BUFFALO, N.Y. - Relatives of a passenger killed when a commuter plane crashed outside Buffalo have sued Bombardier Aerospace, Continental Airlines and the flight's operators, claiming the aircraft had inadequate deicing equipment and an improperly trained crew.

The lawsuit, filed Thursday in federal court in Buffalo, appears to be the first litigation spawned by the Feb. 12 crash in Clarence. Continental Connection Flight 3407 plunged from the sky in icy weather and landed on a house, killing one occupant of the home and 49 people aboard the plane, including a Canadian man.

Investigators have not determined a cause, but ice has been mentioned as a possibility, as well as the crew's actions.

The family of crash victim Susan Wehle, of Amherst, N.Y., alleges negligence and is seeking unspecified damages. The suit names Continental Airlines, based in Houston; Pinnacle Airlines of Memphis, Tenn., and a subsidiary operating the flight, Colgan Air of Manassas, Va.; and Bombardier Aerospace, based in Montreal, which made the Dash 8 Q400 aircraft.

Bombardier refused to confirm Friday if it had been served with the lawsuit.

Company spokesman John Arnone said the company wouldn't respond to speculation.

"Our priority was and continues to be supporting the NTSB's (National Transportation Safety Board's) investigation of the accident. That is our focus," Arnone said in an e-mail to The Canadian Press.

Pinnacle and Continental declined to comment on the lawsuit.

Colgan Air previously defended its training programs and the pilot after investigators said they would look into whether the crew overreacted to a sensor indicating the plane was slowing down dangerously.