TM 1-1520-265-23
4.11.3.6
Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 4-11
a.
Place probe on a good area in the inspection location and null. Adjust phase as required to obtain horizontal lift-
off.
b.
Inspect the part.
c.
Any signal similar to the notches in the test block are cause for rejection.
NOTE
Either probe identified in paragraph 4.11.3.1 may be used depending primarily on the ease of
accessibility and user friendliness. If the probes are changed, steps 4.11.3.5 b. (1), (2), and (3)
shall be repeated each time a change is made.
4.11.3.7
Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph
1.3.
4.11.4
Backup Method. None required.
4.11.5
System Securing. The gunner's window, if removed, requires installation in accordance with the applicable
technical manuals listed in Table 1-1.
4.12
GUNNER'S WINDOW UPPER TRACK (ET).
4.12.1
Description (Figure 4-1. Index No. 12). The gunner's window slides forward and aft and is held in place and
guided by an upper track. Tracks are on both sides of the helicopter.
4.12.2
Defects. This inspection is used to verify crack indications found visually on the upper track. No cracks are
allowed.
4.12.3
Primary Method. Eddy Current.
4.12.3.1
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, 900 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
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