TM 1-1520-264-23
4.8.3.6 Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 4-8.
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 is cause for rejection.
NOTE
Either probe identified in paragraph 4.8.3.1 may be used depending primarily on the ease of accessibility and user
friendliness. If the probes are changed, steps 4.8.3.5 b. (1), (2), and (3) shall be repeated each time a change is
made.
4.8.3.7
Marking and Recording of Inspection Results. Mark and record the inspection results as required by paragraph
1.3.
4.8.4
Backup Method. None required.
4.8.5
System Securing. The wings, ammunition storage magazine, and barrel nuts require installation in accordance
with the applicable technical manuals listed in Table 1-1.
4.9 GUN AND AMMO SUPPORT MOUNT PADS (ET).
4.9.1
Description (Figure 4-1. Index No. 9). There are four gun and ammo support mount pads, two
located in the forward fuselage area, where they support the forward fuselage gun, and two in the aft fuselage, where
they function as the ammo support aft mount pads.
4.9.2
Defects. Defects can occur anywhere in, or on the surface of, the bushing bore areas.
4.9.3
Primary Method. Eddy Current.
4.9.3.1 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
4.9.3.2 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 gun and ammo support mount pads shall be removed in accordance
with the applicable technical manuals listed in Table 1-1.
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