TM 1-1520-264-23
4.22.3.2
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 link shall be removed in accordance with the applicable technical
manuals listed in Table 1-1.
4.22.3.3
Access. Access is through doors (Figure 1-4, Items LN3 or RN3, opened).
4.22.3.4
Preparation of Part. Refer to Preparation of Part or Area for NDI, paragraph 1.4.4.
4.22.3.5
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 4-22.
4.22.3.6
Marking and Recording of Inspection Results. Mark and record the inspection results as required by
paragraph 1.3.
4.22.4
Backup Method. None required.
4.22.5
System Securing. Clean the link to remove inspection media. Refer to Post Cleaning and Restoration of Part
or Area After NDI, paragraph 1.4.16. The door assembly rig connecting link, if removed, requires installation in
accordance with the applicable technical manuals listed in Table 1-1.
4.23 AFT INBOARD ENGINE MOUNT SUPPORT (ET).
4.23.1
Description (Figure 4-1. Index No. 93)
. The aft inboard engine mount supports are made of titanium and
provide support at the aft end of the engines. There are two aft engine mount supports, one on each side of the
helicopter.
4.23.2
Defects. Defects can occur anywhere on the surface of the aft inboard engine mount support. The primary
purpose of this inspection is for: (1) confirmation of crack indications previously identified by visual inspection; (2)
verification that dents, scratches, or gouges do not conceal cracks; and (3) identifying the size of confirmed cracks.
Typically, no cracks are allowed. In some cases, cracks may be allowed up to the size specified in the associated
technical manuals listed in Table 1-1.
4.23.3
Primary Method. Eddy Current.
4.23.3.1
NDI Equipment and Materials. (Refer to Appendix B.)
a.
Eddy Current Inspection Unit
b.
Probe, straight, shielded surface, 100 KHz-500 KHz
c.
Probe, right angle, shielded surface, 100 KHz-500 KHz, 90
°
1/2 inch drop
d.
Cable Assembly
e.
Reference Block, three-notched itanium (0.008, 0.020, and 0.040 EDM notches)
f.
Teflon Tape, refer to Table 1-8
g.
Aircraft Marking Pencil, refer to Table 1-8
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