TM 1-1520-265-23
Change 2 2-5
2.2 SPLIT CONES (PT).
2.2.1 Description (Figure 2-1, Index No. 2). The split cones and lower pressure plate, in
conjunction with the main shaft nut, secure the shaft extension to the main shaft.
2.2.2 Defects. Defects may occur anywhere on the surface of the split cones. No cracks are
allowed.
2.2.3 Primary method. Fluorescent Penetrant.
2.2.3.1 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.
2.2.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance
and the split cones removed in accordance with the applicable technical manuals listed in Table 1-1.
2.2.3.3 Access. Not applicable.
2.2.3.4 Preparation of Part. Refer to Preparation of Part or Area for NDI, paragraph 1.4.4.
2.2.3.5 Inspection Procedure. Perform fluorescent penetrant inspection. Refer to Fluorescent
Penetrant Method, paragraph 1.4.7 and Table 1-5. Inspect area of concern. See Figure 2-2.
2.2.3.6 Making and Recording of Inspection Results. Mark and record inspection results as
required by paragraph 1.3.
2.2.4 Backup Method. None required.
Figure 2-2. Split Cones
