Rockwell Commander 112 - Emergency Extension Valve; Miscellaneous Hydraulic Components

ROCKWELL
COMMANDER
112/B/TC/TCA
MAINTENANCE MANUAL
SECTION III
HYDRAULICS
GEAR RETRACTED
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o
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X2388
/
GEAR EXTENDED
~--.
ATTACH TEST HYDRAULIC
PRESSURE GAGES TO THESE
LINES
VIEW OF HYDRAULIC LINES
LOOKING OUTBOARD
IN LEFT
WHEEL WELL
Figure 3-6. Hydraulic Gear Lines
REMOVAL
a. Master battery switch - OFF.
b. Disconnect two electrical leads and label for
identification. Tape ends of electrical leads to prevent
shorting.
c. Disconnect ground wire from airframe.
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d. Screw vent port screw down tight to prevent
hydraulic fluid leakage 0
e. Disconnect hydraulic lines from hydraulic power
pack. Cap lines to prevent contaminationo
f. Remove hydraulic power pack by removing four
attaching bolts, washers, grommets, bushings and nuts.
INST ALLATION
a. Position hydraulic power pack in place and attach
with bolts, washers, grommets, bushings and nuts ~
b. Connect hydraulic lines to hydraulic power pack.
c. Connect ground wire to airframe.
d. Connect two electrical leads.
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e. Clear vent port by backing screw and washer
out to allow a 0.06 inch minimum clearance between
power pack boss and bottom of rubber washer seal.
EMERGENCY EXTENSION VALVE
An emergency extension valve is located at the left
forward side of the center console. This valve by-
passes hydraulic fluid from the upside of the actuators
(which form the hydraulic uplock) directly to the reser-
voir. The gears drop by gravity, and the piston locks
mechanically engage. The gears cannot be raised, and
the piston down lock cannot become disengaged.
EMERGENCY EXTENSION FREE- FALL TEST. With
the aircraft on jacks, retract the landing gear and
place the throttle in midposition. Apply a five and
Change 4
one-half pound weight to ,the axle of the nose landing
gear to simulate an air load (see Figure 3-7).
a. Disconnect hydraulic power pack unit at electrical
quick disconnect.
b. Landing gear selector switch - DOWN.
c . Push landing gear emergency valve control knob
DOWN and hold. Valve and control knob is located on
left forward side of center console (see Figure 6-5).
d. Check for following:
e.
1 . Gear unsafe red indicator light on.
2 . Warning bell should not sound.
3. Gear free falls in a positive motion.
4. Gear safe green indicator lights on within
14 seconds after pushing emergency control knob.
5. Gear unsafe red indicator light off.
6. Return emergency control knob to its
normal pOSition.
7. Master battery switch - OFF.
8. Reconnect hydraulic power pack to air-
craft electrical system.
9. Master battery switch - ON.
Return aircraft to normal configuration.
MISCELLANEOUS HYDRAULIC COMPONENTS
Hydraulic fluid (MIL-H-5606) is also used in other
components of the aircraft that are not functionally
tied to the hydraulic power pack. These components
. are the master brake cylinders, nose shimmy damp-
ener, nose and main gear struts and wheel brakes.
All of the components have their own self-contained
reservoirs except the wheel brakes which, on Model
112 are supplied from the master brake cylinders.
On all other Models, the brake cylinders are supplied
fluid from a reservoir located forward of the engine
firewall. Detailed description and servicing is con-
3-11
Copyright Commander Owners Group 2013 All Rights Reserved
**unofficial copy**