TASK 3-TRACK AND BALANCE MAIN ROTOR ON THE GROUND
The preferred method of tracking the OH-58D is tracking it with the MMS installed. Removing the sight and working
the rotor until smooth and then reinstalling the sight is considered an obsolete method and could result in high
vibration levels at idle RPM when the sight is reinstalled. Working the rotor with the sight installed and using the OH-
58DM script file will preclude from having high vibration levels at Idle RPM.
When using the INT-SG flight plan in the OH-58D setup file, the correct procedure is to obtain a track picture of less than
0.2 inches at both 65%_NR and 35%_TQ test conditions. The diagnostics will use the main rotor pitch links to obtain a
track not greater than 0.2 inches at 65% NR and then use the outboard trim tabs to correct for less than 0.2 inches track
change from 65%_NR to 35%_TQ. It will also give a correction to reduce fore/aft vibration at the 35%_TQ test condition.
When using the INT-SG flight plan in the OH-58DM setup file, the correct procedure is to obtain a track picture of less
than 0.2 inches at both 65%Nr and 35% TQ test conditions. The diagnostics will use the main rotor pitch links to obtain
a track not greater than 0.2 inches at 65%Nr and then use the outboard trim tabs to correct for less than 0.2 inches track
change from 65%Nr to 35% TQ. It will also give a correction to reduce fore/aft vibration at the 65%NrC test condition.
PROCEDURE 1: PREPARATION
Perform task 2, Flat Track Main Rotor on the Ground.
PROCEDURE 2: PERFORM INITIAL MEASUREMENT
a. Press QUIT on the CADU until all selections are undefined.
b. Use cursor keys to highlight Aircraft Type. Press DO.
c. Select aircraft type OH-58D for aircraft without MMS and OH-58DM for those aircraft with MMS, then press DO.
d. Use cursor keys to highlight Tail Number, and then press DO.
e. Use cursor keys to highlight a tail number or enter a new tail number (up to seven digits), then press DO.
Flight Plan is highlighted. Press DO.
g. Use cursor keys to highlight flight plan INT-SG. Press DO.
h. Enter the Measure mode by pressing F1.
Press DO when the aircraft is stable at the highlighted selection. The first time the DO key is pressed, the system
performs a self-test of all installed equipment and readies the DAU to acquire data for that Test State (the CADU will
prompt the operator with an asterisk and the test condition when all equipment is ready). Verify that the pilot is at
the required Test State (65%_NR or 35%_TQ for OH-58D aircraft with SG. 65% Nr, 65%NrC or 35% TQ for
OH-58DM aircraft) and press DO again. Perform this operation each time a measurement is completed and
another Test State is highlighted. The AVA will acquire track and balance data and return to the selection menu.
After the last measurement is completed, press DO on Finish, then press DO on Diagnostics. If
measurements are within specified limits, press QUIT to Main Menu. Proceed to task 4.
k. If measured values exceed specifications, press DO to execute diagnostics. The AVA will make
recommendations to correct track and balance using pitch change links, trim tabs, and hub balance weights.
Shut down aircraft and perform all corrections displayed on the diagnostic screen. Check to ensure that all
screens of a multiple screen solution have been displayed. Do not use a partial set of adjustments.
It should take approximately three initial runs to get the
rotor in track. If after three runs the rotor track is not
within the 0.1-0.2 inch range, review the adjustment
procedures to make sure the correct adjustments are
being made and re-orient the aircraft so that the
tracker is not looking at the sun or that the sun is at
the left front of the aircraft. As long as the 65% and
100% track are in the 0.1-inch range (2-3 mm) it is
acceptable to discontinue the initial mode and press
into flight if problems are being encountered getting
the 65% balance acceptable.
m. After corrections are installed, repeat procedure 2 until ground track and balance criteria are met.
n. Proceed to task 4.