TM 1-1520-238-T-4
5–38
Change 9
5–19.
GROUND TRACK AND ADJUSTMENT USING AVA EQUIPMENT (cont)
5–19
b. PERFORM GROUND TRACK (GNDTRK) MEASUREMENT
(1) Press QUIT on CADU until all selections are undefined.
(2) Use cursor keys to highlight Aircraft Type, then press DO.
(3) Use cursor keys to highlight AH64, then press DO.
(4) Tail Number is highlighted, then press DO.
(5) Use cursor keys to highlight a tail number or enter a new tail number (up to seven digits), then press
DO.
(6) Flight Plan is highlighted, then press DO.
(7) Use cursor keys to highlight GNDTRK, press DO.
(8) Enter the MEASURE mode by pressing F1. Verify that test state Fpg100 is highlighted.
NOTE
If tracker is pointed towards the sun, AVA might give a tracker error. To
avoid possible delays while obtaining data, always try to point tracker away
from the sun.
(9) Press DO when aircraft is stable at highlighted selection. Reverify that aircraft is at required test state
and press DO again. AVA will acquire track data and return to selection menu.
(10) After measurement is completed, press DO on “finish”, then press DO on “diagnostics”. If
measurements are within specified limits, press QUIT to return to main menu and perform paragraph 5–20, Initial
Check and Adjustment.
(11) If measured values exceed specifications, press DO, perform pitch link corrections (step c) according
to AVA, or utilize the EDIT ADJUSTABLES as follows:
(a) Track can be adjusted to any one blade (i.e., designated target) by using the EDIT ADJUSTABLES
from the AVA diagnostic menu and toggling off the blade (target) that you want to adjust to. Example: If blade four
is high and you want to adjust other blades up to four, just toggle off blade four in the EDIT ADJUSTABLES and
press DO and AVA will give the solution to adjust other blades to blade four. The reason this is mentioned is that
some users in the field have used dual engine torque readings to adjust track. This is done to prevent a large
autorotation adjustment later during track and balance. The following are examples of this method.
If torque is less than 15%, adjust blades up to highest blade by toggling off highest blade and
obtaining a solution.
If torque between 15% and 20%, use AVA recommended default solution to adjust track to the
mean of the blades.
If the torque is greater than 20%, adjust blades down to lowest blade, by toggling off lowest blade
and obtaining a solution.
(12) Repeat steps (8) thru (11) until track is within limits, then proceed to paragraph 5–20.
NOTE
One flat is approximately 0.40 INCH of track.
