Background
On the day of the accident, a de Havilland DHC-2 Mk.1 Beaver floatplane (registration C-FGBF, serial number 168) operated by Cochrane Air Service departed Lillabelle Lake, Ontario, at approximately 1105 for a flight to Nettogami Lake, Ontario, with three passengers and cargo. After that flight, the aircraft flew empty to Edgar Lake, Ontario, to pick up two passengers and 300 pounds of cargo, then departed Edgar Lake at approximately 1252 for the return flight to Lillabelle Lake. Due to a strong headwind, the 77-nautical-mile flight took about 76 minutes.
Accident Sequence
Approaching Lillabelle Lake, the pilot contacted company operations and was advised that winds were very strong and that after landing the aircraft should taxi to the dock on the western shore. The pilot chose to make a southwest approach into the wind over the narrow northern portion of the lake, which provides approximately 1800 feet of landing distance. The western shore on the windward side of the approach slopes upward and is lined with large trees. The aircraft encountered very gusty conditions during the approach and, after entering the flare, the pilot was unable to settle onto the water due to wind gusts. About halfway across the lake, the pilot aborted the landing and applied full power. Within seconds, the aircraft rolled quickly to the left and struck the water in a partially inverted attitude, first with the left wing, then the cockpit and right wing. The fuselage submerged, and the aircraft came to rest inverted on the muddy lake bottom, partially suspended by the undamaged floats. The emergency locator transmitter activated on impact at 1408 Eastern Daylight Time.
Rescue and Injuries
Company and maintenance personnel who witnessed the accident attempted to reach the scene but were hindered by wind and rough waters. The rescue boat initially submerged and departed a few minutes later. Responders found the front-seat passenger, who had egressed the aircraft and was resting on a float, seriously injured. They opened the left main door but could not locate others due to murky, gasoline-covered water. The survivor was transported to hospital. The pilot and rear-seat passenger drowned and were not able to exit the aircraft.
Investigation Findings
The investigation determined that the aircraft was maintained in accordance with regulations, and the company operated within Canadian Aviation Regulations and its own operations manual. The analysis focused on the pilot, circumstances leading to the water impact, and systemic safety issues in the floatplane industry.
Causes and Contributing Factors
- On the windward side of the landing surface, significant mechanical turbulence and wind shear were caused by strong gusty winds passing over surface obstructions.
- During the attempted overshoot, rapid application of full power caused the aircraft to yaw left, and a left roll developed. Combined with a high angle of attack and low airspeed, the aircraft likely stalled. The altitude available to regain control before striking the water was insufficient.
- The pilot survived the impact but was unable to exit the aircraft, possibly due to difficulties finding or opening an exit, and drowned.
- The rear-seat passenger did not have a shoulder harness and suffered a critical head injury from striking the pilot's seat; this passenger did not exit and drowned.
Risk Findings
- Without a full passenger safety briefing, passengers may not use available safety equipment or perform emergency functions effectively.
- Not wearing a shoulder harness increases the risk of injury or death.
- Absence of a stall warning system increases the risk of an impending stall going undetected.
- Commercial seaplane pilots without underwater egress training are at increased risk of being unable to exit after a survivable water impact.
Safety Action
Cochrane Air Service began providing a printed graphic area forecast to pilots each morning, requiring pilots to sign and verify conditions are suitable.
The Transportation Safety Board recommended that Transport Canada require underwater egress training for all flight crews engaged in commercial seaplane operations (recommendation A13-02). The board also noted that a significant portion of the commercial floatplane fleet lacks shoulder harnesses for passenger seats, and that the use of three-point restraints reduces injury risk.
Probable Cause
The aircraft stalled during an attempted overshoot due to a combination of mechanical turbulence, wind shear, a high angle of attack, and low airspeed, leading to loss of control.