TM 1-1520-253-23
2.3.3.6 Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 2-3.
a. Place probe on part 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 2.3.3.1 may be used depending primarily on the ease of
accessibility and user friendliness. If the probes are changed, steps 2.3.3.5 b. (1), (2), and (3) shall
be repeated each time a change is made.
2.3.3.7 Marking and Recording of Inspection Results. Mark and record as required by paragraph 1.3.
2.3.4 Backup Method. Fluorescent Penetrant, refer to paragraph 1.4.7.
2.3.5 System Securing. If removed, install the hub oil tank as required in accordance with the applicable technical
manual listed in Table 1-1. Secure the forward and aft transmission work platform.
2.4.1 Description (Figure 2-1, Index No. 4). The pitch varying shaft is the inner component of the pitch varying assembly
of the rotary using head assembly. It is the bearing surface for the horizontal pin and the attach point for the tie bar
assembly.
2.4.2 Defects. Defects may occur anywhere on the surface of the pitch varying shaft. Particular attention shall be given
to the horizontal hinge pin barrel around both sides of shaft from oil tank to droop stop mounting bosses. No cracks are
allowed.
2.4.3 Primary Method. Magnetic Particle.
2.4.3.1 NDI Equipment and Materials. (Refer to Appendix B.)
a. Magnetic Particle Inspection Probe/Yoke
b. Magnetometer
c. Black Light
d. Fluorescent Magnetic Particles
e. Consumable Materials, refer to Table 1-8
f. Aircraft Marking Pencil, refer to Table 1-8
2-6
