18-14 Balance Adjustment
WARNING
A rotor which is smooth after balancing but goes out of balance
within a few flights is suspect and must be examined by RHC
before further flight.
A. Tip Weights (Spanwise Balance Adjustment)
1. Remove screws securing tip cover to blade. Balance rotor assembly spanwise
by adjusting tip weights as required per Figure 18-2. Washers may be trimmed.
Refer to Figure 18-4A. Apply light coat A257-9 anti-seize to threads and install
screws securing tip weights to blade; special torque screws to 40 in.-lb. Apply
light coat A257-9 anti-seize to threads and install screws securing tip cover to
blade; special torque screws to 40 in.-lb.
(1) AN960-10 or NAS1149F0363P Washer = (2) AN960-10L or NAS1149F0332P Washers
(1) C298-2 Weight = (5) AN960-10 or NAS1149F0363P Washers
(1) C298-3 Weight = (11) AN960-10 or NAS1149F0363P Washers
(1) C298-4 Weight = (4) C298-3 Weights
B. Teeter Hinge Bolt Shims (Chordwise Balance Adjustment - Coarse Adjustment)
1. Remove and discard teeter hinge nut cotter pin. Remove nut, thrust washer, and
any shims.
2. Have two people cone the main rotor blades. Push out teeter hinge bolt (and any
shims) with another bolt.
3. Balance rotor assembly chordwise by moving (or exchanging) existing teeter
hinge shims to other side of bolt (under head or under nut) as required per Figure
18-2. Install teeter hinge bolt per § 62-10.
C. Chord Arm Weight (Chordwise Balance Adjustment - Fine Adjustment)
1. Balance rotor assembly chordwise by adjusting chord arm weights or washers per
Figure 18-2. Total weight not to exceed four A255-2 weights (or equivalent).
(1) A255-1 Weight = (8) AN970-4 Washers
(1) A255-2 Weight = (3) A255-1 Weights
APR 2017 Chapter 18 Track and Balance Page 18.10A
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