Normal engine operation depends on the use of proper fuel grade

1. PTE DATE :
FUEL
SYSTEM
NAME :
AVIATION FUEL GRADES
Normal engine operation depends on the use of proper fuel grade. If the proper grade of fuel is not available, it is
sometimes permissible to use the next higher grade of fuel
for example ; 100 LL rather than 80
never allow a grade lower than that specified for normal operation to be used. To do so may cause extensive damage
to the engine. Aviation fuels are color coded to help prevent the fueling of aircraft with the wrong fuel. Fuels are
colored as follows :
Octane Color
80 Red
100 LL Blue
100 Green
115 (Military use only) Purple
JET A Clear or straw colored
in recent years, the availability of 80-octane (red) fuel has diminished. Instead, fuel suppliers have been providing 100
LL (100 octane, LOW LEAD) for use in all light, piston engine airplanes. Some engines designed for 80-octane fuel
require modifications for the continuous use of 100 LL. Additionally, maintenance problems in some engines,
primarily exhaust valve erosion and spark plug fouling, have been attributed to the higher lead fuel (despite its name,
100 LL contains four times the lead of 80 octane). Engine manufacturers advise strict adherence to their latest
recommended operating procedures to help assure the proper operation of the affected engines.