What happened
On a night flight departing from Rainbow Lake, Alberta, an Airco Aircraft Charters Piper PA-31-350 Chieftain collided with trees and terrain approximately 3,000 feet from the end of the runway. The aircraft, which was operating a domestic public charter for Northern Sky Aviation, had been flying a multi-leg route including Edmonton and High Level. Shortly after lifting off from runway 27, the aircraft struck the tops of trees before descending to the ground.
Despite the impact, the cockpit and cabin remained intact, and all nine occupants escaped with minor injuries. The accident occurred in darkness, with no moon and minimal ambient light. Following the crash, a passenger used a cell phone to alert emergency services, leading to a successful rescue by ground and aerial teams despite freezing temperatures and deep snow.
The investigation
Investigators examined the aircraft's weight and balance, the pilot's performance, and the operational procedures of both Airco Aircraft Charters and Northern Sky Aviation. The investigation established that the aircraft was significantly overweight at the time of departure. While the aircraft was modified to allow for a higher takeoff weight, calculations indicated it exceeded its maximum allowable limit by approximately 315 pounds, with the center of gravity positioned beyond the aft limit.
Technical examinations of the engines and flight controls revealed no mechanical failures. The investigation also looked into the role of a Northern Sky Aviation representative who was on board as a customer service agent but held no formal cockpit duties. Furthermore, the investigation reviewed the pilot's night flight techniques and the impact of the dark, featureless terrain during the climb.
Findings
- The aircraft was overweight at takeoff, which reduced its climb performance and increased the required takeoff distance.
- The pilot failed to maintain a positive rate of climb, instead focusing on reaching a specific target airspeed (blue line speed).
- The pilot was likely influenced by the somatogravic illusion, a false sensation of climbing that can lead a pilot to inadvertently pitch the nose down in dark conditions.
- Crew resource mismanagement occurred due to the ambiguous role of the company representative, whose presence did not contribute to flight safety.
- The decision to depart from runway 27 was influenced by a desire to avoid a frost heave on runway 09, leading to a departure into rising terrain and darkness.
- Communication gaps between the two companies meant the pilot was unaware that the company representative could have been removed to reduce the aircraft's weight.