TM 55-1520-240-23-10 16-59.1 AN/ALE-47 COUNTERMEASURES DISPENSER SYSTEM DESCRIPTION AND THEORY OF OPERATION 16-59.1 DESCRIPTION The AN/ALE-47 Countermeasures Dispenser System (CMDS) is comprised of the following components:  a Digital Control Display Unit (DCDU), a programmer, a junction box, two sequencers, and four dispenser assemblies each containing a payload module (magazine).  The system also contains a safety switch, a Mission Load Verifier (MLV) interface port, flare dispense buttons on the pilot’s and copilot’s cyclic grip, four crew dispense buttons, and a landing gear bypass switch status panel. The DCDU (located in the center console), provides cockpit interface for manual inputs, such as mode selection, payload inputs, manual dispense program selection, emergency jettison of expendables, and other operational commands.  It also displays system status built-in test, expendable inventories, selected functions, and other system feedback data. The AN/ALE-47 programmer, located at STA 355.00 in the left side of the cabin, is the central processing unit for the CMDS and provides the interface between the DCDU and the four flare dispensers via two sequencers.  The programmer receives input data from the AN/ALQ-156 missile detection system, processes it to determine the appropriate dispense response, and sends fire commands to the sequencers when the CMDS is in Auto or Semi Auto mode of operation. The software program within the programmer that manages all communications,  operations,  and calculations is called the Operational Flight Program (OFP). The programmer also contains the Mission Data File (MDF) which is user-programmable and contains data elements that enable the CMDS to be configured to specific payload types, dispense sequence, and dispense quantities. The OFP and MDF are loaded into the programmer using the Mission Load Verifier (MLV) via the MLV interface port located in the cabin at STA 359.00 overhead. The junction box provides a centralized location for easy access to CMDS electrical connections between system components while reducing electro magnetic interference impact in the cabin. There are two AN/ALE-47 sequencers installed in the aft cabin at STA 547.00 BL40R and STA 543.00 BL40R. The sequencers receive payload type and fire commands from the programmer over the Sequencer Data Link (SDL). The sequencers select the dispenser with the appropriate payload and send high power impulses to the dispenser and magazine to dispense the programmed expendable.  The sequencers also detect magazine type, monitor the remaining inventories in the magazines, and detect payload misfires.  This information is sent to the programmer via the SDL. Each sequencer also performs internal BIT. Sequencer No.  1 controls the two dispensers (1 and 3) on the LH side of the aircraft, and sequencer No.  2 controls the two dispensers (2 and 4) on the RH side of the aircraft. A safety switch located at STA 518.00 BL50L is installed in the CMDS to provide a safeguard against inadvertent dispensing of the expendables.  When the safety pin is installed in the safety switch, squib power (28 vdc) from the programmer to the sequencers is interrupted, inhibiting dispensing of expendables.  The safety switch provides ground to the AN/ALE-47 squib power relay (located in the AN/ALE-47 junction box at STA 410.00 BL22.5L) when safety pin is removed allowing squib power to the sequencers. Four flare dispenser assemblies are mounted in pairs on the LH and RH sides of the aft fuselage. Each dispenser assembly consists of housing and a breech. The breech provides interface for the payload module and routes firing and polling pulses from the sequencers to the payload squibs. The payload module assemblies are mounted on the dispenser assemblies.  Each payload module assembly consists of a payload module and breech plate.  The payload modules can hold up to 30 expendable cartridges which are loaded and installed in the dispenser assemblies prior to the mission. Manual dispensing of expendables is done by pressing the FLARE DISP buttons on the pilot’s and copilot’s cyclic grip or by using one of the four crew dispense buttons located at STA 200.00 and 400.00 L and R in the cabin. Setting the DCDU MODE switch to MAN and the MANUAL switch to positions 1, 2, 3, or 4, enables the pilot or copilot to manually dispense expendables. Manual dispensing by crewmembers is accomplished by pressing one of the four crew dispense buttons with the DCDU mode switch in MAN. The landing gear bypass switch status panel enables testing of the CMDS when the aircraft is in a weight-on-wheels (WOW) condition by allowing the proximity switch on the aft landing gear to be bypassed. During normal operations, the NORMAL/BYPASS switch on landing gear bypass switch status panel is in the NORMAL position.  During testing and maintenance, the switch is placed in the BYPASS position, which bypasses the proximity switch to enable the CMDS. 16-250.2 Change 1