TM 1-1520-264-23
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. (See the standard instrument display shown in Figure 1-7.)
3.11.3.6 Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 3-11.
NOTE
The engine nose gearbox contains a higher conductivity magnesium which will require the use of the
aluminum test block when performing inspections in these areas. Refer to paragraph 1.4.11.4, Sorting
Metal Using Eddy Current, to determine what test block is best suited for this inspection.
a.
Place probe on a good area in the inspection location 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 3.11.3.1 may be used depending primarily on the ease of accessibility
and user friendliness. If the probes are changed, steps 3.1 1.3.5 b. (1), (2), and (3) shall be repeated each
time a change is made.
3.11.3.7 Marking and Recording of Inspection Results. Mark and record the inspection results as required by paragraph
1.3.
3.11.4
Backup Method. Fluorescent Penetrant, refer to paragraph 1.4.7.
3.11.5
System Securing. The engine nose gearbox, if removed, requires installation in accordance with the applicable
technical manuals listed in Table 1-1.
3.12
ENGINE NOSE GEARBOX INPUT QUILL SHAFT (MT).
3.12.1
Description (Figure 3-1. Index No. 12). The engine nose gearbox input quill shaft transmits power from the
engine to the nose gearbox.
3.12.2
Defects. This inspection is used to verify crack indications found visually on the engine nose gearbox input
quill shaft. No cracks are allowed.
3.12.3
Primary Method. Magnetic Particle.
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