TM 1-1520-265-23
4.17.5 System Securing. Clean the inspected part to remove inspection media. Refer to Post Cleaning and Restoration
of Part or Area After NDI, paragraph 1.4.16. The tail pylon requires installation in accordance with the applicable
technical manuals listed in Table 1-1.
4.18 TAIL PYLON LOWER STEP (ET).
4.18.1. Description (Figure 4-1. Index No. 18). The step mounted in the tail pylon and is the first step in accessing the
upper pylon/tail rotor area.
4.18.2. Defects. This inspection is used to verify crack indications found visually on the lower step and tube. No cracks
are allowed.
4.18.3. Primary Method. Eddy Current.
4.18.3.1. 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, 0.040 EDM notches)
f.
Teflon Tape, refer to Table 1-8
g.
Aircraft Marking Pencil, refer to Table 1-8
4.18.3.2. 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 lower step shall be removed in accordance with the applicable
technical manuals listed in Table 1-1.
4.18.3.3. Access. Not applicable.
4.18.3.4. Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
4.18.3.5. NDI Equipment Settings.
a.
Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-19eII.
Frequency F1
- 200 KHz
F2
- off
HdB
- 57.0
VdB
- 69.0
Rot
- 56°
Probe drive
- mid
LPF
- 100
HPF
- 0
H Pos
-80%
V Pos
- 20%
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