TM 1-1520-265-23
5.5.3.3 Access. Access to the aft engine mount strut is through hinged engine cowls (Figure 1-4, Items 3T-5 and 4T-8).
WARNING
Maintenance Platforms/Workstands
Use only appropriate platforms, workstands, or other approved locally procured stands and
restraint equipment when working above 10 feet on helicopters in a nontactical environment.
Otherwise, personnel injury could result from accidental falls.
5.5.3.4
Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
5.5.3.5
NDI Equipment Settings. Refer to Magnetic Particle Method, paragraph 1.4.8.
5.5.3.6
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 5-5.
a.
Select AC on the AC/DC power switch.
b.
Place probe/yoke on part in position I 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 5.5.3.8.
f.
Repeat steps a. through e. for positions 2 and 3.
g.
Repeat steps a. through f. for each strut.
5.5.3.7
Marking and Recording of Inspection Results. Mark and record inspection results as required by
paragraph 1.3.
5.5.3.8
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.
5.5.4
Backup Method. Fluorescent Penetrant, refer to paragraph 1.4.7.
5.5.5
System Securing. Clean the struts thoroughly to remove all residual magnetic particle media. Refer to
Post Cleaning and Restoration of Part or Area After NDI, paragraph 1.4.f16. The engine mount struts, if removed,
requires installation in accordance with the applicable technical manuals listed in Table 1-1.
5.6 AFT ENGINE MOUNT FITTINGS (MT).
5.6.1
Description (Figure 5-1. Index No. 6). The aft engine mount struts are attached to the aft mount fittings
(two inboard and one outboard) which are secured to the airframes.
5.6.2
Defects. Cracks may occur anywhere on the aft engine mount fittings. No cracks are allowed.
5-9
