What happened
In the early morning, a pilot and one passenger departed from the Partridge Point sea plane base on the St. Marys River, near Sault Ste. Marie, Ontario. The flight, conducted in a ski-equipped Aeronca 11CC Super Chief, was intended for ice fishing on Buck Lake. While the aircraft successfully reached Buck Lake and performed a normal landing, the crew failed to return by their scheduled 1800 arrival time.
A search operation began late in the evening, though darkness initially hindered visibility. The following morning, searchers discovered a hole in the ice on the St. Marys River. Divers subsequently located the aircraft resting upright on the riverbed in approximately 12 feet of water. Both the pilot and the passenger were found outside the submerged aircraft beneath the ice. Both individuals had died from drowning and hypothermia.
The investigation
Investigators examined the aircraft and found no significant structural damage, noting only a small dent in the engine cowl and a minor bend in a wing fairing. The engine controls—including the throttle, magneto switch, and carburettor heat—were found in positions consistent with a normal landing at reduced power. Although a witness mentioned a possible issue with the aircraft's tail prior to the flight, investigators found no evidence of mechanical failure contributing to the accident.
The investigation focused on the conditions at the site of the sinking. The ice surrounding the hole was measured at only one to two inches thick, which was insufficient to support the weight of the occupants. The water temperature was approximately one degree Celsius. The fact that the seatbelts were undone and the cabin doors were open suggested the occupants had time to exit the aircraft as it submerged.
Findings
- The Aeronca 11CC Super Chief broke through a thin layer of ice on the St. Marys River during or immediately following a slow-speed landing roll.
- The extremely low water temperature of one degree Celsius, combined with the heavy, wet winter clothing worn by the occupants, significantly reduced their chances of survival after exiting the aircraft.