What happened
On July 5, 2011, a Cessna 152, registered as C-GZDR, departed Boundary Bay, British Columbia, for a training flight focused on mountain flying techniques. The aircraft was operated by the Pacific Flying Club and carried a flight instructor and a student pilot. The planned route included a flight north toward Whistler and a return trip via Harrison Lake.
During the flight, the aircraft entered a narrow valley between Mount Kessler and Winslow Peak. At approximately 1630, the aircraft struck terrain at an elevation of 2,750 feet, roughly 10 nautical miles west of Harrison Lake. The impact, occurring at a low airspeed and a steep, nose-down attitude, destroyed the aircraft. Both occupants sustained fatal injuries. An emergency locator transmitter signal was detected shortly after the crash, triggering a search by the Rescue Coordination Centre in Victoria.
The investigation
Investigators examined the wreckage and analyzed flight data, including video recovered from a smartphone carried by the student. The video, recorded 30 minutes prior to the accident, showed the aircraft crossing a ridge at an altitude of less than 100 feet above ground level, a maneuver that deviated from the school's established safety limits.
Technical analysis of the wreckage indicated the engine was producing significant power at the moment of impact, and the aircraft's attitude was consistent with a high-bank, steep-descent state. While the aircraft was found to be approximately 44 pounds over its maximum allowable takeoff weight, investigators determined that by the time of the accident, fuel consumption had brought the aircraft within permissible weight limits.
Findings
- The aircraft likely experienced an aerodynamic stall while attempting a turn within the canyon at an altitude insufficient for recovery.
- The pilots were likely flying on the left side of the valley, and an attempt to execute a right-hand turn led them toward a shadowed, steep slope, making it difficult to maintain visual references for the horizon.
- The use of a stall warning system that provides no indication of the progression toward a stall increased the risk of an inadvertent stall during maneuvering.
- Deviations from established school procedures, such as flying below the 500-foot altitude limit for ridge crossings, contributed to the accident.