Chapter 11. Safety, Ground Operations, & Servicing Fueling Hazards The volatility of aviation fuels creates a fire hazard that has plagued aviators and aviation engine designers since the beginning of powered flight. Volatility is the ability of a liquid to change into a gas at a relatively low temperature. In its liquid state, aviation fuel will not burn. It is, therefore, the vapors, or gaseous state to which the liquid fuel changes that is not only useful in powering the aircraft, but also a fire hazard. Static electricity is a byproduct of one substance rubbing against another. Fuel flowing through a fuel line causes a certain amount of static electricity. The greatest static electricity concern around aircraft is that during flight, the aircraft moving through the air causes static electricity to build in the airframe. If that static electricity is not dissipated prior to refueling, the static electricity in the airframe will try to return to ground through the fuel line from the servicing unit. The spark caused by the static electricity can ignite any vaporized fuel. Breathing the vapors from fuel can be harmful and should be limited. Any fuel spilled on the clothing or skin must be removed as soon as possible. Fueling Procedures The proper fueling of an aircraft is the responsibility of the owner/operator. This does not, however, relieve the person doing the fueling of the responsibility to use the correct type of fuel and safe fueling procedures. There are two basic procedures when fueling an aircraft. Smaller aircraft are fueled by the over-the-wing method. This method uses the fuel hose to fill through fueling ports on the top of the wing. The method used for larger aircraft is the single point fueling system. This type of fueling system uses receptacles in the bottom leading edge of the wing, which is used to fill all the tanks from this one point. This decreases the time it takes to refuel the aircraft, limits contamination, and reduces the chance of static electricity igniting the fuel. Most pressure fueling systems consist of a pressure fueling hose and a panel of controls and gauges that permit one person to fuel or defuel any or all fuel tanks of an aircraft. Each tank can be filled to a predetermined level. These procedures are illustrated in Figures 11-31 and 11-32. Prior to fueling, the person fueling should check the following: Ensure all aircraft electrical systems and electronic devices, including radar, are turned off. Do not carry anything in the shirt pockets. These items could fall into the fuel tanks. Ensure no flame-producing devices are carried by anyone engaged in the fueling operation. A moment of carelessness could cause an accident. Ensure that the proper type and grade of fuel is used. Do not mix AVGAS and JET fuel. Ensure that all the sumps have been drained. Wear eye protection. Although generally not as critical as eye protection, other forms of protection, such as rubber gloves and aprons, can protect the skin from the effects of spilled or splashed fuel. Do not fuel aircraft if there is danger of other aircraft in the vicinity blowing dirt in the direction of the aircraft being fueled. Blown dirt, dust, or other contaminants can enter an open fuel tank, contaminating the entire contents of the tank. Do not fuel an aircraft when there is lightning within 5 miles. Do not fuel an aircraft within 500 feet of operating ground radar. When using mobile fueling equipment: Approach the aircraft with caution, positioning the fuel truck so that if it is necessary to depart quickly, no backing will be needed. Set the hand brake of the fuel truck, and chock the wheels to prevent rolling. Ground the aircraft and then ground the truck. Next, ground or bond them together by running a connecting wire between the aircraft and the fuel truck. This may be done by three separate ground wires or by a “Y" cable from the fuel truck. Ensure that the grounds are in contact with bare metal or are in the proper grounding points on the aircraft. Do not use the engine exhaust or propeller as grounding points. Damage to the propeller can result, and there is no way of quickly ensuring a positive bond between the engine and the airframe. Ground the nozzle to the aircraft, then open the fuel tank. Protect the wing and any other item on the aircraft from damage caused by spilled fuel or careless handling of the nozzle, hose, or grounding wires. Check the fuel cap for proper installation and security before leaving the aircraft. Remove the grounding wires in the reverse order. If the aircraft is not going to be flown or moved soon, the aircraft ground wire can be left attached. When fueling from pits or cabinets, follow the same procedures as when using a truck. Pits or cabinets are usually designed with permanent grounding, eliminating the need to ground the equipment. However, the aircraft still must be grounded, and then the equipment must be grounded to the aircraft as it was with mobile equipment.

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