TM 1-1520-265-236.20.3.7. Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph1.3.6.20.3.8. 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.6.20.4. BackupMethod. None required.6.20.5. SystemSecuring. Clean the lateral bellcrank thoroughly to remove all residual magnetic particle media. Referto Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The lateral bellcrank, if removed, requiresinstallation in accordance with the applicable technical manuals listed in Table 1-1.6.21. AFT BELLCRANK (MT).6.21.1. Description(Figure6-1.IndexNo.21). The aft bellcrank, supported by the bellcrank support (bridge) in theswashplate linkage installation, transfers flight control movements through a connecting servo link to the main rotorswashplate. It is machined from a 4340 steel forging, cadmium plated, and protected by epoxy primer and polyurethanepaint.6.21.2. Defects. This inspection is used to verify crack indications found visually on the aft bellcrank. Inspect allreworked areas for cracks. Inspect aft bellcrank lug and rib surfaces. Visually inspect bellcrank flanged pivot bushings.No cracks are allowed.6.21.3. PrimaryMethod. Magnetic Particle.6.21.3.1. NDIEquipmentandMaterials. (Refer to Appendix B.)a.Magnetic Particle Inspection Probe/Yokeb.Magnetometerc.Black Lightd.Fluorescent Magnetic Particles, refer to Table 1-8e.Consumable Materials, refer to Table 1-8f.Aircraft Marking Pencil, refer to Table 1-8NOTEHand-held magnetic coil may be used. Refer to paragraph 1.4.8.1.2 and Figure 1-6.6.21.3.2. Preparation 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 applicable positions of this procedure. If required, the aft bellcrank shall be removed inaccordance with the applicable technical manuals listed in Table 1-1.6.21.3.3. Access. Not applicable.6-41
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