TM 1-1520-238-23
Change 7
5-12.1/(5-12.2 blank)
5.1.
MAIN ROTOR INSPECTION – continued
CAUTION
Do not manually press suspect areas. This will cause blade to yield to pressure causing core shear.
Crackling sound is evidence of core shear.
(3) Check main rotor blade (15) for bonding separation.
(a) Coin tap suspect area to detect debonding of skin from honeycomb. Tapping alternately between a
suspect area and a bonded area will produce a different sound. A dull sound (thud) will indicate a skin
to honeycomb debonding or core shear. Repair debonding defect (para 5.2),
(4) Check rotor blade (15) for scratches, nicks, and gouges (para 5.2).
(5) Check rotor blade (15) for dents and depressions (para 5.2).
(6) Visually check rotor blade (15) leading edge tip (31) for loose or missing screws. None allowed.
(7) Check rotor blade (15) leading edge (32) for paint erosion (para 5.2).
(8) Check entire upper/lower and trailing edge (33) surfaces of main rotor blade (15) for cracks and voids.
NOTE
Pay particular attention to main rotor blade trailing edge for cracking.
(a) Check main rotor blade (15) for cracks visually and by wiping upper and lower surfaces of blade and
top and bottom of trailing edge (33) with cloth. Snagging of cloth indicates a crack. Use cloth (item 51,
App F).
(b) If cracks are suspected, examine with magnifier. No cracks allowed.
(c) Do not manually press suspect areas. This will cause blade (15) to yield to pressure causing core
shear. Crackling sound is evidence of core shear.
(9) Check rotor blade static discharger (34) for loose attachment and fraying (para 5.15).
u. Inspect main rotor seal housing, bearing retainer, hub nut retainer, and bolt for grease leakage.
(1) Following first few flights and until newly packed bearing has accumulated 25 flight hours, grease leakage
must continue to decrease or stop.
(2) After 25 flight hours no grease leakage is permitted only an occasional light trace.
(3) When wiping grease from the rotor head, care must be exercised to avoid disturbing dried grease
accumulated around the seal. Dried accumulated grease around the seal enhances the seal’s effective-
ness.
v. Secure access doors T250L, T250R, T290L, T290R, and L325 (para 2.2).
END OF TASK
