0069 00
TM 1-6625-724-13&P
0069 00-16
measurement is completed and another Test State is highlighted. The AVA will acquire track and vibration
data at each Test State and then return to the selection menu.
j.
After the last measurement is completed, press DO on Finish, then press DO on Diagnostics.
k. The first screen indicates the status of the absorbers. If absorbers are tuned, expect to see the following
message:
MAIN ROTOR 4/REV VIBRATION
IS WITHIN LIMITS.
---------------------------------------------------------------------
ABSORBER TUNING CAN BE CONSIDERED
COMPLETE. HOWEVER IF CABIN ABSORBER IS
NOT TUNED TO 100%Nr, ABSORBER TUNING IS
NOT OPTIMUM. IT IS RECOMMENDED THAT
CABIN ABSORBER BE TUNED TO 100%Nr FOR
BEST MAIN ROTOR 4/REV VIBRATION RESULTS.
NOTE
The cabin Box Spring Absorber is tuned to 100.5%.
l.
After rotor smoothing is completed and if absorbers are in need of tuning, proceed to task 7.
m. If rotor 1/REV measurements are within specified limits, press QUIT to Main Menu. Remove test equipment.
NOTE
The vibration goals are: A+B at Hover, 80 Kts, 120 Kts
and 145 Kts <0.25 ips. Also, the A-B goal at all points is
0.20 ips. If all goals are achieved, no adjustments are
necessary and the rotor track and balance is complete.
n. If measured values exceed manufacturer's desired levels, press the DO key to enter the DIAGS mode.
Evaluate the percentage of improvements using “View Predictions” to determine if the corrective action
suggested on the “View Corrections” page is sufficient to lower vibration to acceptable levels. Perform all
corrections displayed on the correction screens. Check to ensure that all screens of multiple page solutions
have been performed. If alterations to these corrective actions are desired, use the EDIT ADJUSTABLES and
EDIT DEFAULTS options. Do not use a partial set of the adjustments. See procedure 3 for trim tab
adjustments.
o. After corrections are installed, fly aircraft and repeat task 4 to re-check the 1/REV vibrations through the
required flight conditions.
p. If last flight does not sufficiently improve rotor vibration, trend the flight data.
1. Press QUIT until the Main Menu is displayed.
2. Press F2 “Display”.
3. Select “Trend Flights” and press DO.
4. Select the appropriate accelerometer channel and test condition for the desired data to be viewed.
5. Change the number 4 to 2 in the “# of Test” column and change “Draw Axis” from YES to NO then press
DO.
6. View the polar chart to determine if the vibration went towards the center or away from the center.
7.Perform corrective actions deemed necessary to correct this condition, i.e. adjustments installed
backwards,incorrect blade color coding, worn components etc.
q. Perform task 4 again until rotor vibrations are below vibration goals outlined in the note above.
