Textron Bell 412, Maintenance Manual

Page: 266 / 288

BHT-412-MM-2
5-00-00
Page 216
Rev. 26 01 JUN 2018 Export Classification C, ECCN EAR99
(1) Remove tail rotor driveshafts and inspect for the
following conditions. Replace any tail rotor driveshafts
exceeding limits specified in Chapter 65. If one or more of
conditions listed in step a through step d are noted, all hanger
assemblies shall be sent for overhaul evaluation. Note on
removal tag that reason for removal was compressor stall or
surge.
(a) Curvic faces distorted (412 and 412SP only).
(b) Tube bent, twisted, or out of roundness.
(c) Cracks.
(d) Loose or sheared rivets.
(2) Disc pack couplings (412HP and
412EP/412EPI/412EPX only) - Any deformation of disc pack
that results in gaps between laminates that are greater than
0.015 inch (0.381 mm) will require replacement. Not applicable
to 412 and 412SP.
(3) Disc pack coupling bolts - Distortion or cracks in
any bolt will require replacement. Not applicable to 412 and
412SP.
(4) Tail rotor drive adapters - Distortion beyond the
limits specified in Chapter 65 will require replacement.
(5) Tail rotor hub and blade assembly - perform an
overhaul evaluation. Make an entry in component record
showing reason for removal was compressor stall.
(6) Remove main rotor blades retention bolts. Check
412-010-124 type bolts for deformation and perform magnetic
particle inspection on bolts. Inspect 412-010-137-103
expandable bolts for damage. If satisfactory, return to service.
(7) Remove main rotor damper bridge assemblies
and check for deformation of bushings and bushing holes.
(8) Perform close visual inspection of all other main
rotor components.
CONDITIONAL INSPECTIONS
5-41. AFTER COMPRESSOR STALL OR SURGE (CONT)
DATA REFERENCE INSPECTION TASK DESCRIPTION
INITIAL
MECH OTHER