maintenance/operations manual should be consulted before  proceeding. Note that an over-the-wing refueling nozzle  for turbine engine fuel should be too large to fit into the fill  opening on an aircraft utilizing gasoline.  Clean the area adjacent to the fill port when refueling over  the wing. Ensure the fuel nozzle is also clean. Aviation fuel  nozzles are equipped with static bonding wires that must  be attached to the aircraft before the fuel cap is opened.  [Figure 14-104]  Open the cap only when ready to dispense  the fuel. Insert the nozzle into the opening with care. The  aircraft structure is much more delicate than the fuel nozzle,  which could easily damage the aircraft. Do not insert the neck  of the nozzle deeply enough to hit bottom. This could dent  the tank, or the aircraft skin, if it is an integral tank. Exercise  caution to avoid damage to the surface of the airframe by the  heavy fuel hose. Lay the hose over your shoulder or use a  refueling mat to protect the paint.  [Figure 14-105] When pressure refueling, the aircraft receptacle is part of a  fueling valve assembly. When the fueling nozzle is properly  connected and locked, a plunger unlocks the aircraft valve  so fuel can be pumped through it. Normally, all tanks can be  fueled from a single point. Valves in the aircraft fuel system  are controlled at the fueling station to direct the fuel into  the proper tank.  [Figure 14-106]  Ensure that the pressure  developed by the refueling pump is correct for the aircraft  before pumping fuel. Note that, while similar, pressure  fueling panels and their operation are different on different  aircraft. Refueling personnel should be guided through the  correct use of each panel. Do not guess at how the panel and  associated valves operate.  When fueling from a fuel truck, precautions should be taken.  If the truck is not in continuous service, all sumps should  be drained before moving the truck, and the fuel should be  visually inspected to be sure it is bright and clean. Turbine  There are other miscellaneous good practices that should  be employed when refueling an aircraft. A ladder should be  used if the refuel point is not accessible while standing on  the ground. Climbing on an expensive aircraft to access the  fueling ports is possible but does not give the stability of a  ladder and may not be appreciated by the aircraft owner. If it  is necessary to walk on the wings of the aircraft, do so only  in designated areas, which are safe.  The aircraft should be approached slowly. The truck should  be parked parallel to the wings and in front of the fuselage if  possible. Avoid backing toward the aircraft. Set the parking  brake and chock the wheels. Connect a static bonding cable  from the truck to the aircraft. This cable is typically stored  on a reel mounted on the truck. fuel should be allowed to settle for a few hours if the fuel truck  tank has recently been filled or the truck has been jostled,  such as when driven over a bumpy service road at the airport.  Properly maneuver the fuel truck into position for refueling. 14-57 Figure 14-105.  Over-the-wing refueling a Cessna. Figure 14-106.  This panel at the pressure refueling station has valve  position switches and quantity gauges to be used during refueling. Valve open position lights are adjacent to the switches for each tank.  Figure 14-104.  An AVGAS fueling nozzle with static bonding  grounding wire.