SECTION I. EQUIPMENT DESCRIPTION AND DATA

TM 1-1520-238-T-7 10–2 SECTION I. EQUIPMENT DESCRIPTION AND DATA 10–1. EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES 10–1 a. Characteristics. (1) Fuel Storage System. The purpose of the fuel storage system is to store fuel for distribution to the engines and the auxiliary power unit (APU). (2) Fuel Crossfeed/Boost System. The fuel crossfeed/boost system provides fuel to the forward and aft fuel cells for starting and normal helicopter operation. (3) Fuel Quantity Indication/Transfer System. The fuel quantity indication/transfer system allows crew members to monitor fuel quantity and to transfer fuel from cell to cell to maintain helicopter center of gravity, or to transfer fuel from a damaged cell. (4) Nitrogen Inerting System. The nitrogen inerting system reduces fire hazards associated with fuel cell air space by filling air space with oxygen-depleted air to a level that does not support combustion. (5) Gravity Refueling/Defueling. Gravity refueling/defueling provides a means for refueling or defueling the forward and aft fuel cells. (6) Pressure Refueling/Defueling. The pressure refueling/defueling system allows pressure refueling or suction defueling of the forward and aft fuel cells. (7) Auxiliary Fuel System. The auxiliary fuel system transfers fuel from the auxiliary fuel tanks to the internal fuel cells. Auxiliary fuel tanks store and supply fuel for ferry operations. b. Capabilities and Features. (1) Fuel Storage System. The fuel storage system provides fuel and fuel management provisions to operate both engines and the APU. Fuel is stored in two crash-resistant, self-sealing fuel cells, one forward and one aft. Fuel may be transferred from one fuel cell to another. The fuel system also enables either crewmember to select fuel supply to engines. (2) Fuel Crossfeed/Boost System. The fuel crossfeed/boost system provides fuel pressure to the engine-driven fuel pumps during engine start-up. Positive fuel pressure is provided at altitudes over 10,000 feet. A crossfeed/shutoff valve allows or disables either cell to supply or shutoff fuel to both engines. (3) Fuel Quantity Indication/Transfer System. The fuel quantity indication/transfer system uses the pressurized air system (PAS) to direct air for fuel transfer. FUEL panels provide crew members quick access for fuel management. Fuel quantity is continuously monitored and various panels indicate fuel level. (4) Nitrogen Inerting System. The nitrogen inerting system provides a continuous oxygen-depleted airflow to both fuel cells, approximately 94% nitrogen. It is self-contained and automatically operates whenever pressurized air and 115 VAC power is available. (5) Gravity Refueling/Defueling. The gravity refueling/defueling system fuels the forward, and aft fuel cells, and the auxiliary tanks separately. Refueling time required for gravity refueling is dependent upon the flow-rate capability of the servicing equipment. (6) Pressure Refueling/Defueling. The pressure refueling/defueling system provides two adapters for alternative fuel nozzles. Forward and aft fuel cells may be filled separately or simultaneously dependent upon refueling panel switch settings. Fuel quantity is continuously monitored and fuel flow is automatically stopped by fuel cell sensors.