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
Inspection Procedure. Refer to Eddy Current Method, paragraph 1.4.11 and Figure 3-22.
The tail rotor 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 22.214.171.124, Sorting Metal Using Eddy Current, to determine
what test block is best suited for this inspection.
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 similarto the notches in the test block is cause for rejection.
Either probe identified in paragraph 126.96.36.199 may be used depending primarily on the
ease of accessibility and user friendliness. If the probes are changed, steps 188.8.131.52 b.
(1), (2), and (3) shall be repeated each time a change is made.
Marking and Recording of Inspection Results. Mark and record the inspection results as required by
3.22.4 Backup Method. Fluorescent Penetrant, refer to paragraph 1.4.7.
3.22.5 System Securing. The tail rotor gearbox, if removed, requires installation in accordance with the applicable
technical manuals listed in Table 1-1.
TAIL ROTOR GEARBOX SHOULDERED SHAFT (MT).
3.23.1 Description (Figure 3-1. Index No. 23). The tail rotor gearbox shouldered shaft is an externally splined shaft
which connects the tail rotor gearbox to the number 6 tail rotor drive shaft.
3.23.2 Defects. This inspection is used to verify crack indications found visually on the tail rotor gearbox shouldered
shaft. No cracks are allowed.
3.23.3 Primary Method. Magnetic Particle.