MAIN ROTOR 4/REV VIBRATION IS WITHIN LIMITS

TASK 4 - MAIN ROTOR ROLL/VERTICAL IN-FLIGHT TUNING

PROCEDURE 3: H-60 SERIES AIRCRAFT TRIM TAB ADJUSTMENTS

TM-1-6625-724-13P Aviation Vibration Analyzer Manual
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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.

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