What happened
On July 14, 2008, a float-equipped de Havilland DHC-2 (registration C-FPQC) departed from Crossroads Lake, Newfoundland and Labrador, carrying a pilot and six passengers. Shortly after takeoff, while the aircraft was climbing at approximately 350 feet, the engine suffered a sudden failure.
In response to the loss of power, the pilot attempted a left turn to locate a landing site. During this maneuver, the aircraft's airspeed dropped, leading to an aerodynamic stall at an altitude that precluded recovery. The aircraft subsequently struck a bog, resulting in five serious injuries and two minor injuries. The aircraft sustained substantial damage, though no fire occurred following the impact.
The investigation
The investigation focused on the mechanical state of the engine and the pilot's actions during the emergency. Investigators examined the engine's recent overhaul history and analyzed data from a recovered Garmin GPS to reconstruct the flight path.
Technical examination of the engine revealed that during a recent overhaul, the necessary linkpin plugs had not been installed. Over the 90 flight hours following the overhaul, this omission led to reduced oil pressure at the master rod bearing and crankpin interface. The resulting friction and heat caused accelerated wear and material smearing, ultimately leading to a catastrophic loss of lubrication and engine failure.
Additionally, investigators reviewed the pilot's decision-making during the forced landing. While the pilot sought a more suitable landing area, the turn initiated caused the aircraft to enter a stall. The investigation also noted that the pilot was not wearing a shoulder harness, which likely contributed to the severity of the injuries.
Findings
- The primary cause of the engine failure was the omission of linkpin plugs during a recent engine overhaul, which caused inadequate lubrication to the linkpin bushings.
- The aircraft entered an unrecoverable aerodynamic stall during the pilot's attempt to maneuver for a forced landing.
- The failure to use a shoulder harness increased the risk and severity of the injuries sustained by the occupants.