TM 1-1520-265-23
Probe drive
- mid
LPF
- 100
HPF
-0
H Pos
- 80%
V Pos
- 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.)
4.15.3.6
Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.
11 and Figure 4-15.
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 are cause for rejection.
NOTE
Either probe identified in paragraph 4.15.3.1 may be used depending primarily on the ease of
accessibility and user friendliness. If the probes are changed, steps 4.15.3.5 b. (1), (2), and (3)
shall be repeated each time a change is made.
4.15.3.7
Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph
1.3.
4.15.4
Backup Method. None required.
4.15.5
System Securing. The tail pylon requires securing in accordance with the applicable technical manuals listed
in Table 1-1.
4.16
TAIL ROTOR PYLON SKIN, STATION 200 (ET).
4.16.1
Description (Figure 4-1. Index No.16). This procedure is applicable to tail rotor pylon skin at station 200. If
skin cracks are noted, inspect inside surfaces of fitting where attached to front spar cap angles.
4.16.2
Defects. This inspection is used to verify crack indications found visually on the tail rotor pyIon. No cracks are
allowed.
4.16.3
Primary Method. Eddy Current.
4-37
