Figure 6-6-7. Cargo Door and Ramp

Figure 6-6-6. External Cargo Moments Chart (Sheet 2 of 2)

TM-1-1520-240-10 Army CH-47D Heilcopter (EIC:RCD) Manual
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TM 1-1520-240-10 6-6-14 6-6-21. Winch. Refer to Chapter 4, Section III. 6-6-22. Cargo Door and Ramp. The cargo door and ramp has an upper section, or cargo door, and lower section, or ramp. The door retracts into the ramp when the ramp is being lowered and extends when the ramp is being raised. Retraction or extension of the door can be isolated through the ramp sequence valve so the ramp can be raised or lowered with the door retracted into the ramp or extended. The door is an inte- gral part of the ramp and only provides closure; therefore, references made to the ramp will be understood to in- clude the door and its related movements. The cargo door is jettisonable to provide an emergency exit. The cargo door and ramp is located at the aft end of the cargo compartment and is used for troop and cargo loading and unloading. In closed position, it conforms to the side con- tours of the fuselage (fig. 6-6-7). Internal locks in the ramp actuating cylinders prevent accidental opening and constitute the only locking mechanism for keeping the ramp closed. The ramp is hinged to the fuselage and opens rearward and downward to rest on the ground. When lowered to ground rest, the ramp inclines down- ward approximately 6.75_ and maintains a uniform 78-inch overhead clearance, (if HICHS is not installed), of the cargo compartment. A continuous hinge runs the entire width of the aft upper edge of the ramp and holds the three auxiliary loading ramps. The auxiliary ramps unfold to bridge the gap between the ramp and the ground for vehicle loading and unloading. they can be adjusted laterally to accommodate various vehicle thread widths. Hydraulic power to operate the ramp is supplied through the utility hydraulic system. 6-6-23. RAMP CONTROL Valve. Lowering and raising the ramp is controlled by a RAMP CONTROL valve on the right side of the aft cargo compartment between the floor and the overhead at sta 490 (fig. 6-6-8). The RAMP CONTROL valve is operated either electrically or manually. Electrical operation is per- formed by setting the RAMP PWR switch to EMERG, and using the RAMP EMER control switch on the cockpit overhead HYD control panel (Chapter 2, Section VI). Manual operation is accomplished by setting the RAMP PWR switch to ON, and using a three-position lever mounted on the RAMP CONTROL valve. the lever posi- tions are labeled UP, STOP, and DN (down). The control lever can be reached from the outside through a hinged panel on the aft fuselage. Figure 6-6-7. Cargo Door and Ramp

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