TM 55-1520-240-T
3 - 1 . 3 P R O X I M I T Y S W I T C H O P E R A T I O N )
3-1.3
INITIAL SETUP
Applicable Configurations:
W i t h o ut
Tools:
Aircraft Mechanic’s Tool Kit,
NSN 5180-00-323-4692
Jack 1214-151 or equal
Materials:
None
Personnel Required:
Avionic Mechanic
Medium Helicopter Repairer (2)
References:
TM 55-1520-240-23
Equipment Condition:
Battery Connected
Electrical Power On
Hydraulic Power On
Aft Landing Gear Access Panels Open
Flight Controls Closet Acoustic Blanket Removed
Flight Controls Closet Panel Open
TASK
RESULT
TASK
RESULT
CHECK CIRCUIT BREAKERS
1. Check that following circuit breakers in
NO. 1 PDP are closed:
AC
AFCS NO. 1 (1)
NAV COPLT VGI (2)
DC
AFCS NO. 1 (3)
2. Check that following circuit breakers in
NO. 2 PDP are closed:
AC
AFCS NO. 2 (4)
NAV PILOT VGI (5)
DC
AFCS NO. 2 (6)
NAV CONT VGI (7)
CHECK LEFT PROXIMITY SWITCH
If any circuit breaker ( 1 through 3) is open, close it.
If AFCS NO. 1 circuit breaker (1) opens again, go to
task 11-3.4.
If NAV COPLT VGI circuit breaker (2) opens again,
refer to TM 11-1520-240-20.
If AFCS NO. 1 circuit breaker (3) opens again, go to
task 11-3.6.
If any circuit breaker (4 through 7) is open, close it.
If AFCS NO. 2 circuit breaker (4) opens again, go to
task 11-3.10.
If NAV PILOT VGI circuit breaker (5) opens again,
refer to TM 11-1520-240-20 for troubleshooting in-
formation.
If AFCS NO. 2 circuit breaker (6) opens again, go to
task 11-3.11.
If NA\/ CONT VGI circuit breaker (7) opens again,
refer to TM 11-1520-240-20 for troubleshooting in-
formation.
3. Set SYSTEM SEL switch (8) to 1.
4. Position observer at flight controls closet
to watch output shafts (9 and 10) of DASH
actuator (11).
5. Move pilot’s pitch and roll control stick
Output shaft (9) on DASH actuator (11) shall not
grip (12) forward.
move. If it moves, go to task 11-3.15.
6. Return pilot’s pitch and roll control stick
grip (12) to neutral.
7.
8.
9.
10.
Keep movement to minimum
while aircraft is on jack. Personnel
injury and damage to equipment
can result if aircraft should slip off
jack.
Raise left aft end of helicopter with jack
(13) but do not install static lock (14).
Jack helicopter until wheel (15) is off ground
and shock strut (16) is fully extended.
Move pilot’s pitch and roll control stick
Output shaft (9) on DASH actuator (11) shall move.
grip (12) forward.
If it does not, check proximity switch adjustment. If
adjustment is correct, go to task 11-3.15.
Return pilot’s pitch and roll control stick
grip (12) to neutral.
Lower jack (13) until clear of helicopter and
remove it.
CHECK RIGHT PROXIMITY S WITCH
11.
12.
13.
Set SYSTEM SEL switch (8) to 2.
Repeat steps 4, 5, and 6 above.
Output shaft (10) on DASH actuator (11) shall not
move. If it moves, go to task 11-3.15.
Repeat steps 7 through 10 above, except
Output shaft (10) on DASH actuator (11) shall move.
jack right aft end of helicopter.
If it does not, check proximity switch adjustment. If
adjustment is correct, go to task 11-3.15.
FOLLOW-ON MAINTENANCE:
TM 55-1520-240-23
Close aft landing gear access panels.
Close flight controls closet and install blanket.
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