TM 1-1520-238-T-4 5–42 Change 9 5–20. INITIAL CHECK AND ADJUSTMENT USING AVA EQUIPMENT (cont) 5–20 NOTE The reason that it is not recommended to adjust pitch links for hover track is that the flight adjustments should cause the hover track to fall within specified limits. (2) Once ground and hover balance is adjusted to acceptable levels, proceed to paragraph 5–21, Flight Track and Adjustment. Do not continue making adjustments to fine tune for INITIAL program. If vibration levels are within limits normal procedure is to proceed to flight, because adjustments for flight will affect these levels. (3) If a weight adjustment is required, go to step e. (4) If a pitch link adjustment is required, go to paragraph 5–19, step c. d. COMPARING MOVES BETWEEN FLIGHTS (1) Compare vibration from one measurement to next (mainly to ensure that aircraft is responding in a normal manner). For INITIAL flight plan lateral readings should be trended. To trend more than one data set, perform the following: With latest Flight ID picked, enter the display mode by pressing F2. Select Trend Flights and press DO. Select desired channel to trend (either FPGLAT or HOVLAT) and press DO. Enter number of test states to trend (the easiest to understand is just trend the last two flights by entering 2, this will trend the most current flight with the previous flight), then arrow to Draw Axis and Change to NO by pressing the “right arrow” (this will make the polar chart easier to read), and then press DO. (2) This will display vibration trend from the latest flight with previous flights on a polar chart. This process is displayed in Figure 5–17. One Test State Complete Flight View Limits Summary Displays Display Mode Trend Flights [ DO ] Select Options FPG100 FPG100 Hover 1R LAT 1R VERT 1R VERT DISPLAYS DO–Select QUIT – Exit Hover 1R LAT Enter the number of tests to show on the polar plot at one time. No. of Test: 2 [UP] [LEFT] [DO] & & Save & Exit [DOWN] [RIGHT] Arrows Arrows Draw Axis = NO Entry Form 0.50 AH64 24238 CURRENT 14:24:00 28 AUG 96 ID FLT AMP [ips] PHASE [deg] Hover 1R VER A B A B CURRENT 14:12 0.03 0.32 35.69 160.96 M58-0295-9 Figure 5–17. Polar Chart Trend