Experts looking into February's commuter plane crash near Buffalo, New York are raising the possibility that a better warning system might have prevented the disaster.

An expert in cockpit distractions told a hearing in Washington that an audible warning would have alerted the crew that the plane was traveling at dangerously low speeds.

A transcript of the cockpit conversation in the flight's final minutes shows the pilot and co-pilot discussing their careers and concerns about flying in icy conditions.

They apparently didn't realize the danger until a stall warning went off. And National Transportation Safety Board member Debbie Hersman says that warning came too late. She says the crew "went from complacency to catastrophe in 20 seconds."

The board hasn't concluded what initially caused the plane to decelerate.

The crash killed all 49 people on the plane and one on the ground.