Rockwell Commander 112 - HYDRAULIC SYSTEM COMPONENTS; FUNCTIONAL TEST PROCEDURE

SECTION III
HYDRAULICS
MAINTENANCE MANUAL
ROCKWELL
COMMANDER
112/B/TC/TCA
Factory Production
Power Pack Internal
Model Effectivity Part No.
Pressure Settings
Remarks
UP DOWN
112 - 1 THRU 35
48823-1
1600-2000
500-800
SPARES - USE 795000-1 POWER PACK
NOTE: Internal Power Pack Pressures
112 - 36 THRU 380
48823-3, -5 1600-2000
850-1250
are· set at:
GEAR UP
- 1800- 2000 PSIG
GEAR DOWN
- 600-700 PSIG
112 - 381 THRU 430
48823-5
1800-2000
850-1250
SPARES
- USE 795000-1 POWER PACK
Power Pack Pressures are pre-controlled
EXTERNALL Y with pressure switches
set at:
GEAR UP
- 1425-1575 PSIG
GEAR DOWN
- 450-700 PSIG
112 - 431 THRU 499
795000-1 1800-2000 600-700 SPARES - USE 795000-1 POWER PACK
112B - 500 THRU 544
Power Pack Pressures are pre-controlled
112TC - 13000 THRU
EXTERNALL Y with pressure switches
13149
set at:
112TCA - 13150 THRU
GEAR UP - 1650 ! 50 PSIG
13194
GEAR
DOWN
- 500 i" 50 PSIG
112B - 545 & SUBS
795000-1
1700-2100
500-800
SPARES
- USE 795000-1 POWER PACK
112TCA - 13195 THRU
Power Pack Pressures are pre-controlled
13999
EXT ERNALL
Y with pressure switches
set at:
GEAR UP - 1650 :!- 50 PSIG
GEAR DOWN - 500 i" 50 PSIG
Figure 3-3. Hydraulic System Pressure Settings
q. Always perform landing gear operational check
when replacing landing gear hydraulic components.
r. Clean hydraulic actuating cylinder piston rods
and landing gear struts with a clean cloth moistened
in hydraulic fluid, at frequent intervals.
FUNCTIONAL TEST PROCEDURE
When maintenance has been performed on the hydraulic
system which necessitates an operational check of the
landing gear, jack aircraft as outlined in Section 11 and
perform landing gear operational check as outlined be-
low. Functional test procedures applicable to speCific
components of the hydraulic system are also incorpo-
rated in this section. Procedures contained in the pre-
ceding General Maintenance Practices must be accom-
plished after component repairs.
a. Connect an auxiliary dc power supply (50-amp
minimum) to positive terminal on battery relay loca-
ted on battery box assembly in aft fuselage area.
b. Apply a 10 pound load to nose gear axle to
simulate an air load condition (see Figure 3-7).
3-6
NOTE
Add 10 pounds of weight to the main gear
to simUlate an air load if the hydrauliC lines
have been removed or changed (see Figure 3-7) ..
c. Add MIL-H-5606 hydraulic fluid to hydraulic
power pack reservoir as necessary to maintain suffi-
cient fluid during test.
d. Check all electrical switches - OFF.
e. Check landing gear selector switch - DOWN.
f. Master battery switch - ON and keep it on for
the duration of test.
g. Place throttle lever in midposition.
h . Check for following conditions:
1. Gear down indicator - ILLUMINATED.
2. Red gear warning indicator - EXTIN-
GUISHED.
3. Gear warning bell - SILENT.
HYDRAULIC SYSTEM COMPONENTS
ACTUATING CYLINDERS
The hydraulically operated actuating cylinders are
attached to the drag brace and trunnion on the nose
gear, and side brace and trunnion on the main gears.
One port of each cylinder is connected to the gear up
hydraulic line, and the remaining port to the gear
down line. Hydraulic fluid, under pressure, is di-
rected to the actuator cylinders by the gear selector
switch located on the instrument panel. During the
actuating cycle the gear up and gear down hydraulic
lines act as either pressure or return lines, depend-
ing on the gear position selected.
Change 2
Copyright Commander Owners Group 2013 All Rights Reserved
**unofficial copy**