AVIATION FUELS ARE CLASSIFIED INTO TWO GROUPS
- Avgas 100LL (aviation gasoline): available at Wilson Airport only.
- Jet A-1 (aviation turbine fuel): available at all our airport locations in Kenya.
Manufacturing specifications for aviation fuels are very stringent. When necessary, at every stage between refinery and aircraft tank, fuel quality is checked by sampling and laboratory analysis to ensure that the fuel conforms to the specification when it is delivered to the aircraft.
Avgas 100LL is a gasoline fuel for use in reciprocating piston engined aircraft. As with all gasoline, Avgas is very volatile and is extremely flammable at normal operating temperatures. Procedures and equipment for safe handling of this product must therefore be of the highest order.
Avgas 100LL aviation fuel has an octane rating of 100 and the LL stands for ‘low lead’. The octane rating ensures satisfactory combustion qualities defined as the anti-knock rating. The other properties are the distillation range and volatility which are important for mixture distribution and cold starting. Other specification items are included to ensure that the fuel has good storage life, will not corrode engines or fuel system components and can be satisfactorily supplied to the engine under all operating conditions.
All equipment and facilities handling Avgas 100LL are colour-coded and display prominently the API markings denoting the actual grade carried. To ease identification the fuels are dyed and Avgas 100LL is coloured blue.
Avgas fuelling nozzles for over wing dispensing are painted red, to help prevent the possibility of jet fuel being supplied to a piston engined aircraft. Nozzles for jet fuel (painted black) are normally a different shape and larger diameter than the aperture on most aircraft Avgas tanks.
Aviation turbine fuels are used for powering jet engines, turbo-prop engines and more recently diesel piston engines in aircraft.
Jet A-1 is a kerosene grade of fuel suitable for most turbine engine aircraft. It is produced to a stringent internationally agreed standard, has a flash point above 38ºC (100ºF) and a freeze point maximum of -47ºC. Jet A-1 is the usual fuel for turbines in the world. Jet A-1 meets the latest version requirements of British specification DEF STAN 91-91, ASTM specification D1655 and NATO Code F-35.
In specifying requirements for jet fuels, the main objective is to ensure that fuel systems will function satisfactorily over a wide range of temperatures and pressures.
These environmental factors can be very severe owing to the conditions under which modern jet aircraft operate. In addition to these requirements, engine developments and the continual effort to lengthen the period between engine overhauls has led to the introduction of a number of new sophisticated specification requirements, far removed from those for aviation gasoline. Among these are the need for high thermal stability, low luminosity and compatibility with certain fuel system materials.
Aviation kerosene is the most common fuel in commercial use. The standard civil grade of aviation turbine fuel, Jet A-1, is manufactured to meet the requirements of the latest version of the Aviation Fuel Quality Requirements for Jointly Operated Systems (AFQRJOS) "Check List".
The Check List was drawn up by the major international oil supply companies to ensure uniform quality standards for civil jet fuels world-wide (excluding USA) and comprises the most restrictive requirements of the major fuel specifications. Compliance with Check List requirements thus guarantees meeting the requirements of the individual specifications.