BHT-412-MM-2
5-00-00
Page 226 Rev. 23 15 DEC 2015
Export Classification C, ECCN EAR99
Pratt & Whitney
Canada Engine
Maintenance Manual
a. Combining gearbox shall be removed and returned to
Pratt & Whitney Canada for investigation.
b. Inspect transmission spiral bevel gear as follows:
BHT-412-CR&O (1) Gain access to left side of transmission and, if
installed, remove rotor brake and quill assembly or rotor brake
quill port cover.
(2) Utilizing rotor brake quill port opening, inspect all
sixty two teeth of main spiral bevel gear convex side for
unsatisfactory conditions such as scoring, hard lines, nicks,
dents, chipping, metal deformation, etc. Inspect all 62 teeth on
spiral bevel gear concave side (Figure 5-7).
Inspection mirrors and a suitable light are required.
The rotor must be turned slowly to permit inspection
of all gear teeth.
BHT-412-CR&O (3) Remove and replace any gear not meeting
inspection requirements set forth in step (2). Overhaul rotor
brake quill.
Components removed from a helicopter for
evaluation following combining gearbox clutch
nonengagement, misengagement, or in-flight
slippage shall be evaluated as an interrelated group.
Removal records accompanying each component
shall cross reference part and serial numbers of
other drive system components removed for
evaluation.
(4) Install rotor brake and quill.
(5) Install cowling and inspection panels.
5-43. AFTER ENGINE COMBINING GEARBOX CLUTCH NON-ENGAGEMENT,
MISENGAGEMENT, OR IN-FLIGHT SLIPPAGE (CONT)
DATA REFERENCE INSPECTION TASK DESCRIPTION
INITIAL
MECH OTHER
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