220.127.116.11. Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. A partial inspection
for cause (visual indications, sites of mechanical damage, corrosion, etc.) may be performed on all exposed surfaces of
the installed part using applicable positions of this procedure. If required, the main landing gear shock strut shall be
removed and disassembled in accordance with the applicable technical manuals listed in Table 1-1.
18.104.22.168. Access. Not applicable.
22.214.171.124. Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
126.96.36.199. NDI Equipment Settings. Refer to Magnetic Particle Method, paragraph 1.4.8.
188.8.131.52. Inspection Procedure. A magnetic field shall be applied to the part perpendicular to the orientation of possible
cracks. Positions required for this inspection are illustrated in Figure 4-25.
Select AC on the AC/DC power switch.
Place probe/yoke on part in position 1 as shown.
Press the test switch and apply a light coat of magnetic particle media at the same time. Remove the media
momentarily before removing the current. Current should be applied for no more than five seconds.
Inspect for cracks using the black light.
Demagnetize before moving to the next position. Refer to paragraph 184.108.40.206.
Repeat steps a. through e. for position 2.
220.127.116.11. Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph
18.104.22.168. Demagnetization. With the switch remaining in the AC position, place the probe/yoke legs in the same position
used for magnetizing. Press the test switch and withdraw the probe/yoke from the part for a distance of two feet before
releasing the switch.
4.25.4. Backup Method. None required.
4.25.5. System Securing. Clean the shock strut thoroughly to remove all residual magnetic particle media. Refer to
Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.16. The shock strut, if removed, requires
assembly and installation in accordance with the applicable technical manuals listed in Table 1-1.
4.26. MAIN LANDING GEAR WHEEL ASSEMBLY (ET).
4.26.1. Description (Figure 4-1. Index No. 26). The main landing gear wheel assembly provides a mount for the tires
and permits the helicopter to be rolled during ground handling.
4.26.2. Defects. Defects may occur anywhere on the surface of the main landing gear wheel assembly. Pay particular
attention to bead seat, bolt boss mating surfaces, and valve hole areas. No cracks are allowed.