Debrief: Get Your Head in the Game: Three R44s fuelled with Jet Fuel!

This article is based on an Aviation Safety Advisory issued by the Transportation Safety Board of Canada (TSB), and TSB (Class 5) File A11Q0036.

On March 1, 2011, a privately owned Robinson R44 II helicopter with two people on board was on a VFR flight from Port-Menier, Que., to Jean-Lesage International Airport in Québec City, with a stopover at the Forestville airport, Que., for refuelling. The R44 II was accompanied by two other Robinson R44 IIs. During the stopover in Forestville, the three aircraft were erroneously refuelled with jet fuel (Jet A-1) rather than the required Aviation Gasoline (AVGAS) 100LL. During its initial climb, the R44 II lost engine power and the pilot made a forced landing in a residential neighbourhood in Forestville. Both people on board sustained minor injuries and were taken to hospital. The aircraft did not catch fire but it was heavily damaged. The two other aircraft landed near the same site and sustained no damage, although both necessitated an engine check.

When fuelling, the pilots were present and were helping the refueller, without ever noticing that the pump being used was for fuel type Jet A-1. The three pilots then each signed their individual fuel vouchers, which clearly specified that Jet A-1 fuel had been pumped into the fuel tanks. There are instructions on all three aircraft, by the tanks, outlining the maximum capacity of the tank and the type of fuel to use. These measures were not enough to prevent the error. It should be noted that the aircraft refueller was a new employee, who had only been there since December 2010, and his training was limited.

The fuel nozzle for Jet A-1 fuel in this instance had a 1 in. diameter, which is why the refueller was able to insert it into the AVGAS fuel filler opening of the three R44s.

While there are no fuel nozzle dimension standards for aircraft refuelling at Canadian airports, there are airworthiness standards for obtaining type approval and changes to type certificates for normal, utility, aerobatic, and commuter type aeroplanes. Section 523.973 of the Canadian Aviation Regulations (CARs) specifies that for aeroplanes with engines requiring gasoline as the only permissible fuel, the inside diameter of the fuel filler opening must be no larger than 2.36 in., whereas for aeroplanes with turbine engines, the inside diameter of the fuel filler opening must be no smaller than 2.95 in. However, there is no standard for helicopters.

During the initial installation of equipment at aerodromes and airports, several gas and fuel providers equip refuelling stations with fuel nozzles of varying dimensions to avoid errors of this nature. Normally, the nozzles used for AVGAS have a 1 in. diameter, while the refuelling nozzles for Jet A-1 have a minimum 3 in. diameter. That way, even if the refueller makes a mistake in the selection of the appropriate fuel, the 3 in. refuelling nozzle cannot be inserted into the smaller fuel filler openings, which the majority of piston engine aeroplanes are equipped with.

The AVGAS-running Robinson R44 II is equipped with a 1.5 in. fuel filler opening, while the turbine-equipped Bell 206 helicopter has a fuel filler opening of 3.25 in. However, the Aerospatiale AS350 helicopter, which also runs on jet fuel, has a 2.28 in. fuel filler opening. Therefore in order to refuel an AS350 with Jet A-1, the 3 in. nozzle has to be modified or changed to a smaller nozzle. Considering that there are over 450 AS350 aircraft registered in Canada, it is feasible that several refuelling stations in Canada had to modify the fuel nozzles, just like at the Forestville airport, in order to accommodate these helicopters.

Similar events have occurred in the last few years, not only with helicopters but with aeroplanes equipped with piston engines. This latest event shows that despite the precautionary measures in place, it is still possible that the wrong fuel type will be pumped into aircraft fuel tanks. Fuel providers and refuelling stations are therefore reminded of the risks associated with fuel nozzle sizes and the importance of training refuellers accordingly. In closing, we also remind pilots to pay close attention to the fuelling of their aircraft with the proper fuel.

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