TM 1-1520-253-23
CABIN EQUIPMENT SUPPORT STRUCTURE (ET).
4.6.1 Description (Figure 4-1, Index No. 6). This inspection is applicable to the driveshaft supports, cargo hook
supports, litter strap supports, combining transmission longitudinal support beams, and the ramp actuator support
structure contained within the cabin equipment support structure.
4.6.2 Defects. Defects may occur anywhere on the surface of the part. The primary purpose of this inspection is to
verify crack indications found visually. No cracks are allowed.
4.6.3
Primary Method. Eddy Current.
NDI Equipment and Materials. (Refer to Appendix B.)
a. Eddy Current Inspection Unit
b. Probe, straight, shielded surface, 100 KHz-500 KHz
c.
Probe, right angle, shielded surface, 100 KHz-500 KHz, 901/2 inch drop
d. Cable Assembly
e. Reference Block, three-notched aluminum (0.008, 0.020, and 0.040 EDM notches)
f.
Teflon Tape, refer to Table 1-8
g. Aircraft Marking Pencil, refer to Table 1-8
4-13
