TM 1-1520-265-23a.Select AC on the AC/DC power switch.b.Place probe/yoke on part in position 1 as shown.c.Press the test switch and apply a light coat of magnetic particle media at the same time. Remove the mediamomentarily before removing the current. Current should be applied for no more than five seconds.d.Inspect for cracks using the black light.6.8.3.7Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph 1.3.6.8.3.8 Demagnetization. With the switch remaining in the AC position, place the probe/yoke legs in the same positionused for magnetizing. Press the test switch and withdraw the probe/yoke from the part for a distance of two feet beforereleasing the switch.6.8.4 BackupMethod. None required.6.8.5 SystemSecuring.Clean the collective boost and yaw boost servo thoroughly to remove all residual magneticparticle media. Refer to Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The collective boostand yaw boost servo, if removed, requires installation in accordance with the applicable technical manuals listed in Table1-1.6.9 YAW/PITCH COUPLING LINK (ET).6.9.1 Description(Figure6-1.IndexNo.9) .The yaw/pitch coupling link is a component of the mixer assembly whichis part of the collective control system.6.9.2 Defects.This inspection is used to verify crack indications found visually on the yaw/pitch coupling link. Nocracks are allowed.6.9.3 PrimaryMethod.Eddy Current.6.9.3.1NDI Equipment and Materials. (Refer to Appendix B.)a.Eddy Current Inspection Unitb.Probe, straight, shielded surface, 100 KHz-500 KHzc.Probe, right angle, shielded surface, 100 KHz-500 KHz, 90° 1/2 inch dropd.Cable Assemblye.Reference Block, three-notched aluminum (0.008, 0.020, 0.040 EDM notches)f.Teflon Tape, refer to Table 1-8g.Aircraft Marking Pencil, refer to Table 1-86.9.3.2Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. A partial inspectionfor cause (visual indications, sites of mechanical damage, corrosion, etc.) may be performed on all exposed surfaces ofthe installed part using this procedure. If required, the yaw/pitch coupling link shall be removed in accordance with theapplicable technical manuals listed in Table 1-1.6.9.3.3 Access. Access is through the controls/accessories sliding cover (Figure 1-4, Item 3T-4T-2).6-16
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