TM 1-1520-238-23
Change 8
5-232.1
5.51.
TAIL ROTOR ASSEMBLY INSPECTION – continued
NOTE
When sanding topcoat and primer, use 180 cloth (item 47A, App F) to 240 cloth (item 47A, App F) grit
sandpaper. When sanding the filler material, use 240 cloth (item 47A, App F) to 320 grit cloth (item 48,
App F).
NOTE
While sanding the filler material, focus on sanding the filler material only. Incidental sanding of spar and
doubler edges should be kept to a minimum.
NOTE
Do not sand scrim cloth. Scrim cloth is located underneath the filler material. The surface of the scrim
cloth may give visual indications of crazing.
(b) Carefully hand sand the crazing/crack indication with the applicable sandpaper until crazing/crack
disappears or the scrim cloth beneath the filler material becomes visible. Sanding should stop immedi-
ately if bare metal of root fitting becomes visible.
(c) Solvent wipe the indicated area with isopropyl alcohol (item 25A, App F) or acetone (item 1A, App F)
and allow to dry for 15 minutes.
(d) Conduct visual inspection of sanded area for crazing or crack indication using a 10X magnifier and
flashlight or other light source.
1 If crazing or crack indication is no longer visible, proceed to paragraph b.2.
2 If crazing or crack indication is still visible, repeat procedures in paragraph a.6.(b) and a.6.(c)
before proceeding to next paragraph.
(e) If any crack indication remains visible after scrim cloth or bare metal on the root fitting becomes visible,
a debond is presumed.
1 Replace tail rotor blade per paragraph 5.53.
(f) Use a 10X magnifier to inspect the inboard and outboard tail rotor blade surfaces for chordwise
cracking and/or any indication of surface damage between blade stations 25.0 (measured 30 inches
inboard of the blade tip) and 35.0 (measured 20 inches inboard of the blade tip).
1 Use approved limits in table 5.55 for scratches, nicks, gouges and corrosion.
2 Use table 5.56 for dents and depressions.
a If crack is found replace tail rotor blade per paragraph 5.53.
(g) If no cracks are found, proceed to paragraph b.2.
END OF TASK
