Relatives of a passenger killed when a commuter plane crashed into a house outside Buffalo have sued 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, killing one occupant of the home and all 49 people aboard the plane.

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, 55, of Amherst, N.Y., alleges negligence and wrongful death and seeks 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.

Pinnacle, Continental and Bombardier declined Friday to comment on the lawsuit, filed by aviation disaster specialists Baum, Hedlund, Aristei & Goldman of Los Angeles.

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, flying on autopilot, was slowing down dangerously.

On its Web site, Colgan calls the Q400 "a sophisticated, highly capable aircraft that is designed for cold-weather operations."

Bombardier spokesman John Arnone, who wouldn't comment directly on the litigation, noted that 230 of the Q400 planes are in use all over the world, including frequently cold areas such as Quebec and Norway.

But attorney Ronald Goldman of the firm that filed the lawsuit called the plane's deicing system antiquated. The system includes strips of rubber-like material on the wings and tail that expand to break up ice, then contract and expand again to break up new ice.

"It's a system that cannot guarantee the safety of passengers on a commercial flight," Goldman said by phone Friday. "It should never be flown in these kinds of conditions."

Goldman, also a pilot, faulted the crew for flying on autopilot, which he said concealed signs of trouble until it was too late.

The plane, which had taken off from Newark, N.J., crashed six miles from Buffalo Niagara International Airport.

The investigation by the National Transportation Safety Board is expected to take a year or more. Goldman said his firm would conduct its own investigation.

The suit seeks wrongful death damages for Wehle's sons Jonah and Jacob Mink, as well as compensation for any pain and suffering by Wehle as the plane plummeted.

"For a measurable period of time, the aircraft flew out of control, violently moved in unexpected directions, dived, rolled, inverted and subjected the passengers and contents to unusual g-forces," the lawsuit said.

Wehle, the daughter of Holocaust survivors, was a cantor at a synagogue and had performed in theater companies in New York and Chicago.