With a crew of two and six passengers, a Piper PA-31-350 Navajo Chieftain was scheduled to operate a charter flight from Thompson Airport to Winnipeg Airport, both in the province of Manitoba, Canada. As part of the flight preparation, the aircraft needed to be refuelled.
The aircraft in its final position (© TSB)
The refueler received the refuelling request from the copilot and proceeded to refuel the aircraft. However, the nozzle on the refuelling hose would not fit in the aircraft's fuel filler opening. The refueller decided to change the nozzle on the refuelling hose to one that fit the filler opening. Subsequently, the aircraft was refuelled with 406 litres of Jet-A1. The fuel slip was not handed over to the crew. When the crew went to retrieve it from the refueller's office, it was closed.
Typical fuel nozzles, left for Jet Fuel, right for AVGas (© TSB)
With the passengers onboard the preflight checks were completed (Fuel tanks were not sampled) and at 18.13 lt (local time) the aircraft engines were started. After a short taxi, the aircraft started its take-off roll at 18.17 with the copilot as pilot flying (PF). The initial take-off was normal with the engine apparently operating normally. After rotation, the aircraft was not accelerating or climbing as expected, and the manifold pressure of both engines had decreased. The crew selected the landing gear up and retracted the flaps. The SIC initiated a gentle turn to the right and concentrated on maintaining airspeed while the PIC attempted to troubleshoot the power loss.
At 18.19 lt the PM (the captain) called ATC to inform them about their intention to return to the field for a landing on Runway 06.
When the aircraft was on the downwind leg the power output of both engines decreased more and more. It became impossible to maintain altitude and a forced landing became the only option for the crew. The gear was selected down, and the initial idea of landing on Highway 391 was abandoned due to traffic. The captain took control of the aircraft and turned the aircraft to a partly wooded area where a successful forced landing was completed. At 18 lt the Emergency Locator Transmitter activated. ATC failed to get radio contact with the aircraft. The occupants sustained varying serious injuries but were able to assist each other and exit the aircraft.
The aircraft in its final position (© TSB)
The aircraft sustained extensive damage to its fuselage, wings, landing gear and engines. The Transportation Safety Board of Canada (TSB) was alerted and an investigation was launched. After investigating the TSB published its report on the 6th of September 2016, and in that report identified the following findings as to the cause and contributing factors;
Delivery of the incorrect type of aircraft fuel caused a loss of power from both engines, necessitating a forced landing.
The fuelling operation was not adequately supervised by the flight crew.
A reduced-diameter spout was installed that enabled the delivery of Jet-A1 fuel into the AVGAS fuel filler openings.
The fuel slip indicating that Jet-A1 fuel had been delivered was not available for scrutiny by the crew
Two findings as to risk were also identified;
If administrative and physical defences against errors in aviation fuel operations are circumvented or disabled, there is a risk that the incorrect type of fuel will be delivered.
If a reduced-diameter spout is available to accommodate non-standard fuel filler openings, there is an increased risk that Jet-A1 fuel can be dispensed into an aircraft that requires AVGAS.
Safety actions were taken by the operator and Transport Canada, they can be found in the investigation report (which was used as the basis for this blog) by clicking on the .pdf file below;
The aircraft radar track (Source: Google Earth, with annotations by TSB)
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