TM 1-1520-264-23
4.14
TRANSMISSION ROTOR SUPPORT STRUT ASSEMBLIES (ET).
4.14.1
Description (Figure 4-1. Index No. 14). There are eight transmission rotor support strut assemblies. They are
attached between rotor mast support base and the fuselage. They are located in the center fuselage area.
4.14.2
Defects. Defects can occur anywhere on the surface of the transmission rotor support strut assemblies. No
cracks are allowed.
4.14.3
Primary Method. Eddy Current.
4.14.3.1
NDI Equipment and Materials. (Refer to Appendix B.)
a.
Eddy Current Inspection Unit
b.
Probe, straight, shielded surface, 100 KHz-500 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
4.14.3.2
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 transmission rotor support strut assemblies shall be
removed in accordance with the applicable technical manuals listed in Table 1-1.
4.14.3.3
Access. Access is from the main transmission access panels (Figure 1-4, Items L200 and R200).
4.14.3.4
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area f
or NDI,
paragraph 1.4.4.
4.14.3.5
NDI Equipment Settings.
a.
Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-19e
”
Frequency F1
- 200 KHz
F2
- off
HdB
- 57.0
VdB
- 69.0
Rot
- 56°°
Probe drive - mid
LPF
- 100
HPF
-0
H Pos
- 80%
VPos
- 20%
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