S e c t i o n I l . O P E R A T I O N U N D E R U S U A L C o n d i t i o ns
3-3. Preliminary Starting Procedure.
Refer to Figure 2-1 and proceed as follows:
a. On Test Box front panel, set all toggle switches OFF, and
set TRIM COIL SELECT switch to BOTH.
Position Test Fixture or, bench so that Pilot As-
sist module relief valve cannot vent on working
personnel during overpressure conditions.
Make certain that hydraulic test stand uses hy-
draulic fluid consistent with each operating en-
b. Connect hydraulic lines from deactivated hydraulic test
stand to PRESSURE (AN No. 4) and RETURN (AN No. 6)
ports at rear of Test Fixture manifold.
c. Connect plugs of four Test Box cables to appropriate
receptacles of Pilot Assist Module (on Test Fixture) as follows:
Pilot Assist Module Component
Pitch/Trim shutoff valve
SAS pressure switch
SAS shutoff valve
Boost shutoff valve
d. Remove cables from stowage compartment at rear pan-
el of Test Box.
e. Connect ac power cable (part No. 70700-20646-042) be-
tween receptacle J2 on test box and 115 vac, 60 Hz power
f. Connect DC power cable (part No. 70700-20633-041) be-
tween receptacle J1 on test box and 28 vdc power source.
g. Wipe all self-sealing hydraulic couplings clean of foreign
materials using low-lint cloth (item 4 App D).
h. Install servo assembly to be tested on appropriate track
guide on Test Fixture base, and slide servo toward manifold
to engage self-sealing hydraulic couplers.
When testing a pilot assist hydraulic module, re-
fer to paragraph 4-17 for instructions on removal
and installation from test fixture.
i. Bolt servo assembly to be tested to Test Fixture manifold.
j. Install 0-4000 psi direct read pressure gages in Test Fix-
ture ports marked TRIM and BOOST.
For roll, yaw, and collective servo assemblies, con-
) between test
nect cable (part No. 70700-20682-042
box J3 and servo under test. Use cable (part No.
70700-20682-041) to test pitch trim servo.
k. Activate hydraulic test stand, and set fluid pressure for
3000 psi at 2 gpm.
1. Check all hydraulic coupling points for leaks.
3-4. Operating Procedure.
Refer to Figures 3-1, 3-2, Table 3-1, and manual TM
551520-237-23-3 for detailed test and nulling procedures for
the flight control system servo assemblies.
Pilot Assist Hydraulic Module assembly
Collective Servo assembly
Roll SAS assembly
Yaw Boost Servo assembly