BONDING OR GROUNDING DURING REFUELLING AN AIRCRAFT

BONDING OR GROUNDING DURING REFUELLING AN AIRCRAFT

Grounding the aircraft and fuelling vehicle had been believed to be the safest way to dissipate the electrostatic charges caused by the refuelling process of an aircraft until the National Fire Protection Association (NFPA) published a Bulletin in which it was stated that bonding was safer than grounding.

Electrostatic charge caused by filtration and pumping of fuel is basically the separation of the pluses from the minuses. As the fuel passes from the refuelling vehicle to the aircraft the minuses or pluses go along with the fuel to the aircraft and the other stays behind in the filter generating a large voltage difference. That is why a conducter (bonding cable) is needed to equalize the potential charge between the refueller and aircraft.

Grounding the aircraft and grounding the fuelling vehicle was a good way to ged rid of the electrostatic energy caused during refuelling. But later on it was observed and experienced that grounding cables were insufficient and carried no charge at all from apparatus such as ground power units, generators or charges from fuelling vehicles.

Bonding the refuelling vehicle and aircraft is the best way to equalize the charge between them. To put it another way it is better to sent the pluses or minuses back where they come from.

In conclusion as grounding cables are insufficent to dissipate the electrostatic charge, bonding the aircraft to the source of fuel such as refuelling trucks or hydrant servicers is the best way.