Take care that accelerometer cable cannot fall into
the shaft or couplings.
e. Pass accelerometer cable between tail boom and drive shaft if drive shaft cover is not installed.
Connect accelerometer cable to the DAU receptacle marked ACC4.
PROCEDURE 3: OPTICAL RPM SENSOR INSTALLATION
a. Remove the two screws at the base of the tail rotor gearbox just below the oil level sight glass, see figure 7.
b. Mount optical RPM sensor mounting bracket (29198600) at the base of the gearbox using the two screws. The
rectangular hole should be toward the left side of the aircraft.
c. Mount optical RPM sensor (29314700) to the bracket, facing the tail rotor.
d. Route the optical RPM sensor cable the same as the accelerometer cable, procedure 2.
e. Connect the optical RPM sensor cable to the DAU receptacle marked TACHO 2.
If there is any tape remaining from previous balance
routines, this must be completely removed to ensure a
clear and accurate tachometer signal to the DAU.
f. Place a single, 3-inch strip of reflective tape on the inside of one of the tail rotor blades, figure 8, at the
approximate location of the beam from the optical RPM sensor.
g. Proper alignment of the tape can be verified by applying AC power to the DAU and rotating the tail rotor until the
taped blade passes in front of the optical RPM sensor. When the tape is in line with the optical RPM sensor the
red LED on the back of the sensor will flash.
PROCEDURE 4: PERFORM TAIL MEASUREMENT
a. Operate aircraft at appropriate percentage.
b. Turn on DAU.
c. Turn on CADU.
d. Press QUIT on the CADU until all selections are undefined.
e. Use cursor keys to highlight Aircraft Type, then press DO.
f. Use cursor keys to highlight OH-58A/C, and then press DO.
g. Tail Number is highlighted. Press DO.
h. Use cursor keys to highlight a tail number or enter a new tail number (up to seven characters), then press DO.
i. Flight Plan is highlighted. Press DO.
j. Use cursor keys to highlight TAIL. Press DO. Enter the Measure mode by pressing F1. Verify that Test State
FPGTL is highlighted.
k. Press DO when the aircraft is stable at the highlighted selection. Re-verify that the aircraft is at the required
Test State and press DO again. The AVA will acquire balance data and return to the selection menu.
l. After the measurement is completed, press DO on Finish, then press DO on Diagnostics. If measurements are
within specified limits, press QUIT to Main Menu.
m. If measured values exceed specification, press DO to enter the DIAGS mode. Evaluate the percentage
improvements obtainable through further corrective actions and the ability to perform the corrections.
o. Perform all desired corrections displayed on the diagnostic screen. Check to ensure that all screens of a
multiple screen solution have been displayed.
p. If alterations of these corrective actions are desired, use the Edit Adjustables and Edit Defaults options and use
all of the edited adjustments.
q. After corrections are made, repeat procedure 4 to verify the corrections.