TM 1-1520-253-23
5.8.1 Description (Figure 5-1. Index No. 8). The aft engine mount adapter attaches to the engine. The engine mount link
attaches to the adapter and engine mount structure assemblies.
5.8.2 Defects. This inspection is to verify cracks found visually. No cracks are allowed.
5.8.3 Primary Method. Eddy Current.
a. Eddy Current Inspection Unit
b. Probe, straight, shielded surface, 100 KHz-500 KHz
c. Probe, right angle, shielded surface, 100 KHz-500 KHz, 901/2 inch drop
d. Cable Assembly
e. Reference Block, three-notched aluminum (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
5.8.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. 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 adapter shall be removed in accordance with the applicable technical
manuals listed in Table 1-1.
5.8.3.3 Access. Access is through the engine upper and lower doors from the engine work platform.
See Figure 1-4 CH-47: 20, 21, and 22; MH-47: 18, 20, and 21.
5.8.3.4 Preparation of Part. The adapter shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
5.8.3.5 NDI Equipment Settings.
II
a.
Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-19e .
Frequency F1
- 200 KHz
F2
- off
HdB
- 57.0
VdB
- 69.0
Rot
- 56
Probe drive
- mid
LPF
- 100
HPF
-0
H Pos
- 80%
V Pos
-20%
