What happened
A de Havilland DHC-2 seaplane, registration C-GZBQ, departed Big Trout Lake, Ontario, for Geraldton, Ontario, carrying a pilot and an aircraft maintenance engineer. During the flight, the pilot diverted to Pickle Lake due to deteriorating weather conditions. While descending toward the lake at approximately 300 feet, the engine abruptly lost power.
The pilot attempted several restart procedures, including switching between fuel tanks and operating the wobble pump, but the engine failed to restart. The pilot executed a forced landing on a nearby narrow river at speeds between 40 and 45 mph. Following the impact with the riverbank, the aircraft's left wingtip struck trees, causing the aircraft to yaw 180 degrees and strike the bank again, which broke off the floats and struts. The right wing and elevator also sustained damage. Both occupants, wearing shoulder harnesses, escaped uninjured.
The investigation
The investigation focused on the engine failure and the condition of the fuel system. Investigators examined the engine, propeller, and airframe, finding no structural defects or mechanical issues with the engine controls or magnetos. However, fuel samples taken from the fuel line and the delivery line fuel strainer revealed rusty brown water with very little fuel present.
Prior to the flight, the aircraft had been refuelled at Big Trout Lake using fuel transferred from drums into the aircraft via a hand-operated wobble pump. While the wobble pump had a particulate filter, it was not designed to remove water. The investigation also noted that the aircraft had been beached in a nose-level attitude rather than the standard nose-up position, which may have prevented water from settling into the tank sumps for proper drainage during pre-flight checks.
Findings
- The engine ceased operation because the fuel system contained a significant amount of water.
- The water contamination likely originated from the drums used during the refuelling process.
- A suitable filter or water separator was not utilized during the transfer of fuel from the drums to the aircraft.
- The nose-level positioning of the aircraft on the beach, combined with freezing temperatures, likely prevented the pilot from detecting the water during pre-flight sump drains.