Select AC on the AC/DC power. switch.
Place probe/yoke on part in position 1 as shown.
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.
Inspect for cracks using the black light.
18.104.22.168 Marking and Recording of Inspection Results. Mark and record the inspection results as required by paragraph
22.214.171.124 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.
Backup Method. None required.
System Securing. Clean the main rotor mast retaining ring 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 main rotor mast
retaining ring, requires installation in accordance with the applicable technical manuals listed in Table 1-1.
MAIN ROTOR HUB RETENTION NUT (MT).
Description (Figure 2-1. Index No. 10). The main rotor hub retention nut secures the main rotor hub assembly to
the main rotor mast.
Defects. Defects can occur anywhere on the surface of the main rotor hub retention nut. No cracks are allowed.
Primary Method. Magnetic Particle.
NDI Equipment and Materials. (Refer to Appendix B.)
Magnetic Particle Inspection Probe/Yoke
Fluorescent Magnetic Particles, refer to Table 1-8
Consumable Materials, refer to Table 1-8
Aircraft Marking Pencil, refer to Table 1-8
Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance and the main rotor
hub retention nut shall be removed in accordance with the applicable technical manuals listed in Table 1-1.
Access. Not applicable.