TM 1-1520-264-23
3.4.4
Backup Method. None required.
3.4.5
System Securing. Clean the drivetrain flange thoroughly to remove all residual magnetic particle media.
Refer to Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The drive shaft requires installation
in accordance with the applicable technical manuals listed in Table 1-1.
3.5
DAMPER AND ANTI-FLAIL SUPPORTS (ET).
3.5.1
Description (Figure 3-1. Index No. 5). The damper and anti-flail supports are installed on the drive shafts
between the main transmission and the intermediate gearbox. The damper assemblies define the natural frequencies of
the drive shafts to allow them to operate at critical speeds and the anti-flail assemblies hold the drive shafts in position if
partial or full separation of the drive shaft occurs.
3.5.2
Defects. This inspection is used to verify crack indications found visually on the damper and anti-flail
supports. No cracks are allowed.
3.5.3
Primary Method. Eddy Current.
3.5.3.1
NDI Equipment and Materials. (Refer to Appendix B.)
a.
Eddy Current Inspection Unit
b.
Probe, straight, shielded surface, 100 KHz-500 KHz
c.
Probe, right angle, shielded surface, 100 KHz-500 KHz, 90 °
1/2 inch drop
d.
Cable Assembly
e.
Reference Block, three-notched aluminum (0.008, 0.020, and 0.040 EDM notches)
f.
Teflon Tape, refer to Table 1-8
g.
Aircraft Marking Pencil, refer to Table 1-8
3.5.3.2
Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. A partial inspection
for cause (visual indications, sites of mechanical damage, corrosion, etc.) may be performed on all exposed surfaces of
the installed part using this procedure. If required, the damper and anti-flail supports shall be removed in accordance
with the applicable technical manuals listed in Table 1-1.
3.5.3.3
Access. Accessibility of the damper and anti-flail supports varies considerably. Refer to Figure 1-4 and Table
1-2 to locate applicable access provisions.
3.5.3.4
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
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