What happened
On 18 July 2011, an Air Tamarac Inc. Cessna A185E floatplane, registered C-FZNK, departed the La Tuque, Quebec, seaplane base for a short sightseeing excursion. The aircraft was carrying the pilot and four passengers. Approximately 12 minutes into the flight, while cruising at 160 and 1600 feet above sea level, the engine stopped functioning and the propeller began to windmilling.
In an attempt to manage the emergency, the pilot tried various engine restart procedures and attempted to contact the company via radio, but received no response. Seeking a safe landing site, the pilot targeted the Bostonnais River. During the descent, the pilot executed a sharp left turn to avoid trees along the riverbank. This maneuver caused the aircraft to stall and nose-dive into the water. The impact caused the aircraft to tumble and come to rest inverted in the river.
Local residents arrived quickly to assist with the rescue. Of the five people on board, the pilot and three passengers survived, but one passenger died due to drowning.
The investigation
The investigation focused on the cause of the engine failure, the pilot's emergency management, and the circumstances of the occupants' evacuation. Investigators examined the fuel system and the aircraft's maintenance history. While the pilot was qualified and familiar with the aircraft, the investigation looked into the reliability of the fuel gauges and the adequacy of the safety briefing provided to passengers.
Findings
- The engine failure was caused by momentary fuel starvation in the left fuel tank.
- The pilot had estimated the fuel levels rather than using a dipstick before this specific flight, leading to an inaccurate understanding of the remaining fuel.
- The fuel quantity indicators on this aircraft type are known to be unreliable at low levels.
- During the emergency, the pilot failed to activate the auxiliary electric fuel pump, which prevented a successful engine restart.
- The pilot's attempt to maneuver around terrain led to an aerodynamic stall at an altitude too low for recovery.
- The safety briefing was incomplete; it did not cover the use of personal flotation devices (PFDs) during a capsized aircraft scenario, nor did it direct passengers to safety cards.
- The lack of jettisonable windows and the difficulty of unlocking the door contributed to the challenges of evacuating the submerged, inverted cabin.
Safety action
Following the incident, Air Tamarac Inc. updated its operations manual to mandate the wearing of inflatable PFDs and to require that safety briefings be conducted before engine start-up. The company also implemented enhanced emergency egress training for pilots. Additionally, the company has moved toward installing jettisonable windows on its aircraft to improve exit capabilities during water landings.