DO stop making corrections when within acceptable levels. The diagnostic algorithm will always calculate a
correction even though the airframe levels are within spec. At low vibration levels, the predicted corrections
will generally improve track, but not make significant vibration level improvements.
DO use the Edit Adjustables to limit the number of corrections. The diagnostic routine will calculate
corrections for all locations not constrained by the aircraft setup file. Many times by using this editor, you can
reduce the number of corrections to be made and still reach the desired limit. If this is the case, use the editor
and put an N for the particular correction and review the predicted response. If the predicted response is
within limits, follow the new set of corrections.
DO make the corrections properly. The diagnostics won't work if the corrections are installed improperly.
DO monitor the vibration/track convergence. Generally there should be steady improvements in vibration and
track levels for each round of corrections. If this is not happening, there may be other abnormal mechanical
conditions that are preventing a proper solution. Improvements of greater than 50% per round of
adjustments should be anticipated for rough aircraft.
DO compare the previous predicted response vs. the actual response. They should generally be close. If
they are drastically different, there may be an abnormal mechanical condition that will prevent the diagnostics
from working properly.
DO monitor the track spread. Even though many of the diagnostic aircraft setups weigh vibration
improvements more importantly than track spread, if the calculated correction results in a large track spread
there may be other abnormal mechanical faults.
DON'T keep making corrections without an improvement in levels. When all else fails it may be time to do a
flat track on the ground and start over.
DON'T follow the recommendations blindly. The operator is still responsible for the airframe maintenance,
and the operator's judgment will make the AVA an effective tool. If some of the corrections don't make sense,
don't implement them. Corrections that don't make sense could be caused by a mechanical fault in the rotor
that is influencing the rotor diagnostics.
The diagnostics capability of the AVA allows the simultaneous prediction of weight, pitch link, trim tab and other
adjustments for configured aircraft. The advanced measurement capability along with a sophisticated diagnostic
algorithm results in a system that typically corrects normal rotor track and balance problems within a few flights.
The Test States, measurements, and diagnostics are custom tailored for each airframe by the aircraft
configuration file. The diagnostic algorithm utilizes all the track and vibration measurements made at each of the
test conditions to come up with an optimum solution, which minimizes vibration and track over the complete
operating envelope. Weighting factors within the aircraft configuration file allow a trade off between track and
vibration levels allowing specific test conditions or types of vibration to be corrected at the expense of other test
conditions or vibration levels.
END OF WORK PACKAGE