The fuel load was not considered to be a factor in the pilot's decision to fly the trip under VFR rather than IFR. Fuel was readily available at Yellowknife, and there was adequate time between the arrival from Fort Simpson and the departure for Lutsel K'e to bring the fuel quantity to IFR requirements under the supervision of dispatch personnel.
Although the pilot had gained experience in an IFR environment during his flying as a copilot in multiengine aircraft, he had limited experience in single-pilot IFR operations. This may have led to reluctance to file an IFR flight plan on the accident flight, and the decision to remain visual in marginal VFR weather conditions. The route lay mostly in uncontrolled airspace, and when flight visibility deteriorated, the pilot had the option of climbing without ATC clearance to a safe altitude, and conducting an instrument approach at Lutsel K'e. The pilot apparently was willing to fly in cloud as indicated by the earlier flight from Fort Simpson to Yellowknife, albeit on a VFR flight plan in controlled airspace.
Decision-making and THC Effects
On the day of the accident, aspects of the pilot's planning, flying technique and decision-making were inconsistent with regulatory and administrative requirements, the company operations manual policy and safe flying practices. These included VFR flight in marginal visual weather conditions, flight in IMC on a VFR flight plan, and overwater flight beyond gliding distance of land. The quantity of psychoactive components in the pilot's system is considered to have been sufficient to result in impairment of cognitive processes. This would likely have had an effect on planning and conduct of the accident flight. It is possible that the pilot, under the influence of cannabis, avoided the higher workload of IFR flight in IMC, choosing to remain visual for the trip to Lutsel K'e.
Overwater Flight Risk
The company did not provide personal floatation devices in the land-plane fleet, and management expected single-engine aircraft to remain within gliding distance of land at all times. The pilot was familiar with the route, and given the low cloud en route and the current weather at Lutsel K'e, it is likely that a diversion to the south to remain within gliding distance of land would have to be made well before arriving at the shoreline near the accident location. The direct flight track flown toward Lutsel K'e suggests that, after crossing the Pehtei Peninsula, the pilot was prepared to overfly 11 nm of open water at low level, increasing the risk to the aircraft and its occupants. Overflight of Great Slave Lake on the earlier flight from Fort Simpson to Yellowknife indicated a willingness on the part of the pilot to accept that risk.
Rather than issue a “probable cause,” Canada's Transportation Safety Board issues “Findings as to Causes and Contributing Factors,” “Findings as to Risk” and “Safety Actions.”
In this case, the TSB issued the following:
Findings as to Causes and Contributing Factors:
(1) The aircraft was flown at low altitude into an area of low forward visibility during a day VFR flight, which prevented the pilot from seeing and avoiding terrain.
(2) The concentrations of cannabinoids were sufficient to have caused impairment in pilot performance and decision-making on the accident flight.