TM 1-1520-238-23
Change 4
6-291
6.66.
MAIN TRANSMISSION ROTOR BRAKE DISK REMOVAL/INSTALLATION
6.66.1. Description
This task covers:
Removal. Cleaning. Inspection. Installation.
6.66.2. Initial Setup
Tools:
Aircraft maintenance tool kit (item 372, App H)
0.000 - 0.100-inch outside micrometer caliper (item 51,
App H)
Aircraft maintenance fixture (item 133, App H)
0.000 - 0.125-inch dial indicator depth gage (item 145,
App H)
1/2-inch hexagon x 1/2-inch drive screwdriver socket
wrench attachment (item 321, App H)
Rotor brake socket spanner wrench (item 432, App H)
700 - 1600 inch-pound 1/2-inch drive click type torque
wrench (item 433, App H)
Personnel Required:
68D
Aircraft Powertrain Repairer/NDI
67R3F
Attack Helicopter Repairer/Technical
Inspector
Equipment Conditions:
Ref
Condition
1.57
Helicopter safed
1.62
Lock rotor brake (if transmission is installed)
6.114
Right primary lube oil rotary pump removed
(if transmission is removed)
2.2
Access doors T250L, T250R, T290L,
T290R, and L325 opened
WARNING
FLIGHT SAFETY PART
The main transmission is a flight safe-
ty part. Failure to follow maintenance
instructions may result in serious
injury or death of crewmembers
and/or serious damage to the
helicopter.
CAUTION
Do not mix manufacturers’ disks and ac-
tuators in one assembly. Damage to heli-
copter will result if disks and actuators
from different manufacturers are mixed in
one assembly.
NOTE
If main transmission is installed in air-
craft, ensure rotor brake is in LOCKED
position; this will prevent main transmis-
sion rotor brake disk from turning.
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M04-0522-1
