b.) If all seven conditions have not been completed and no additional data is to be taken, press QUIT to exit the
measurement screen. Highlight Save and Exit and press DO. On the Main Menu, verify that the flight ID
corresponds to the flight for which a solution is desired and press F3 DIAGS.
BEFORE ENTERING DIAGNOSTICS:
a. Before entering diagnostics it may be beneficial to view the in flight vertical reading on the polar plot and the
flight track trend. By doing this before entering diagnostics, it will give a good indication of what will be
required to smooth the aircraft. Figure 7 illustrates a polar plot display of the flight vertical vibration readings
from the AVA.
Figure 7. Polar Plot Display
b. By viewing the figure 7 and the AH-64 coefficient polar chart for vertical vibration at the end of this appendix,
this clearly shows that blade 1, blade 3, or both will require adjusting to move the vibration points towards the
center. To move the vibration points towards center for this example would require blade 1 to be tabbed down
(or pitch linked down) or blade 3 to be tabbed up (or pitch linked up). To verify this further it helps to view the
track data. Figure 8 illustrates the track trend for this example from the AVA.
Figure 8. AVA Track Trend
c. The polar chart showed that either blade 1 or 3 may need to be adjusted to move the vibration to the center,
and this track trend shows that blade 1 is the blade that needs to be adjusted. Adjustments should not be
made based on this track trend, the information from both the polar chart and the track trend should be used to
make smart decisions when running AVA diagnostics. This is emphasized here by the fact that if adjustments
were based on this track trend alone, blade 2 might also be adjusted, which will actually increase the vertical
vibration as shown in figure 9.