TM 1-6625-724-13&P
0071 00
0071 00-33
TASK 4 – BALANCE TAIL ROTOR
a. Operate the aircraft at full operating rpm, with the main rotor at flat pitch (full down collective).
b. Turn on DAU.
c. Turn on CADU.
d. Press QUIT until the Main Menu appears. Highlight Aircraft Type and press DO. Highlight the appropriate script
file (described under Main Rotor Track and Balance section) and press DO.
NOTE
If main rotor measurements are not being done at the
same time, the tail rotor measurement is independent of
the main rotor accelerometer configuration. If tail rotor
balance is to be performed at the same time as main
rotor ground track and balance, utilize whichever script
file is being used relative to “SPU interface” or “external
wiring” for the main rotor work.
e. Tail number is highlighted. Press DO. Use cursor keys to highlight an existing tail number or enter the numbers
from the keypad and press DO.
f.
Flight Plan is highlighted. Press DO. Highlight tail and press DO.
g. Initiate measurement mode by pressing F1 MEASURE.
h. fpgtl is highlighted. Press DO to initiate measurement, then DO again when the aircraft is steady at the desired
condition. AVA will indicate Measuring and will display the rotor speed. Verify that the aircraft is at required Test
State.
i.
Once the measurement has been successfully acquired, the AVA will exit the measurement screen automatically.
Press DO on Finish.
j.
Highlight Diagnostics, and then press DO.
PROCEDURE 5: PERFORM TAIL ROTOR BALANCE DIAGNOSTICS
WARNING
Ensure proper blade weight retaining hardware is
installed in the tail rotor blades.
WARNING
NEVER remove ALL of the weight from the tail rotor
blade tips in an attempt to “zero out” the balance for
a new starting point. Doing so may cause severe tail
rotor vibration and result in aircraft damage. In
addition to being used for dynamic rotor balance,
tail rotor tip weights serve the important purpose of
maintaining the design static spanwise mass
moment of the blade and were initially installed by
the manufacturer. Efforts should be made to make
the minimum disturbance to those weights over the
course of tail rotor dynamic balance maintenance
exercises.
