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