TM 1-1520-264-23
3.8.3.5
NDI Equipment Settings. Refer to Magnetic Particle Method, paragraph 1.4.8.
3.8.3.6
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 3-8.
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.
3.8.3.7
Marking and Recording of Inspection Results. Mark and record the inspection results as required by paragraph
1.3.
3.8.3.8
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.
3.8.4
Backup Method. Fluorescent Penetrant, refer to paragraph 1.4.7.
3.8.5
System Securing. Clean the aft hanger bearing flange 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 aft hanger bearing
flange, if removed, requires installation in accordance with the applicable technical manuals listed in Table 1-1.
3.9 AFT HANGER BEARING SUPPORT (ET).
3.9.1
Description (Figure 3-1. Index No. 9). The aft hanger bearing support is semi rigid consisting of a single
support and a sealed bearing assembly. The support incorporates three spherical bearings in the mount holes which
mount the support to the bracket.
3.9.2
Defects. This inspection is used to verify crack indications found visually on the aft hanger bearing support.
No cracks are allowed.
3.9.3
Primary Method. Eddy Current.
3.9.3.1
NDI Equipment and Materials. (Refer to Appendix B.)
a.
Eddy Current lnspection 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, and 0.040 EDM notches)
f.
Teflon Tape, refer to Table 1-8
g.
Aircraft Marking Pencil, refer to Table 1-8
3-18
