TM 1-1520-264-23
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 2.7.3.1 may be used depending primarily on the
ease of accessibility and user friendliness. If the probes are changed, steps 2.7.3.5 b.
(1), (2), and (3) shall be repeated each time a change is made.
2.7.3.7 Marking and Recording of Inspection Results. Mark and record the inspection results as
required by paragraph 1.3.
2.7.4
Backup Method. None required.
2.7.5
System Securing. T he main rotor blade weight support fitting, if removed, requires installation in accordance
with the applicable technical manuals listed in Table 1-1.
2.8
MAIN ROTOR MAST (MT).
2.8.1
Description (Figure 2-1. Index No. 8). The main rotor mast provides the attachment point for the main rotor head
assembly.
2.8.2
Defects. This inspection is used to verify crack indications found visually on the main rotor mast. No cracks are
allowed.
2.8.3
Primary Method. Magnetic Particle.
2.8.3.1 NDI Equipment and Materials. (Refer to Appendix B.)
a.
Magnetic Particle Inspection ProbeNYoke
b:
Magnetometer
c.
Black Light
d.
Fluorescent Magnetic Particles, refer to Table 1-8
e.
Consumable Materials, refer to Table 1-8
f.
Aircraft Marking Pencil, refer to Table 1-8
NOTE
Hand-held magnetic coil may be used. Refer to paragraph 1.4.8.1.2 and Figure 1-6.
2.8.3.2 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 applicable positions of this procedure. If required, the main rotor mast shall be removed in
accordance with the applicable technical manuals listed in Table 1-1.
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