FUELLING GENERAL AVIATION AIRCRAFT: AVGAS OR JET FUEL

While the majority of aircraft fuelled overwing are piston-engined, requiring aviation gasoline, the growth of turbine aircraft requiring jet fuel overwing is significant. Fuel supply systems need increasingly to be equipped with nozzles so that either grade may be offered overwing. Aircraft particularly vulnerable to incorrect grade delivery are piston engined types with sister aircraft from the same manufacturer fitted with turbo-props. At first glance they are identical and certainly there is no difference in the size and arrangement of the fuel fill points. Yet it is well known that even a few percent of jet fuel mixed with Avgas can be disastrous, particularly during take-off. To add further to the confusion, some of the piston engines are supercharged and have the word TURBO on the engine cowling. Language differences provide another snare. For example, kerosene in French is petrole, which may be confused with petrol, the commonly used English name for gasoline. The ideal solution would be to introduce a grade selective system by ensuring, for example, that overwing nozzles used for delivering jet fuel are too big to enter the fuel orifice of a piston engined aircraft. Meanwhile, it is proposed that the pilot be required to sign an order form exactly specifying the fuel required.