TM 1-1520-264-23
3.24.3.6
Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 3-24.
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 3.24.3.1 may be used depending primarily on the
ease of accessibility and user friendliness. If the probes are changed, steps 3.24.3.5 b.
(1), (2), and (3) shall be repeated each time a change is made.
3.24.3.7
Marking and Recording of Inspection Results. Mark and record the inspection results as required by
paragraph 1.3.
3.24.4
Backup Method. Fluorescent Penetrant, refer to paragraph 1.4.7.
3.24.5
System Securing. The tail rotor gearbox retainers, if removed, require installation in accordance with the
applicable technical manuals listed in Table 1-1.
3.25
TAIL ROTOR GEARBOX FORWARD AND AFT STRUT (MT).
3.25.1
Description (Figure 3-1. Index No. 25). The tail rotor gearbox forward and aft struts are connected to the tail rotor
gearbox and the vertical stabilizer to provide structural support for the tail rotor gearbox assembly.
3.25.2
Defects. This inspection is used to verify crack indications found visually on the tail rotor gearbox forward and
aft strut. No cracks are allowed.
3.25.3
Primary Method. Magnetic Particle.
3.25.3.1
NDI Equipment and Materials. (Refer to Appendix B.)
a.
Magnetic Particle Inspection Probe/Ydke
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.
3-56
