What happened
On a scheduled day flight under visual flight rules, a turbine-powered de Havilland DHC-3 Otter, registration C-GMCW, departed Mayo, Yukon, destined for the Rackla Airstrip. The aircraft was performing mineral exploration support, transporting fuel barrels and construction timber. Approximately 19 minutes into the flight, an emergency locator transmitter alert was triggered.
Search efforts by a commercial helicopter eventually located the wreckage on a remote, snow-covered hillside roughly 38 nautical miles northeast of Mayo. The aircraft had suffered a catastful in-flight breakup, with the wings, flight controls, and empennage separating from the fuselage during flight. The pilot, who was the sole occupant, sustained fatal injuries. There was no post-impact fire, though the rupture of fuel tanks released approximately 770 litres of jet fuel into the environment.
The investigation
The investigation examined the pilot's operational history, flight duty records, and the mechanical state of the aircraft. It was established that the pilot had been flying extensively for the company, often completing numerous trips per day. Investigators analyzed GPS data from the aircraft, which revealed significant discrepancies between actual flight times and the times recorded in the aircraft's journey logs.
Furthermore, the investigation reviewed the operator's methods for tracking crew duty periods. While the company had a system for monitoring flight and duty times, the investigation found that the actual flight duty time recorded by the pilot exceeded the limits required by the company's specific operating specifications, as the necessary extended rest periods had not been implemented when flight times exceeded certain thresholds.
Findings
- The aircraft experienced a structural failure in flight involving the separation of the wings, empennage, and all flight controls.
- The pilot's actual flight duty times had exceeded the limits required by the operator's specific regulations, as the necessary extensions to minimum rest periods were not provided when daily flight durations exceeded eight hours.
- There were inaccuracies in the aircraft journey logs, where recorded air times were significantly lower than the actual times captured by GPS data.
- The pilot's remuneration was based on a per-mile-flown basis, a practice noted in industry reports as a potential pressure on operational decision-making.