TM 1-1520-265-23
Change 2 2-7
a. Select AC on the AC/DC 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.
2.3.3.7 Marking and Recording of Inspection Results. Mark and record inspection results as
required by paragraph 1.3.
2.3.3.8 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.
2.3.4
Backup Method. None required.
2.3.5
System Securing. Clean the bolts or pins 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 bolts or pins require installation in accordance with the applicable technical manuals listed in
Table 1-1.
2.4 NONFERROUS ROTOR SYSTEM BOLTS AND PINS.
2.4.1
Description (Figure 2-1, Index No. 4). This inspection is peculiar to all nonferrous bolts and
pins contained within the rotor system.
2.4.2
Defects. Defects may occur anywhere on the surface of the bolt or pins. No cracks are
allowed.
2.4.3. Primary Method. Fluorescent Penetrant.
2.4.3.1 NDI Equipment and Materials. (Refer to Appendix B.) Inspection equipment is listed in
Table 1-7. AMS 2644 level 3 penetrant materials shall be selected from the approved list in Table
1-8. Parts requiring flourescent penetrant inspection shall be cleaned prior to inspection with
n--Propyl Bromide (vapor degreasing only)(Table 1--8), DS--108 (Table 1--8), Electron (Table 1--8),
Positron (Table 1--8). DS--108, Electron, Positron must be followed by an acetone (Table 1--8) rinse
or wipe: or drying until there is no visible solvent residue left on parts..
2.4.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance and
the bolts or pins removed in accordance with the applicable technical manuals listed in Table 1-1.
2.4.3.3 Access. Not applicable.
2.4.3.4 Preparation of Part. Refer to Preparation of Part or Area for NDI, paragraph 1.4.4.
2.4.3.5Inspection Procedure. Perform fluorescent penetrant inspection. Refer to Fluorescent
Penetrant Method, paragraph 1.4.7 and Table 1-5. Inspect area of concern. See Figure 2-4.
2.4.3.6Marking and Recording of Inspection Results. Mark and record inspection results as
required by paragraph 1.3.
2.4.4
Backup Method. None required.
2.4.5
System Securing. Clean the bolt or pins to remove inspection media. Refer to Post
Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The bolts and pins require
installation in accordance with the applicable technical manual listed in Table 1-1.
