Delivering the incorrect type of fuel into an aircraft is known as misfuelling. This risk exists because aviation aircraft are generally fuelled via the over-wing method using a hand held trigger nozzle.
The consequences of a misfuelling can be devastating, especially when jet fuel is delivered into piston-powered aircraft, which require avgas. The blend in the aircraft's fuel tanks that results from misfuelling can severely affect engine performance and lead to total engine failure – probably just after the aircraft has taken off.
This is because jet fuel (kerosene) does not burn particularly well in an internal combustion engine. It is like putting diesel into your petrol-operated car.
When ordering fuel, you should specify the type of fuel you need and seek confirmation from the refueller. If you forget to specify the fuel type, understand that when you are asked what type of fuel you want the refueller has your safety in mind. Stating your requirements and confirming them should be part of every order, regardless of how obvious the type of fuel required may seem or how frequently your aircraft is refuelled.
Aviation industry personnel are trained to be alert to the detail of their work and to the discipline of cross-checking. This safety culture is part of the industry and matched in few other workplaces.
The refuelling industry has several mechanisms to help prevent misfuellings, including colour coding of equipment and forms.
The use of wing decals provides an additional barrier against misfuelling by providing a powerful visual confirmation of fuel type immediately before fuelling. The wing decals are colour coded, as are the refuelling nozzles.
Pilots are strongly encouraged to fit and regularly replace wing decals, which are readily available from your local refuelling company. We have a policy of ‘no decal, no fuel.’ Wing decals must be fitted before refuelling.
Fuel-type decals are large and clearly visible colour-coded decals that are positioned on all fuelling storage, bowser and vehicle equipment. This also assists in fuel-type recognition.
Always check for the correct grade of fuel when your aircraft is refuelled.
Fuel-grade verification forms are used to gain written confirmation of the type of fuel required. They are used where the fuelling operator is uncertain about the correct grade to supply or where a selective spout cannot be used.
Selective nozzles utilise different-sized spouts for avgas and jet fuel. Jet fuel nozzles utilise a larger spout than avgas nozzles. The wide jet spout will not fit into the selective avgas fuelling port.
There are many avgas aircraft that aren’t, or can’t be, fitted with a selective fuelling port, so many will accommodate the wider nozzle. Additionally, some jet fuel aircraft – particularly helicopters – have fuelling ports too small to accept the wider spout, so a standard nozzle has to be fitted.
We strongly encourage pilots to fit the selective port modification kits which are available for most avgas-powered aircraft.
When you order a carnet card for your aircraft you will be asked whether you require an avgas or a jet fuel card.
Our card swipe bowsers are grade-specific: an avgas card will not operate a jet fuel bowser and vice versa.
Before filling, drums are colour-coded and clearly marked with the grade of fuel.
Misfuellings are fairly rare. The industry gets it right most of the time, but when it doesn’t, the outcomes may be tragic. A slight difference in routine, a last minute change in aircraft type, parking closer to the wrong fuel bowser can all cause misfuelling.
Most of the time it is because both refueller and pilot have made assumptions. At many locations, pilots and refuellers know each other well – the same aircraft is fuelled in the same location every day at the same time. It is important to correctly confirm the grade for every refuelling.
There are quite a few examples of similar looking aircraft that require different grades of fuel. The increasing numbers of aircraft undergoing engine conversions and the recent development of the diesel cycle aviation engine have added to the risk of misfuelling.
There are many documented cases of misfuelling and one common factor that is almost always present has been a failure to specify what type of fuel is required in the first instance.
Misfuellings are fairly rare. The industry gets it right most of the time, but when it doesn’t the outcomes may be tragic because of a slight difference in routine, a last minute change in aircraft type or parking closer to the wrong fuel bowser.
Most of the time it is because both the refueller and pilot have made assumptions. At many locations, pilots and refuellers know each other well – the same aircraft is fuelled in the same location every day at the same time. It is important to correctly confirm the grade for every refuelling.