U.S. safety investigators have issued an urgent recommendation that Canadian aerospace giant Bombardier Inc. correct a problem that has caused seven fires aboard its popular jetliners.

"The potential consequences of these fires can be catastrophic," Mark Rosenker, acting chairman of the U.S. National Transportation Safety Board, told Reuters.

The safety board's recommendation affects the CRJ-200, one of the most popular airliners in the United States and one of Bombardier's biggest money makers in recent years.

Regional Jets assembled at the Bombardier plant in Montreal have come under fire by U.S. safety officials. (Ryan Remiorz/CP photo)

The 50-seat Regional Jets are extensively used by Air Canada for its feeder and low-volume routes.

The fires were caused by short circuits in the aircraft's instrument wiring system, the safety board concluded after a long investigation.

Nobody has been injured, but four of the fires knocked out electronic cockpit displays, preventing the crews from using their main flight instruments, at least temporarily.

The short circuits were blamed on water that apparently seeped through the floor of the aircraft cabin and came into contact with electrical wires under the floor.

The water came from rain and snow tracked into the plane when passengers boarded. Rain also came into the cabin when the door was left open in rainstorms.

The U.S. government can ground the aircraft if Bombardier does not comply with the recommendation.

Bert Cruickshank, spokesman for Montreal-based Bombardier, told the Associated Press the company is looking at ways to prevent the fires and has already told airlines to implement maintenance procedures to make sure the cockpit displays always work.

"We've been involved and assisted and co-operated fully with NTSB, FAA and Transport Canada in determining the causes of these incidents," Cruickshank said.