Efforts have begun in central Ontario to recover a military plane that crashed in Lake Muskoka nearly 74 years ago with two crew on board.

Northrop Nomad 3521 collided in-flight with another Nomad aircraft on Dec. 13, 1940 while the planes were searching for a fellow airman who went down during Second World War training at what is now Canadian Forces Base Borden.

The bodies of two airmen on the second Nomad were found shortly after, while the remains of the pair on 3521 — Flight Lt. Peter Campbell, 24, and Leading Aircraftsman Theodore Bates, 27 — were recovered by a Royal Canadian Navy dive team in October 2012.

The wreckage of the two-seater light attack bomber used for training was discovered in 2010 along with the men's personal effects, and the Royal Canadian Air Force is now leading the effort to raise the aircraft from the lakebed.

National Defence says the recovery operation is expected to last approximately 10 days and will be done with "extreme care."

It says the wreckage will be turned over to the National Air Force Museum of Canada.