TM 1-1520-238-23
Change 4
6-501
SECTION IV. INTERMEDIATE GEARBOX MAINTENANCE
6.121.
INTERMEDIATE GEARBOX INSPECTION
6.121.1. Description
This task covers:
Inspection.
6.121.2. Initial Setup
Tools:
0.20 - 1.00-inch inside micrometer caliper (item 50,
App H)
0.000 - 6.000-inch outside micrometer caliper set
(item 52, App H)
Fluorescent inspection kit (item 138, App H)
0.000 - 0.125-inch dial indicator depth gage (item 145,
App H)
0.001 - 0.200-inch dial indicator (item 176, App H)
References:
TM 55-1500-335-23
Personnel Required:
68D
Aircraft Powertrain Repairer/NDI
67R3F
Attack Helicopter Repairer/Technical
Inspector
WARNING
FLIGHT SAFETY PART
The intermediate gearbox is a flight safety part. Failure to follow maintenance instructions may
result in serious injury or death of crewmembers and/or serious damage to the helicopter.
6.121.3. Inspection
a. Check components for damage and loose mounting. None allowed.
b. Check for loose, missing, or damaged mounting hardware. None allowed.
c. Check grease leakage from gearbox housing and input or output retainers.
(1) Replace seal (para 6.125 or 6.124) if leakage rate exceeds 6 oz per flight.
d. Check gearbox for serviceability.
(1) Check for fractures and/or cracks. None allowed. Use fluorescent inspection kit (TM 55-1500-335-23).
(2) Check mounting feet for damage or corrosion on both sides of mounting area, not deeper than 0.020 INCH
before blending, and not over 25 percent of area. Use depth gage.
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