An inexperienced refueling technician and failure by the pilots to observe and confirm that the correct fuel had been used were among the factors that led to the Sept. 15, 2015 crash of a Keystone Air Service plane shortly after taking off from the Thompson airport, says the Transportation Safety Board of Canada (TSB).
The TSB’s aviation investigation report into the crash, which took place in the woods adjacent to Highway 391 after the pilot aborted an attempted emergency landing onto the road because of vehicle traffic, was released Sept. 6. Refuelling with jet fuel rather than aviation gasoline was confirmed as the cause of the Piper PA31-350’s engine failure within a couple of weeks of the crash, which resulted in various injuries to the six passengers and two pilots on board.
The flight left Thomson Airport for Winnipeg shortly after 6 p.m. Sept. 15 and began having engine trouble shortly after takeoff, at which point the pilot informed the Thompson Flight Service Station that it was returning to the runway, though it ended up crashing about 700 metres from the threshold of Runway 06.
The plane, which had departed from Winnipeg the morning of the crash, had been scheduled to fly from Oxford House to Pikwitonei but weather conditions forced the cancellation of the last stop and it stopped in Thompson to refuel for the return flight to Winnipeg.
The TSB investigation revealed that the aircraft refuelling technician who refuelled the Keystone flight, who had been working for Mara-Tech Aviation Fuels Ltd. for a little over a month, had fuelled another aircraft with jet fuel before the Keystone flight arrived. The technician then parked the jet fuel truck outside the Mara-Tech office and left it running. When the Keystone flight arrived, the technician left the building, got back in the truck and drove it out to where the Keystone aircraft had landed. The pilot-in-command of the flight had intended to relay the fuel requirements to the technician, but the second-in-command noticed that the technician was having trouble determining which fuel filler openings were for the main tanks. The second-in-command showed the technician where they were and asked for both main tanks to be filled and for 80 litres to be put in each auxiliary tank. Neither pilot noticed that the truck was a jet fuel truck. When the technician couldn’t get the flared fuel filler nozzle used for most planes requiring jet fuel to fit, he switched to a narrower nozzle. Some planes requiring jet fuel cannot be refuelled with the flared nozzle, which was introduced in 1985 to help prevent refuelling with the wrong type of fuel. The technician did not notice the notice on the side of the aircraft specifying that aviation gasoline was the correct fuel.
Prior to departure, the pilot-in-command returned to the fuel dealer’s building to retrieve the fuel slip but no one was there and the door from the ground-side of the airport was locked so the pilot could not go through it. Neither the pilot nor the second-in-command tried the air-side door and they performed an abbreviated safety check before taking off that did not include sampling of the fuel sumps, which Keystone pilots normally did only before the first flight of the day, the investigation found. This may not have indicated that the wrong type of fuel had been used anyway because about a third of the fuel in the tank was still aviation gasoline, the TSB determined.
Following the crash, Kesytone’s operator certificate was suspended by Transport Canada on Oct. 9. This was the result of a post-accident inspection that revealed safety concerns. In December of last year, Transport Canada cancelled Keystone’s air operator certificate, citing the public interest and the company’s aviation safety record.