Accident Details
On 10 October 2016, at approximately 0820 Pacific Daylight Time, a privately operated de Havilland DHC-2 Beaver aircraft on amphibious floats (registration C-GEWG, serial number 842) departed from Vanderhoof Airport, British Columbia, on a day visual flight rules flight to Laidman Lake, British Columbia. The pilot and four passengers were on board. Approximately 24 minutes into the flight, the aircraft struck terrain about 11 nautical miles east of Laidman Lake. The 406 MHz emergency locator transmitter (ELT) activated on impact, and its distress signal was detected by the Cospas-Sarsat satellite system. The Joint Rescue Coordination Centre Victoria initiated a search-and-rescue operation. One passenger was able to call 911 using a cell phone. The pilot was fatally injured, and two passengers were seriously injured; the other two passengers sustained minor injuries. The aircraft was substantially damaged, and there was no post-impact fire.
Investigation Findings
The investigation identified several findings as to causes and contributing factors: 1. As the aircraft approached the mountain ridge, the high overcast ceiling and uniform snow-covered vegetation were conducive to optical illusions associated with flight in mountainous terrain. These illusions likely contributed to the pilot’s misjudgment of the proximity of the terrain, inadvertent adoption of an increasingly nose-up attitude, and non-detection of declining airspeed before banking the aircraft to turn away from the hillside. 2. As the angle of bank increased during the turn, the stall speed also increased and the aircraft entered an accelerated stall. 3. The aircraft’s out-of-limit weight-and-balance condition increased its stall speed and degraded its climb performance, stability, and slow-flight characteristics. As a result, its condition, combined with the aircraft’s low altitude, likely prevented the pilot from regaining control before the collision. 4. The absence of a stall warning system deprived the pilot of the last line of defence against an aerodynamic stall and subsequent loss of control. 5. The forward shifting of unsecured cargo and partial detachment of the rear seats during the impact resulted in injuries to the passengers. 6. During the impact sequence, the load on the pilot’s lap-belt attachment points transferred to the seat-attachment points, which failed in overload, causing the seat to move forward and fatally injuring the pilot.
Findings as to risk included:
- If pilots do not obtain quality sleep during the rest period prior to flying, there is a risk that they will operate an aircraft while fatigued, which could degrade pilot performance.
- If cargo is not secured, there is a risk that it will shift forward during an impact or turbulence and injure passengers or crew.
Other findings noted that because the aircraft was equipped with a 406 MHz ELT that transmitted an alert message to the Cospas-Sarsat satellites system in combination with a homing signal on 121.5 MHz, the Joint Rescue Coordination Centre aircraft was able to locate the wreckage and occupants in a timely manner.