TM 1-1520-265-23
3-14
Change 3
Figure 3-6. Tail Rotor Drive Shaft Coupling
3.6.3.6 Marking and Recording of Inspection Results. Mark and record inspection results as
required by paragraph 1.3.
3.6.4 Backup Method. None required.
3.6.5 System Securing. Clean the tail rotor drive shaft coupling to remove inspection media.
Refer to Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The tail rotor
drive shaft coupling, if removed, requires installation in accordance with the applicable technical
manuals listed in Table 1-1.
3.7 OIL COOLER DRIVE SHAFT (ET).
3.7.1 Description (Figure 3-1, Index No. 7). The oil cooler drive shaft is aft of, and driven by, the
shouldered shaft of the fan. The fan forces air through the radiator, which cools the hot oil from the
main module sump. The forward flange of the oil cooler drive shaft is steel, the aft end is titanium,
and the drive shaft tube is aluminum.
3.7.2 Defects. This inspection is used to verify crack indications found visually on the aluminum
and titanium portions of the oil cooler drive shaft. No cracks are allowed.
3.7.3 Primary Method. Eddy Current.
3.7.3.1 NDI Equipment and Materials. (Refer to Appendix B.)
a. Eddy Current Inspection Unit
b. Probe, straight, shielded surface, 2 MHz (Titanium)
c. Probe, right angle, shielded surface, 100 KHz-500 KHz, 90_ 1/2 inch drop (Titanium)
d. Probe Adapter
e. Cable Assembly
f. Reference Block, three-notched aluminum (0.008, 0.020, 0.040 EDM notches)
g. Reference Block, three-notched titanium (0.008, 0.020, 0.040 EDM notches)
h. Teflon Tape, refer to Table 1-8
i. Aircraft Marking Pencil, refer to Table 1-8
