TM 1-1520-238-23
Change 4
1-381
1.137.
SPECIAL INSPECTION CHECKLIST – continued
Helicopter Serial No.:
Date:
Area
No.
REQUIREMENT
EVERY
Item
Status
Special
Inspection
No.
2,4,6,7
17
(cont)
Below 115% dual-engine overtorque - No inspection required.
(cont)
115% to 130% dual-engine overtorque:
NOTE
Refer to special inspection 14 if dual-engine overtorque is accompanied
by rotor overspeed.
a. Remove both main transmission input drive shafts and couplings. Check
both shafts, couplings, and all drive bolt holes for cracks, enlargement,
deformation, and other indications of overstress.
b. Check both engine nose gearboxes and main transmission for cracks or
oil leakage.
c. Remove both engine nose gearbox oil filters and main transmission oil
filters. Internally check each filter for metallic particles (chips). If chips are
evident, perform the following steps:
(1) Take hot oil samples from engine nose gearboxes and main
transmission.
(2) Flush engine nose gearbox.
(3) Flush main transmission (para 1.32).
(4) Ground run aircraft for a minimum of 15 minutes.
(5) Inspect engine nose gearbox and main transmission filters.
(6) If no chips are found, resample after approximately 5 flight hours.
d. Check main rotor drive shaft and drive plate for cracks, distortion, and
other indications of overstress.
e. Check tail rotor drive shaft for cracks, deformation, and other indications of
overstress.
f. Check main rotor strap packs for buckling and other indications of
overstress.
g. Check main rotor blades for buckling at trailing edges.
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