TM 1-1520-264-23
3.21
INTERMEDIATE GEARBOX FLANGE AND SHOULDERED SHAFT (MT).
3.21.1 Description (Figure 3-1. Index No. 21). The intermediate gearbox flange and shouldered shaft is an externally
splined shaft which is connected to the intermediate gearbox and the number 6 tail rotor drive shaft.
3.21.2 Defects. T his inspection is used to verify crack indications found visually on the intermediate gearbox flange and
shouldered shaft. No cracks are allowed.
3.21.3 Primary Method. Magnetic Particle.
3.21.3.1
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.
3.21.3.2
Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance and the
intermediate gearbox flange and shouldered shaft removed in accordance with the applicable technical manuals listed in
Table 1-1.
3.21.3.3
Access. Not applicable.
3.21.3.4
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
3.21.3.5 NDI Equipment Settings. Refer to Magnetic Particle Method, paragraph 1.4.8.
3.21.3.6 Inspection Procedure. A magnetic field shall be applied to the part perpendicular to the
orientation of possible cracks. Positions required for this inspection are illustrated in Figure 3-21.
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 3.21.3.8.
f.
Repeat steps a. through e. for positions 2 through 5.
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