18.104.22.168 Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 2-19.
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 22.214.171.124 may be used depending primarily on the ease of accessibility and user
friendliness. If the probes are changed, steps 126.96.36.199 b. (1), (2), and (3) shall be repeated each time a change is
Marking and Recording of Inspection Results. Mark and record the inspection results as required by
Backup Method. None required.
System Securing. The main rotor hub bearing, if removed, requires installation in accordance with the applicable
technical manuals listed in Table 1-1.
MAIN ROTOR LOWER SHOE (ET).
Description (Figure 2-1. Index No. 20). The main rotor lower shoe is attached at the base of the main rotor hub
and provides a mounting point for the droop stop follower.
Defects. This inspection is used to verify crack indications found visually on the main rotor lower shoe. No cracks
Primary Method. Eddy Current.
188.8.131.52 NDI Equipment and Materials. (Refer to Appendix B.)
Eddy Current Inspection Unit
Probe, straight, shielded surface, 100 KHz-500 KHz
Probe, right angle, shielded surface, 100 KHz-500 KHz, 90 °
1/2 inch drop
Reference Block, three-notched aluminum (0.008, 0.020, and 0.040 EDM notches)
Teflon Tape, refer to Table 1-8
Aircraft Marking Pencil, refer to Table 1-8
Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. A 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 main rotor lower shoe shall be removed in accordance with the
applicable technical manuals listed in Table 1-1.