CONTINUITY

is to insert the defueling suction hose into the tank through the tank fill opening. For total defueling, defuel through the aircraft pressure fueling adapter. The discharge hose from the defueling unit is connected to the fill connection through a special fitting. CONTINUITY Electrical continuity is a firm requirement for all aircraft refueling stations. Electrical continuity must be present and maintained to ensure personnel safety, equipment protection, and efficient fueling operations. With electrical continuity present, the nozzleman fueling the aircraft has immediate control of fuel flow. This is essential to prevent fuel spills and possible accidents during aircraft refueling. Electrical continuity is present when wires are provided and switches are set to allow an electrical current to flow away from the controller and back to it through a solid metallic path. Now, let’s follow the continuity circuit (fig. 5-17). Starting the defuel pump applies power to the solid state relay, but nothing happens, because the circuit is broken. Make sure your ground wire to the deck is grounded to metal. Then hook it to the aircraft. Remove the dust cover and connect the nozzle. Flip the switch in the quick-disconnect housing to ON, which closes the circuit. The ground then goes back through the spiders in the quick-disconnect coupling to the wire in the hose. From there, it goes back to the Figure 5-17.—Electrical continuity control for the Cla-Val fueling station. 5-16