TM 1-1520-253-23
2.14.3 Primary Method. Bond Testing.
NDI Equipment and Materials. (Refer to Appendix B.)
a.
Bond Test Unit
b.
Probe, Mechanical Impedance Analysis
c.
Probe Holder
d.
Cable Assembly
e.
Test block, metal honeycomb with skin thickness closest to that of the panel to be inspected.
f.
Test Block, Composite Defect Standard #1
g.
Teflon Tape, refer to Table 1-8
h.
Aircraft Marking Pencil, refer to Table 1-8
2.14.3.2 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 weather protective cover shall be removed in accordance with
applicable technical manuals listed in Table 1 -1.
2.14.3.3 Access. Access is from the forward and aft transmission work platforms. See Figure 1-4 - CH-47: 9, 27, and/or
34; MH-47: 16 and 17.
2.14.3.4 Preparation of Part. The components shall be thoroughly cleaned. Refer to Preparation of Part or Area for
NDI, paragraph 1.4.4.
2.14.3.5 NDI Equipment Settings. Refer to Bond Test Equipment, paragraph 1.4.6.1.
a. Attach cable and probe to Bondmaster. Protect probe with Teflon tape and install in probe holder.
b. Turn on Bondmaster, press SPCL, and make the following adjustments:
H Pos
-40%
V Pos
- 80%
PHASE REF
-0
DRIVE
- MID
c. Press SET and select DISPLAY - PHASE.
d. Place probe on the good area of test block #1 and press GOOD PART. Do this several times while moving the
probe to different spots in the good area of the test block. Note the video signature for each. Select and enter a
representative good area by pressing GOOD PART one last time.
e. Place probe on void area of test block #1 and press BAD PART. Do this several times while moving the probe
slightly to different positions within the void area. Select and enter a position that gives a strong difference
between good and void areas. (See Figure 1-5.) Use DIFF soft key to observe difference between good and
bad areas of test block.
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