TM 1-1520-253-23
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. (Refer to standard instrument display shown in Figure 1-7.)
5.4.3.6 Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 5-4.
a. Place probe on part in the inspection locations and null. Adjust phase as required to obtain horizontal lift-off.
b. Inspect the part.
c. Any signal similar to the notches in the test block is cause for rejection.
NOTE
Either probe identified in paragraph 5.4.3.1 may be used depending primarily on
the ease of accessibility and user friendliness. If the probes are changed, steps 5.
4. 3. 5 b. (1), (2), and (3) shall be repeated each time a change is made.
5.4.3.7 Marking and Recording of Inspection Results. Mark and record as required by paragraph 1.3.
5.4.4
Backup Method. None required.
5.4.5 System Securing. The engine mount adapter, if removed, requires installation in accordance with applicable
technical manuals listed in Table 1-1. Secure the engine upper and lower doors.
5-9
