LONGUE-POINTE-DE-MINGAN, Quebec — Canadian divers have stumbled upon what they believe is the wreckage of a U.S. Army air force amphibious plane that went down in the St. Lawrence River in 1942.

Nine people were aboard the PBY-5A Catalina, which was based at Presque Isle, Maine.

The government divers, who work for Parks Canada, announced Thursday they came across the wreck while doing routine work near the village of Longue-Pointe-de-Mingan in eastern Quebec. It has not yet been confirmed whether it is the lost plane.

The U.S. military considers the potential discovery a major find.

“It’s tremendously important because of the history, of the cooperation between the United States and Canada, not only during that time but up to the present day and in the future,” Joe Breen, the defense attache to the U.S. Embassy in Canada, said Thursday.

According to the War Department, which later became the U.S. Department of Defense, the plane had completed the first leg of a routine flight and was taking off for the return trip to base when it capsized in rough weather in the eastern Gulf of Saint Lawrence on Nov. 2, 1942.

Four crew members survived. Five others died inside the aircraft. Their bodies have yet to be recovered.

Surviving were: retired Capt. John B. Holmberg, Chicago; Tech. Sgt. George C. Peterson, Welch, La.; Cpl. Robert L. Ashley, Riverside, Calif.; and Pvt. James E. Click, Lexington, Ky.

Missing were: Lt. Col. Harry J. Zimmerman, Bayside, Long Island, N.Y.; Capt. Carney Lee Dowlen, Dallas; Sgt. Charles O. Richardson, Charlevoix, Mich.; Pvt. Erwin G. Austin, Monroe, Maine; and Pvt. Peter J. Cuzins, Cincinnati.

Recent sonar data indicate the seaplane is in good condition and that human remains may be found.

Parks Canada said Canada and the United States will work together to salvage the wreckage and to explore the possibility of eventually recovering the remains of the missing crew members.