4.5 FITTINGS, CASTINGS, AND FORGINGS (ET).
Description (Figure 4-1. Index No. 5).
Fittings, castings, and forgings made of nonferrous material can be found
throughout the helicopter. Those items generally serve as structural attaching points, stiffening points, and equipment
Defects. Cracks may occur anywhere on the surface of these components. The primary purpose of this
inspection is for: (1) confirmation of crack indications identified by visual inspections; (2) verification that dents,
scratches, or gouges do not conceal cracks; and (3) ensuring that no cracks remain after any blending is completed
(when allowed). No cracks are allowed.
Primary Method. Eddy Current.
220.127.116.11 NDI Equipment and Materials. (Refer to Appendix B.)
Eddy Current Inspection Unit
Probe, straight, shielded surface, 100 KHz-500 KHz
Probe, right angle, shielded surface, 100 KHz-500 KHz, 90
1/2 inch drop
Reference Block, three-notched aluminum (0.008, 0.020, and 0.040 EDM notches)
Teflon Tape, refer to Table 1-8
Aircraft Marking Pencil, refer to Table 1-8
18.104.22.168 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. A partial inspection for
cause (visual indications, sites of mechanical damage, corrosion, etc.) may be performed on all exposed surfaces of the
installed part using this procedure. If required, the fittings, castings, and forgings shall be removed in accordance with the
applicable technical manuals listed in Table 1-1.
22.214.171.124 Access. Accessibility of fittings, castings, and forgings varies considerably. Refer to Figure 1-4 and Table 1-2 to
locate applicable access provisions.
126.96.36.199 Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
188.8.131.52 NDI Equipment Settings.
Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-1 9e
- 200 KHz