TM 1-1520-265-23
a.
Select AC on the AC/DC power switch.
b.
Place probe/yoke on part in position 1 as shown.
c.
Press the test switch and apply a light coat of magnetic particle media at the same time. Remove the media
momentarily before removing the current. Current should be applied for no more than five seconds.
d.
Inspect for cracks using the black light.
e.
Demagnetize before moving to the next position. Refer to paragraph 6.19.3.8.
f.
Repeat steps a. through e. for positions 2 through 5.
6.19.3.7 Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph 1.3.
6.19.3.8 Demagnetization. With the switch remaining in the AC position, place the probe/yoke legs in the same position
used for magnetizing. Press the test switch and withdraw the probe/yoke from the part for a distance of two feet before
releasing the switch.
6.19.4 Backup Method. None required.
6.19.5 System Securing. Clean the forward bellcrank thoroughly to remove all residual magnetic particle media. Refer
to Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The forward bellcrank, if removed,
requires installation in accordance with the applicable technical manuals listed in Table 1-1.
6.20 LATERAL BELLCRANK (MT).
6.20.1 Description (Figure 6-1. Index No. 20). The lateral bellcrank, supported by the bellcrank support (bridge) in
the swashplate linkage installation, transfers flight control movements through a connecting servo link to the main rotor
swashplate. It is machined from a 4340 steel forging, cadmium plated, and protected by epoxy primer and polyurethane
paint.
6.20.2 Defects. This inspection is used to verify crack indications found visually on the lateral bellcrank. Inspect all
reworked areas for cracks. Inspect lateral bellcrank lug and rib surfaces. Visually inspect bellcrank flanged pivot
bushings. No cracks are allowed.
6.20.3 Primary Method. Magnetic Particle.
6.20.3.1 NDI Equipment and Materials. (Refer to Appendix B.)
a.
Magnetic Particle Inspection Probe/Yoke
b.
Magnetometer
c.
Black Light
d.
Fluorescent Magnetic Particles, 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.
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