What happened
A Rusty Myers Flying Service Beech D18S, registration C-FBGO, departed Fort Frances, Ontario, for a visual flight rules (VFR) trip to Granite Lake with one pilot and four passengers. During the flight, near Ignace, the aircraft encountered heavy rain and declining visibility. The pilot attempted to navigate through the deteriorating weather at a low altitude, seeking a clear horizon beneath the clouds.
While maneuvering, the pilot reported a partial loss of power in the engines. The pilot attempted to use carburettor heat, but the engines could not regain sufficient power to maintain altitude. The aircraft subsequently struck trees, traveling approximately 500 feet through the forest. The impact tore off the left wing and triggered a fuel-fed fire. All five occupants survived the crash with minor injuries, though one passenger sustained burns. The crew was rescued by helicopter approximately one hour after the accident.
The investigation
The investigation focused on the engine failure and the environmental conditions. Investigators examined the aircraft's fuel composition, noting it was a mixture of 25% 100 low-lead aviation gasoline and 75% automotive fuel (MOGAS). The investigation also reviewed the pilot's weather-navigation strategy and the company's established procedures for managing icing risks.
Findings
- The pilot continued the flight into adverse weather conditions at a low altitude.
- The pilot believed weather would improve based on radio communications with another aircraft that was ahead on a different route.
- The engines experienced a partial power loss, likely caused by carburettor icing.
- The use of MOGAS increased the aircraft's susceptibility to ice formation.
- Ambient temperature and dew point conditions were highly conducive to serious carburettor icing.
- The pilot's method of applying carburettor heat differed from the company's recommended practice of applying heat proactively before entering precipitation.
- There was insufficient time to clear the ice and recover altitude before the aircraft struck the trees.
- Refraction from rain on the windscreen may have caused the pilot to misjudge the aircraft's actual altitude.
- The placement of the first aid kit and the obstruction of the survival kit by baggage hindered the rapid retrieval of emergency equipment during the evacuation.