TM 1-1520-264-23
4.18.5
System Securing. The TADS/PNVS support fitting requires installation in accordance with the applicable
technical manuals listed in Table 1-1.
4.19 VERTICAL STABILIZER LUGS (ET).
4.19.1
Description (Figure 4-1. Index No. 19)
. The four vertical stabilizer lugs attach the vertical stabilizer to the
tailboom.
4.19.2
Defects. Defects can occur anywhere on the surface of the vertical stabilizer lugs. No cracks are allowed.
4.19.3
Primary Method. Eddy Current.
4.19.3.1
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
4.19.3.2
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 vertical stabilizer lugs shall be removed in accordance with the
applicable technical manuals listed in Table 1-1.
4.19.3.3
Access. Access is through thevertical stabilizer and vertical stabilizer leading edge fairings (Figure 1-4,
Items UR 510 and L/R 530).
4.19.3.4
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
4.19.3.5
NDI Equipment Settings.
a.
Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-1 9e"
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%
4-46
