4 fatalities

Night Navigation Exercise Loss Over Lake Ontario (6739)

Lake Ontario, CanadaFlight

On January 14, 1943, an Avro 652 Anson (registration 6739) operated by Royal Canadian Air Force - RCAF was involved in an aviation accident near Lake Ontario, Canada in flight. 4 people were killed. Investigators recorded the probable cause as: The exact cause of the accident could not be determined due to the lack of recovered wreckage or other physical evidence. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 8 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 2026-08-05Data APIEditorial standards

A military aircraft departed Malton for a night exercise in marginal weather and was declared missing after failing to return. No wreckage or crew members were ever recovered.

What happened

The aircraft departed from Malton to conduct a scheduled night navigation exercise. During the mission, the flight encountered marginal weather conditions while cruising. At the conclusion of the planned exercise window, the airplane did not return to base as expected. Consequently, it was officially declared missing. Extensive search efforts failed to locate any trace of the aircraft or its occupants. It is widely believed that the plane crashed into Lake Ontario, resulting in the total loss of the airframe and all personnel on board.

Findings

The investigation concluded that the exact cause of the accident could not be determined. The combination of night operations, marginal weather, and the subsequent disappearance over a large body of water prevented a definitive causal analysis.

Probable cause

The exact cause of the accident could not be determined due to the lack of recovered wreckage or other physical evidence.