TM 1-1520-265-23
4.33.3.4. Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
4.33.3.5. NDI Equipment Settings. Refer to Magnetic Particle Method, paragraph 1.4.8.
4.33.3.6. Inspection Procedure. A magnetic field shall be applied to the part perpendicular to the orientation of possible
cracks. The position required for this inspection is illustrated in Figure 4-33.
a.
Select AC on the AC/DC power switch.
b.
Place probe/yoke on part in position 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.
4.33.3.7. Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph
1.3.
4.33.3.8. 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.
4.33.4. Backup Method. None required.
4.33.5. System Securing. Clean the tail landing gear lock mechanism 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 tail landing
gear lock mechanism, if removed, requires installation in accordance with the applicable technical manuals listed in
Table 1-1.
4.34. TAIL LANDING GEAR WHEEL ASSEMBLY (ET).
4.34.1. Description (Figure 4-1. Index No. 34). The tail landing gear wheel assembly provides a mount for the tires and
permits the helicopter to be rolled during ground handling.
4.34.2. Defects. Defects may occur anywhere on the surface of the tail landing gear wheel assembly. No cracks are
allowed.
4.34.3. Primary Method. Eddy Current.
4.34.3.1. NDI Equipment and Materials. (Refer to Appendix B.)
a.
Eddy Current Inspection Unit
b.
Probe, straight, shielded surface, 100 KHz-500 KHz
c.
Probe, right angle, shielded surface, 100 KHz-500 KHz, 90° 1/2 inch drop
d.
Cable Assembly
e.
Reference Block, three-notched aluminum (0.008, 0.020, 0.040 EDM notches)
f.
Teflon Tape, refer to Table 1-8
g.
Aircraft Marking Pencil, refer to Table 1-8
4-77
