TM 55-1520-240-T
7-3.4 CARGO RAMP AND DOOR MANUAL OPERATIONAL CHECK (Continued)
7-3.4
TASK
RESULT
TASK
RESULT
1.
Check apu start accumulator gage (1).
2.
Turn EMERG UTIL PRESS valve (2) to OPEN.
3.
Set RAMP control valve handle (3) to DN. When ramp is level with
cabin floor, set handle to STOP.
4.
Turn EMERG UTIL PRESS valve (2) to NORMAL.
5.
Apply electrical and hydraulic power.
6.
Check that UTIL SYS CONT circuit breaker (4) is
closed.
7.
Set RAMP switch (5) to ON. On aircraft without [65], set RAMP
switch (5) to ON. On aircraft with [65], set RAMP PWR switch (5.1) to
ON.
8.
Turn pin (6) on sequence valve (7) to horizontal position.
CAUTION
Do not cycle cargo door with ramp in full up position. Damage
to door and fuselage will occur.
9.
Set RAMP CONTROL valve handle (3) to DN. When ramp is fully
down, set handle to UP.
10.
Move RAMP CONTROL valve handle (3) to DN. When ramp is at mid
position, move handle to STOP.
11.
Turn pin (6) on sequence valve (7) to vertical position.
12.
Pull up and hold MANUAL OPER knob (8) on sequence valve (7).
Gage (1) shall indicate at least 2500 psi. If it does not, use hand pump
to charge accumulator.
Ramp shall move down and stop about 10 inches from fully closed
position. Cargo door shall then retract into ramp. Ramp shall continue
to move down and stop when RAMP CONTROL handle (3) is set to
STOP. If ramp does not move, go to task 7-3.5. If cargo door does not
retract, go to task 7-3.6.
If UTIL SYS CONT circuit breaker (4) is open, close it. If it opens again,
go to task 7-3.7.
Ramp shall move full down with handle (3) at DN. Ramp shall move
full up with handle at UP. If ramp does not move up, go to task 7-3.8. If
ramp moves up and down but is sluggish, bleed ramp activating
cylinders. If door moves, replace sequence valve (7).
Ramp shall move to mid position and remain there after handle (3) is
moved to STOP. If ramp creeps up or down, go to task 7-3.12.
Cargo
door
shall
extend.
If
it
does
not,
go
to
task
7-3.9.
13.
Release MANUAL OPER knob (8).
14.
Set RAMP switch (5) to OFF. On aircraft without [65], set RAMP
switch (5) to OFF. On aircraft with [65], set RAMP PWR switch
(5.1) to OFF.
15.
Set RAMP CONTROL valve handle (3) to UP.
16.
Set RAMP CONTROL valve handle (3) to STOP. On aircraft
without [65] set RAMP switch (5) to ON. On aircraft with [65] set
RAMP PWR switch (5.1) to ON.
17.
Set RAMP CONTROL valve handle (3) to DN. When ramp is fully
down set handle to UP.
18.
Press and hold knob (9) on door override valve (10). Set RAMP
CONTROL valve handle (3) to DN. When ramp is at mid position, set
handle to STOP.
19.
Release knob (9).
20.
Set RAMP CONTROL valve handle (3) to UP. When ramp is closed,
set handle to STOP.
21.
On aircraft equipped with [65] check operation of emergency
extension system per task 7-3.4.1
22.
Remove hydraulic power and electrical power. 23. Turn UTILITY
RESERVOIR DEPRESSURIZE valve (11) to OPEN. Press
depressurization valve (12) on apu start module (13).
24.
Turn UTILITY RESERVOIR DEPRESSURIZE valve (11) to
NORMAL.
25.
Set
RAMP
CONTROL
valve
handle
(3)
to
DN.
Cargo door shall retract. If it does not, replace sequence valve (7).
Ramp shall not move up. If it does, go to task 7-3.10.
Ramp shall move full down with handle (3) at DN. Ramp shall move up
with handle at UP and stop approximately 8 inches from full closed
position. Cargo door shall then extend. Ramp shall then move up and
close. If cargo door does not extend, go to task 7-3.9. If ramp does not
stop before closing, go to task 7-3.11.
Ramp shall move down to mid position with cargo door
extended.
Cargo door shall retract. If it does not, replace door override valve (10).
Utility system shall depressurize.
Ramp shall not move. If it does, adjust actuating cylinders.
FOLLOW-ON MAINTENANCE:
TM 55-1520-240-23:
Battery disconnected.
Electrical power off.
Hydraulic power off.
END OF TASK
Change 14 7-124.1
