TM 1-1520-253-23
5.4.1 Description (Figure 5-1 . Index No. 4). The engine mount adapter attaches to the engine allowing an attachment
point for the attaching link from the engine mount cap.
5.4.2 Defects. This inspection can be used at any time but it is primarily used to verify cracks found visually during
excessive G-force load inspections.
5.4.3 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, 90112 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
5.4.3. 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.
5.4.3.3 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.
5.4.3.4 Preparation of Part. The engine mount adapter shall be thoroughly cleaned. Refer to Preparation of Part or
Area for NDI, paragraph 1.4.4.
5.4.3.5
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%
