TM 1-1520-238-T-4
Change 9
5–51
5–21.
FLIGHT CHECK AND ADJUSTMENT USING AVA EQUIPMENT (cont)
5–21
Add Weight #2
(Subtract Weight #4)
270
90
167
347
1.0 ips
.5 ips
257
77
0
180
M58-0295-8
Add Weight #1
(Subtract Weight #3)
Subtract Weight #2
(Add Weight #4)
Subtract Weight #1
(Add Weight #3)
FPG
.017 ips
HOV
.019 ips
LAT effect from 52 g of Weight
FPG
.037 ips
HOV
.042 ips
LAT effect from 113 g of Weight
Figure 5–23.
AH–64 Lateral Effect for Weight Changes
c. INTERPRETING RESULTS AND MAKING CORRECTIONS
(1) AVA will recommend pitch link, weight, and tab adjustments in the diagnostics for FLIGHT. The default
solution can be utilized, but it is recommended that other solutions be obtained by using the EDIT ADJUSTABLES
and EDIT DEFAULTS, and compare the predicted vibration levels with the default solution. By utilizing these
options you will usually reduce the number of corrections, save time and still bring the vibration to acceptable
levels. The other solutions are described in detail later in this section. The following is an explanation of the
method that the AVA uses to obtain the default solution:
When calculating the corrections, AVA only considers the present vibration environment. Previous
flights have no effect on the calculation of adjustments.
AVA’s goal is to reduce overall vibration.
WEIGHT: AVA recommends a weight correction based on ground and hover lateral
measurements and pitch link adjustments if they are necessary. This adjustment is usually small,
because this should have been minimized in the INITIAL flight plan. If the weight adjustment is
small the usual procedure is to toggle WEIGHTS off in the EDIT ADJUSTABLES and press DO to
obtain a new solution, or to reduce the number of corrections (see custom solutions below), which
will eliminate small corrections and utilize more effective corrections. If weight is not adjusted
during in–flight rotor smoothing and if at the end of rotor smoothing the balance needs to be
adjusted, this can be accomplished by performing an INITIAL measurement that no adjustments
were performed on and toggle everything off except weight. This will have little or no effect on the
vertical vibration levels in flight.
