CARGO RAMP AND DOOR EMERGENCY CONTROL SYSTEM OPERATIONAL CHECK (Continued)

CARGO RAMP AND DOOR EMERGENCY CONTROL SYSTEM OPERATIONAL CHECK

RAMP DOES NOT MOVE DOWN (RAMP IN CLOSED POSITION)

TM-55-1520-240-T-1 CH-47D Heilcopter Manual
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TM 55-1520-240-T 7-3.4.1 CARGO RAMP AND DOOR EMERGENCY CONTROL SYSTEM OPERATIONAL CHECK (Continued) 7-3.4.1 TASK RESULT 1. Apply electrical and hydraulic power. 2. Perform cargo ramp and door manual operational check making sure cargo ramp and door are completely closed when finished. 3. Check that RAMP EMER CONT circuit breaker (1) is closed and RAMP PWR switch is set to OFF. 4. With RAMP PWR switch (2) set to ON, lift guard of RAMP EMER switch (3) and set switch to DN and UP. 5. Set RAMP PWR switch (2) to EMERG. Check movement of ramp control valve handle (5). 6. Lift guard of RAMP EMER switch (3) and momentarily move switch to DN. 7. Lift guard of RAMP EMER switch (3) and momentarily move switch to DN and then UP positions before releasing switch to the HOLD position. 8. Lift guard of RAMP EMER switch (3) and hold switch in DN position until ramp fully opens. Move switch to UP and release switch when ramp is at a level position. Proper ramp and door operation as described in task 7-3.4, must be achieved prior to performing the following checks and procedures. If RAMP EMER CONT circuit breaker (1) is open, close it. If it opens again, go to task 7-3.13. Ramp shall not move and condition of ramp control valve shall not change. If handle to ramp control valve stiffens or operates, check wiring between RAMP PWR and RAMP EMER switches. If switches are wired in accordance with wiring diagram with [65], replace RAMP PWR switch. Mechanism of handle (5) shall stiffen and resist movement. Handle shall return to STOP (center) position if moved to either UP or DN position. If ramp control valve does not operate as described, go to task 7-3.14. Spring in RAMP EMER switch (3) shall return switch to HOLD position when switch is released. Ramp control valve handle (5) shall move to DN position and ramp system shall open for approximately five seconds in proper sequence (cargo door retracts and ramp moves downward). After approximately five seconds, ramp control valve handle (5) shall return to STOP; and, ramp shall stop opening and hold its position. If RAMP EMER switch, ramp system, or control valve fail to operate properly, go to task 7-3.15. Ramp control valve handle (5) shall move to DN, UP and back to STOP positions. Ramp shall open then stop before five seconds is complete. If ramp system fails to operate properly go to task 7-3.15. Ramp control valve handle (5) shall move to DN position and ramp shall fall to the end of its travel. When RAMP EMER (3) switch is released, ramp control valve handle shall return to STOP or center position. When RAMP EMER switch is moved and held in UP position, ramp control valve handle shall move to its UP position and ramp shall close. When RAMP EMER switch is released, ramp shall stop and hold its position. If ramp system fails to operate properly go to task 7-3.15. TASK RESULT 9. Lift switch guard of RAMP EMER switch (3) and hold When RAMP EMER switch (3) is held in UP switch in UP position until ramp and door are fully position, ramp shall close in proper sequence closed. Place RAMP PWR switch (2) in OFF When RAMP EMER switch is moved to UP, position. ramp control valve handle (5) shall move to its UP position and ramp shall close with proper door extension. If ramp control valve (4) or ramp system fail to operate as described, go to task 7-3.15. END OF TASK Change 14 7-125

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