Misfuelling

What is misfuelling?

Misfuelling, or filling an aircraft with the incorrect fuel type, is a risk that exists because GA aircraft are generally fuelled via the overwing method using a hand held trigger nozzle.

There are a number of aircraft that require different types of fuel, such as Jet or Avgas, but that are quite similar looking aircraft. In addition, some recent changes to aircraft engines (including the introduction of compression ignition piston engines that run on Jet fuel) have added to the risk.

The consequences of misfuelling can be devastating, especially when Jet fuel is delivered into piston-powered aircraft that actually requires Avgas. If the two different types of fuel blend within an aircraft’s tank, the engine performance can be severely affected, leading to total engine failure. This happens because Jet fuel (kerosene) does not burn particularly well in an internal combustion engine. It is like putting diesel into your petrol-operated car.

There are many documented cases of misfuellings 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.

Preventing misfuelling

The refuelling industry has several mechanisms to help prevent misfuellings, including colour coding of equipment and forms.

Wing decals

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 (grade) decals

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

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

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.

Fuel-grade carnet cards

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.

Ordering your fuel

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.