CAUTION REFUELING AIRCRAFT WITH AUXILIARY POWER UNIT (APU) RUNNING The aircraft APU maybe used to supply electrical power for pressure refueling on military aircraft so equipped. Refueling with the APU running is not conducted in the hangar deck. Although this operation is not considered “hot refueling,” the following pre- cautions must be observed, in addition to the normal refueling procedures: 1. One person will be at the APU controls in the cockpit. 2. Hand signals/signal wands must be established between cockpit and personnel performing refueling to ensure immediate shutdown in an emergency. DEFUELING AIRCRAFT Defueling is one of the most technically demand- ing and potentially dangerous operations performed by fuels personnel. Most aircraft defueling equipment can defuel an aircraft faster than the aircraft cart re- lease it. The pump’s discharge is throttled down to balance its inlet (fuel from the aircraft) to prevent pump cavitation and/or the loss of suction, which would necessitate reflooding of the pump. Once the proper balance is achieved, it is maintained by ma- nipulation of the valve on the downstream side of the pump throughout the defueling operation. Defuelings normally have lower priority than re- fueling. Unless otherwise directed and if they are not of an emergency nature, defuelings will be by written request approved by the Aircraft Handling Officer (ACHO). A defuel request for an aircraft leaking fuel is considered an emergency and handled promptly. The following rules apply to every defueling op- eration: Aircraft defueling must be requested by an authorized representative of the squadron by complet- ing and submitting an Aircraft Defueling Certificate to the ACHO. During defueling operations, no other mainte- nance not directly required to aid the defueling opera- tion is to be performed. Fuel with a flash point below 140°F SHALL NOT be defueled into the ship’s JP-5 system. These systems are not designed to han- dle fuel with a lower flash point. The risk of explosion and/or fire will significantly increase if fuel with a low flash point is placed in these systems. All fuel removed from turbine engine aircraft is assumed to be low-flash-point fuel. Defueled jet fuel will NOT be returned to the ship’s JP-5 system without first confirming the flash point of the fuel to be 140°F or higher. Prior to any defuel, fuel will be tested for particu- lates, free water, and flash point. Ultimate disposition will depend on the results of subsequent laboratory tests. Additionally, JP-5 containing leak-detection dye cannot be returned to a ship’s system. If during the defuel operation the pump starts to lose prime or cavitate, the operation will be discontin- ued until the problem is resolved. A special log of each defueling operation will be maintained. The following minimum information is contained in the log: — — — — All abnormal happenings. Aircraft Buno number. Station/portable defuel. Visual/flashpoint. Scheduled amount to be removed and amount that was actually removed. Disposition of product. Time/date when the defuel operation was started and completed. – Name of defuel operator and squadron personnel present during the defuel operation. Defueling crews must wear proper safety cloth- ing and goggles. Plane captains will be at their aircraft, and air- craft engines stopped. All electronic and electrical switches not required for defueling must be secured. 5-21