The first step in fueling is “grounding” the airplane to allow any static electricity that may lurk in the airframe to find a safe path to the ground, and not discharge as a spark that could ignite the fuel vapor.
At most self-serve fueling stations, the grounding cable is found near the pump in a reel that commonly features a geared, spring-loaded mechanism designed so that the cable is easy to pull out, will lock into place while in use, and then easily retracts—removing a trip hazard—when the fueling is completed.
This procedure assumes that the reel is in good shape, which is not always the case. Sometimes, no matter how hard you try, the reel simply will not lock into place and is eager to snatch the cable back away from you. In such cases, pull more cable than you need, and wrap it once or twice around the base of your airplane’s nosewheel to keep it from escaping. You’ll have plenty, as the common grounding cable lengths at general aviation fuel pumps are 50 and 75 feet. Airports serving larger airplanes have cables up to 125 feet long.
To rewind the cable after fueling, pull the cable toward you to release the clutch in the reel, and the reel will start to rewind the cable.
The courteous methodology is to then “walk” the grounding clip assembly back to the reel, sort of like taking an eager dog for a walk. The impolite way is to simply drop the cable on the ground and let it bounce and slither across the tarmac like a scared snake. This is bad for the equipment and could hurt an innocent co-pilot or passenger who might be standing nearby.
Now, sometimes the opposite of the “won’t lock” failure happens, and the cable won’t rewind for love or money. In this case, just walk the cable back and make a large, neat coil of it on the ground in front of the reel. Don’t wind the cable around the base of the reel, as this just makes more work for the next pilot who needs to use it.
Also, remember to replace the fuel cap after the fuel tank is filled!