Refer to Eddy Current Method, paragraph 1.4.11. Set up on test block as follows: .
(1) Null probe on the appropriate test block - aluminum test block for aluminum alloys, the magnesium test block
for magnesium alloys, or the titanium test block for titanium and non-ferromagnetic stainless steel.
(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.)
188.8.131.52 Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 4-2.
Place probe on a good area in the inspection location and null. Adjust phase as required to obtain horizontal lift-
Inspect the part.
Any signal similar to the notches in the test block is cause for rejection.
Either probe identified in paragraph 184.108.40.206 may be used depending primarily on the
ease of accessibility and user friendliness. If the probes are changed, steps 220.127.116.11 b.
(1), (2), and (3) shall be repeated each time a change is made.
18.104.22.168 Marking and Recording of Inspection Results. Mark and record the inspection results as required by paragraph
Backup Method. None required.
System Securing. The access doors, covers, panels, and fairings, if removed or opened, require installation or
securing in accordance with the applicable technical manuals listed in Table 1-1.
HONEYCOMB CORE FUSELAGE PANELS, VERTICAL FIN, ETC. (BT).
Description (Figure 4-1. Index No. 3). This inspection is applicable to parts or components made of
metallic/nonmetallic skins bonded to metallic/ nonmetallic cores and laminations of facings of metal or fiberglass panels.
The structural assembly components identified for inspection are: forward fuselage honeycomb panels, decking
honeycomb panels, and vertical fin honeycomb panels.
Defects. Perform the NDI method contained herein on the components listed above for the purpose of
verification of void damage identified by visual inspection. Void damage may occur anywhere on either side of bonded
panels as a result of mechanical damage (dents, punctures, scratches, etc.) or fluid intrusion/corrosion.
A void is defined as an unbonded area that is suppose to be bonded. Many subdefinitions are given
such as bond separation, delimitation, lack of adhesive, gas pocket, misfit, etc. This procedure makes
no distinction among these instead grouping under the general term "void."