TM 1-6625-724-13&P
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TASK 10 - ISOLATING IRREGULAR/UNUSUAL VIBRATIONS
PROCEDURE 1: EQUIPMENT INSTALLATION
a.
Remove AVA equipment from transport case. Check for possible damaged equipment and frayed cables.
b.
Install DAU in canvas carrying case.
c.
Place DAU in left or right crew seat with connectors facing up and secure DAU using aircraft shoulder and lap
belts and canvas strap D-rings. If no seats are installed, the DAU may be secured to the D-rings found on the
aircraft cabin floor.
d.
Connect power cable (29104700) to aircraft's 28 Vdc utility receptacle at station 293, right side, on cabin
ceiling and to DAU receptacle marked 28 Vdc.
e.
Place CADU in aircraft. Connect CADU to DAU cable (29325601) to CADU and to DAU receptacle marked
CADU.
PROCEDURE 2: ACCELEROMETER INSTALLATION
NOTE
Data can be acquired from up to four accelerometers to
assist in isolating/irregular or unusual vibrations.
a.
Mount/install accelerometer (28110900) (found in the basic kit) anywhere on the airframe that an irregular or
unusual vibration is detected.
b.
Connect accelerometer cables (found in the basic kit) from accelerometer to the DAU receptacle marked
ACC1, ACC2, ACC3, and/or ACC4.
PROCEDURE 3: PERFORM PROBES MEASUREMENTS
a.
Operate aircraft at desired flight condition. This should be the RPM or airspeed at which the vibration is
strongest.
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 UH-60, 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 digits), 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 Test State ACC1 is highlighted.
l.
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. The flight plan will measure data on one channel
at a time. Perform this operation each time a measurement is completed and another Test State is
highlighted. The AVA will acquire vibration data at each selected Test State and then 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 then press DO. Review each of the
spectrums measured for any unusual vibrations.
o. Make appropriate logbook entry if necessary and remove test equipment.
END OF WORK PACKAGE
