Fuel
Different engines require different types of fuel to function properly. As a rule, piston engines must use the type AVGAS as fuel. This type of fuel works like regular gasoline. AVGAS can have different octane contents and lead additives. The two most common types of AVGAS are 100LL and 91/96. The type to be used is stated in the ** flight manual ** (POH - Pilot Operating Handbook). LL stands for low lead while the other variety is lead free.
Recently, some diesel engines have also been developed for light aircraft. These must be refuelled with ordinary diesel which has the same properties as the diesel used for certain cars and trucks. Diesel is also similar to jet fuel of the type JET A1 which is used for heavier machines with jet engines or turboprop engines. The JET A1 can also be refuelled in most diesel engines.
It is important to refuel an aircraft with the intended fuel as the engine may otherwise cut with an engine failure as a result!
Regulations
When flying VFR, there are rules that determine how we are to calculate the fuel consumption and how much reserve fuel to carried onboard during flight. This is published in LFS 2007:71 - "Luftfartsstyrelsens föreskrifter och allmänna råd om privatflygning med ultralätta flygplan" in Series OPS. These rules include:
"the aircraft's fuel and oil reserves are sufficient for the intended flight, taking into account winds on the route and other meteorological conditions.
the fuel calculation is based on the manufacturer's information or is based on measured and verified consumption for the aircraft individual and intended flight conditions.
there is a fuel reserve for 30 minutes flight."
Planning
Before all flights, a fuel plan must be prepared. Fuel calculations shall be based on** manufacturer's information** for flights with rich mixture or based on measured and verified consumption for the aircraft individual and the intended flight conditions in question. Fuel quantity must be stated as volume and time.
A fuel plan for each flight shall contain at least the following information:
- Fuel to destination
- Fuel for expected delays
- Prescribed reserve fuel
- Contingency fuel
For a distance flight, a flight that extends more than 25NM from the departure airport, an operational flight plan must also be prepared. This operating flight plan must be carried onboard and followed up to show, among other things, that there is sufficient fuel onboard to the destination and at least a final reserve of 30 minutes.
When calculating take-off mass, you use the unit kilogram in Europe. However, you refuel in litres. It is therefore important to be able to convert the volume of the fuel to weight in order to obtain the exact take-off mass. If no other value is specified, a standard value must be used for these calculations in accordance with the regulations. AVGAS (piston engine fuel) weighs according to the regulations 0.71 kilos per litre. JET A1 (both diesel and jet fuel) weighs according to the regulations 0.82 kilos per litre.
Reserves
When flying according to VFR with a piston engine, the fuel reserve that is carried must be prepared for continued flight for at least 30 minutes.
When flying according to VFR, emergency must be declared if an airport where a safe landing can be made cannot be reached on the remaining amount of fuel!
Refuelling
The refuelling area is the area of which flammable gases may occur in connection with refuelling of an aircraft. At airports, there are regulations on where there is a smoking ban. If there is no such marked area, smoking is prohibited closer than 20 metres from aircraft, tank facilities, fuel trucks or hangars.
When refuelling, the aircraft must be connected to earth to prevent sparking. This must always be done! Either at a refuelling facility or at a refuelling truck. In addition, there must be a fire extinguisher on hand during the entire refuelling. If a fuel truck is used, the parking brake must be applied on the truck and it must be parked in such a way that it can easily be driven away if needed.
Refueling may not be carried out if the aircraft's brakes are abnormally heated or if the weather radar system in the aircraft is on. In addition, engines may not normally be running, however, exceptions to this may be granted by the Swedish Transport Agency. During thunderstorms or if there is a risk of lightning strikes within the area refuelling should be avoided.