TM 1-1520-238-23
6-12
Change 9
6.1.
DRIVE SHAFT INSPECTION – continued
(4) Check hanger assembly bearing for smooth rotation. Replace hanger bearing assembly if rotation is not
smooth.
(5) Check for nicks deeper than 0.020 INCH.
(6) Check for grease seal leakage. None allowed.
(7) Check bearings for evidence of overheating (discoloration of bearing area seals or housing paint). None
allowed. Replace bearings (para 6.7 or 6.10).
s. Check all anti-flail and intermediate gearbox diffuser for cracks.
(1) Check visibly or with fluorescent inspection kit. None allowed.
(2) Check for deformation (out of round). None allowed.
(3) Check for nicks deeper than 0.020 INCH. None allowed.
t. Check APU anti-flail for wear on its inside diameter.
(1) Radial wear is acceptable to 0.040 INCH maximum depth measured at any point.
(2) Check for scratches or gouges in aluminum-bronze coating. Can not exceed 20 PERCENT of surface
area.
(3) Check for flaking or peeling of aluminium-bronze coating. None allowed.
u. Check aft hanger support.
(1) Dents and scratches up to 0.032 INCH deep are allowable but must be blended out.
(2) Triple bolt/bearing arrangement must prevent all radial play.
(3) Replace individual loose bushings and bearings to eliminate play.
v. Inspect all mounting flange bolt holes.
(1) Using plug gauges 0.2505 INCH and 0.2517 INCH, inspect all mounting bolt holes for proper size. Replace
units with bolt holes that exceed 0.2517 INCH diameter.
(2) Inspect couplings/shafts for elongated or damaged bolt holes. None allowed.
w. Nutation check.
(1) Remove No. 3 tail rotor shaft (para 6.5) and forward hanger bearing coupling (para 6.6) from forward
hanger bearing.
NOTE
Nutation is the angular movement of a bearing from its center axis. This movement is not rotation.
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