TASK 4 - TRACK MAIN ROTOR IN FLIGHT
Ensure tail rotor is balanced (task 5) before proceeding
Main rotor in-flight vertical tracking should be performed when any of the following occurs:
1/REV in-flight vertical vibration is unacceptable.
Changes have been made to the track of one or more main rotor blades as a result of performing ground-tracking
adjustments (task 2 or task 3).
PROCEDURE 1: EQUIPMENT INSTALLATION
Aircraft ground track and balance specified requirements
(tasks 2 or 3) are to be completed prior to performing in-
flight Test States if the aircraft was not in a previously
flight worthy condition. Do not exceed any airspeed at
which excessive vibration is present.
For UH-1 with composite blades it is suggested that the
operator stop working the rotor when the vertical 1/REV
vibrations are in the 0.2 to 0.3 ips range at cruise flight.
Working the rotor levels significantly lower will obtain a
smooth 1/REV vibration but the perceived vibration by
the crew will not be as good due to the feel of 2/REV
vibrations in absence of the 1/REV. vibration.
a. Install test equipment (refer to task 1).
b. Turn on DAU.
c. Turn on CADU.
PROCEDURE 2: PERFORM FLIGHT MEASUREMENTS
a. Press QUIT on the CADU until all selections are undefined.
b. Use cursor keys to highlight Aircraft Type, and then press DO.
c. Use cursor keys to highlight UH1 for metal blades and UH1CRB for composite blades, then press DO.
d. Tail Number is highlighted. 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. Press DO.
h. Enter the Measure mode by pressing F1. Verify that IDLE is highlighted.
Press DO when the aircraft is stable at the highlighted selection. Verify that the aircraft is at the required Test
State (IDLE, FPG100, HOVER, 60K, 90K, 110K, or L/DOWN) 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
vibration data at each Test State and then 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 and proceed to step o.
k. If measured values exceed specifications, press DO to enter the DIAGS mode.
Evaluate the percentage improvements obtainable through View Predictions. The AVA will make
recommendations to correct for excessive vibration. Perform corrections, making certain to view all screens of
a multiple screen solution.