TM 1-1520-264-23
e.
Reference Block, three-notchedmagnesium (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
3.24.3.2
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 tail rotor gearbox retainers shall be removed in
accordance with the applicable technical manuals listed in Table 1-1.
3.24.3.3
Access. Access is through the tail rotor transmission fairing (Figure 1-4, Item L540).
Maintenance Platforms/Workstands
Use only appropriate platforms, workstands, or other approved locally procured stands
and restraint equipment when working above 10 feet on helicopter in a nontactical
environment. Otherwise, personnel injury could result from accidental falls.
3.24.3.4
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
3.24.3.5
NDI Equipment Settings.
a.
Make the following initial settings on the EddyCurrent Inspection Unit, NORTEC-1 9e1.
Frequency F1
- 200 KHz
F2
- off
HdB
- 57.0
VdB
- 69.0
Rot
- 56°
Probe drive
- mid
LPF
- 100
HPF
-0
H Pos
- 80%
VPos
- 20%
b.
Refer to Eddy Current Method, paragraph 1.4.11. Set up on test block as follows:
(1) Null probe on test block.
(2) Adjust phase as required to obtain horizontal lift-off.
(3) Move probe over all three notches in test block. Adjust gain to obtain a three block vertical signal when probe is
passed over 0.040-inch notch in test block. (See the standard instrument display shown in Figure 1-7.)
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