TM 1-1520-25323
4.9.3.2
Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance and the rescue
hatch lower door gearbox removed and disassembled in accordance with the applicable technical manuals listed in Table
4.9.3.3
Access. Not applicable.
4.9.3.4
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
4.9.3.5
NDI Equipment Settings. Refer to Magnetic Particle Method, paragraph 1.4.8.
4.9.3.6
Inspection Procedure. A magnetic field shall be applied to the part perpendicular to the orientation of
possible cracks. Position(s) required for this inspection are illustrated in Figure 4-9.
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.
4.9.3.7
Marking and Recording of Inspection Results.
Mark and record the inspection results as required by
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