TM 1-1520-253-23
6.3.3.2 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance. Partial inspection for
cause (visual indications, sites of mechanical damage, corrosion, etc.) may be performed on all exposed surfaces of the
installed part using this procedure. if required, the connecting link shall be removed in accordance with the applicable
technical manuals listed in Table 1-1.
6.3.3.3 Access. Access is obtained through transmission work platforms, flight controls closet panel, or cockpit. See
6.3.3.4 Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
6.3.3.5 NDI Equipment Settings. Refer to Magnetic Particle Method, paragraph 1.4.8.
6.3.3.6 Inspection Procedure. A magnetic field shall be applied to the part perpendicular to the orientation of possible
cracks. Positions for this inspection are illustrated in Figure 6-3.
a. 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 media
momentarily before removing the current. Current should be applied for no more than five seconds.
d. Inspect for cracks using the black light.
e. Demagnetize before moving to the next position. Refer to paragraph 6.3.3.8.
f. Repeat steps a. through e. for Positions 2 and 3.
6.3.3.7 Marking and Recording of Inspection Results. Mark and record the inspection results as required by paragraph
6.3.3.8 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.
6.3.4 Backup Method. None required.
6.3.5 System Securing. Clean the connecting link 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 connecting link, if removed, requires
installation in accordance with the applicable technical manuals listed in Table 1-1. Secure applicable work platform and
panels.
6.4.1 Description (Figure 6-1. Index No. 4). Control inputs from the cockpit are transmitted through mechanical linkage
to the Integrated Lower Control Actuator (ILCA). The ILCA then transmits individual control motions to the first and
second stage mixing units. The mixed outputs are then transmitted through a series of push-pull tubes to the upper dual-
boost actuators attached to the forward and aft swashplates.
6.4.2 Defects. This inspection is to verify cracks found visually. No cracks are allowed.
6.4.3 Primary Method. Fluorescent Penetrant.
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