Section IV. FUEL SYSTEM

TM 1-1520-238-10 2-34 Change 2 Section IV. FUEL SYSTEM 2.36 FUEL SYSTEM. The fuel system provides fuel and fuel management provi- sions (fig 2-22) to operate both engines and the APU. Fuel is stored in two crash-resistant, self-sealing fuel cells: one forward and one aft of the ammunition bay (fig 2-23). Fuel may be transferred from either cell to the other. The sys- tem is also equipped to crossfeed (select which fuel cell supplies fuel to the engines). The helicopter has provi- sions for carrying either two or four external fuel tanks on the wing pylon attach points. Approved primary fuel grades and acceptable alternates are listed in Section XV, table 2-8. M01-015 PILOT Figure 2-22. Pilot Fuel Control Panel M01-325 PILOT SWITCH BARRIER Figure 2-22.1 Pilot Fuel Control Panel (Modified) 2.36.1 Pilot Fuel Control Panel. Table 2-1 outlines the effects of switch settings on the pilot fuel control panel (fig 2-22). Some fuel control panels have been modified with switch barriers located on the ENG 1 and ENG 2 fuel switches (fig 2-22.1). The following paragraphs contain a description of fuel system provisions controlled by the panel. a. Fuel Switch. Two switches, ENG 1 and ENG 2, control the activation of the crossfeed shutoff valves. In or- der for fuel to flow to the engines (or crossfeed to the op- posite engine if selected), the respective fuel switch must be ON. When in the ON position, the crossfeed switch is enabled. This controls the positioning of the crossfeed valve. WARNING � The crossfeed switch shall be set to the NORM position at all times, in flight, unless executing emergency procedures for FUEL PSI ENG 1 and FUEL PSI ENG 2 warning advisory. A malfunctioning crossfeed valve could result in a single engine flameout. � Do not switch directly from AFT TK to FWD TK crossfeed (or FWD TK to AFT TK) without pausing for at least 15 seconds in the NORM position to en- sure both valves are sequencing to their proper positions. Failure to fol- low this procedure may result in a dual engine flameout if one of the cross- feed valves fails to properly position. b. Crossfeed Switch. This switch simultaneously controls the position of both crossfeed/shutoff valves. Three discrete positions, FWD TK, NORM and AFT TK al- low the pilot to select the fuel cell(s) to feed both engines. The NORM setting feeds the No. 1 engine from the for- ward cell and the No. 2 engine from the aft cell. Both en- gines will feed from either the FWD TK or AFT TK when selected. This allows the pilot an emergency means to continue flight to a safe area after sustaining fuel system damage. The crossfeed switch can still be used on the ground to control fuel feed during hot refueling. CROSS- FEED switch must be placed in the NORM position at least 30 seconds prior to takeoff. If the ENG 1 or ENG 2 fire pull handle is pulled, the