Trans-Canada Air Lines flight 9, a Canadair C-4 North Star, crashed following a mid-air collision with an RCAF Harvard near Moose Jaw, SK, Canada, killing all 35 occupants, the pilot of the Harvard and one person on the ground. The Canadair C-4 was on a flight to Vancouver and had been cleared on an IFR flightplan flying at 6000 feet on Green Airway 1 between Winnipeg and Calgary, which was the first intermediate stop. At 09:57 an RCAF Harvard Mk. II took off from RCAF Station Moose Jaw for a navigation cross-country exercise. The Harvard was climbing to 9000 feet, crossed the Airway at 6000 feet and collided with the C-4. A large portion of the wreckage fell on a house which was destroyed by fire, killing the only occupant. The Harvard pilot and all 35 occupants of the C-4 where also killed. PROBABLE CAUSE: “1) Failure on the part of the pilots of both aircraft to maintain a proper lookout, the onus of responsibility for keeping out of the way being with the Harvard aircraft as it had the other on its own right side. 2) The Harvard aircraft in crossing the airway climbed through altitudes normally used by aircraft flying along the airway. 3) The Board up to the present has been unable to determine whether the window post on the left side of the Canadair C4-1 aircraft hid the Harvard aircraft from view, but there are indications that this was possible.”