community prayer service for the plane crash victims in Williamsville, New York. (AFP)

Washington, Feb. 14: 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 US in more than two years. But their disclosure that the pilot and co-pilot were talking about ice build-up 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 8km short of the Buffalo airport at 10.20pm (local time), 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 build-up, 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.