What happened
On a warm morning in Manitoba, a de Havilland DHC-2 Beaver, registration C-FEYQ, departed Bissett to transport passengers and two canoes to Sasaginnigak Lake. Approximately 18 minutes into the flight, the pilot noticed the engine low fuel pressure warning light illuminate, followed by a loss of engine power.
As the aircraft was flying at a reduced altitude of 1,700 feet due to high ambient temperatures and the drag from the external canoes, the pilot had limited options. The aircraft descended through trees and struck a rocky outcrop, causing the plane to overturn. The pilot and three passengers were able to exit the wreckage without injury. The aircraft was located several hours later by an overflying plane, and the occupants were subsequently transported to a hospital.
The investigation
The investigation focused on the fuel system and the regulatory framework regarding external loads. While the pilot had switched fuel tanks and attempted to use the manual wobble pump, the engine failed to regain power. Investigators determined that the centre fuel tank had not run dry.
Examination of the wreckage revealed a kink in the main engine fuel feed line. This kink was located in an area near the oil cooler, which was operating at high capacity due to the heat. Investigators concluded that this configuration likely caused a fuel vapour lock. Additionally, the investigation found that the aircraft was using an unapproved fuel check valve that did not meet manufacturer specifications and featured a stiff return spring.
Regarding regulations, the investigation found that the operator was carrying passengers and external loads without meeting the specific conditions required by the applicable Transport Canada advisory circular. Furthermore, the investigation noted that the aircraft was not equipped with an emergency locator transmitter (ELT).