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TM 1-6625-724-13&P
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TASK 6 - ISOLATING IRREGULAR/UNUSUAL VIBRATIONS
PROCEDURE 1: EQUIPMENT INSTALLATION
a. Remove AVA blade tracking equipment from transport case. Check for possible damaged equipment and
frayed cables. Figure 1 is the typical AVA test setup configuration.
b. Install DAU in the canvas carrying case.
c. Place DAU in the back seat with the connectors facing up and secure DAU using lap and shoulder belts and
canvas straps and D-rings.
d. Connect the UH-1 dc power adapter cable (29312800), figure 2, to the heater blanket receptacle and to the 10-ft
power cable (29104700).
e. Connect power cable to the DAU receptacle marked 28 Vdc.
f. Install CADU in aircraft. Connect CADU-to-DAU cable (29325601) to CADU and to DAU receptacle marked
CADU.
PROCEDURE 2: ACCELEROMETER INSTALLATION
a. Mount/install accelerometer (28110900) anywhere on the airframe that an irregular or unusual vibration is
detected.
b. Connect accelerometer cable (29105600) from accelerometer to the DAU receptacle marked ACC1, ACC2,
ACC3, and/or ACC4. The flight plan will measure data on one channel at a time.
PROCEDURE 3: PERFORM PROBES MEASUREMENTS
a. Operate aircraft at desired RPM.
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 UH1 or UH1CRB, 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 PROBES. Press DO.
k. Enter the MEASURE mode by pressing F1. Verify that ACC1 is selected.
I. Press DO when the aircraft is stable at the highlighted selection. Verify that the aircraft is at the required Test
State (ACC1, ACC2, ACC3, or ACC4) and press DO again. Perform this operation each time a measurement
is completed and another Test State to be measured is highlighted. The AVA will acquire vibration data and
return to the selection menu.
m. After the last measurement is completed, press DO on Finish, then press DO on Main Menu.
n. Enter the Display mode by pressing F2. Select One Test State and press DO. Review each of the spectrums
measured for any unusual vibrations.
o. When finished, remove test equipment and make appropriate log entries.
END OF WORK PACKAGE
