TM 1-1520-265-23
2.17.3.7 Marking and Recording of Inspection Results. Mark and record inspection results as required by paragraph 1.3.
2.17.4 Backup Method. Fluorescent Penetrant, refer to paragraph 1.4.7.
2.17.5 System Securing. The bifilar vibration absorber, if removed, requires installation in accordance with the
applicable technical manuals listed in Table 1-1.
2.18 BIFILAR WEIGHT (UT).
2.18.1 Description (Figure 2-1. Index No.18). The bifilar weight is part of an assembly that pivots on two points at the
end of each bifilar absorber support arm.
2.18.2 Defects. This inspection is to detect manufacturing defects in the bond line between the two legs and the body of
the weight.
2.18.3 Primary Method. Ultrasonic 2.18.3.1 NDI Equipment and Materials. (Refer to Appendix B.)
a.
Ultrasonic Inspection Unit
b.
Transducer, 5.0 MHz,45s shear wave, 1/4 x 1/4 inch element
c.
Cable Assembly, BNC to Microdot
d.
Consumable Materials, refer to Table 1-8
e.
Aircraft Marking Pencil, refer to Table 1-8
2.18.3.2 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 applicable positions of this procedure. If required, the bifilar weight shall be
removed from the helicopter in accordance with applicable technical manuals listed in Table 1-1.
2.18.3.3 Access. Access to the bifilar weights is from the UR engine cowl (Figure 1-4, Items 3T-7 and 4T-8).
2.18.3.4 Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
paragraph 1.4.4.
2.18.3.5 NDI Equipment Settings.
a.
Make the following initial settings on the Ultrasonic Inspection Unit, USD-15S:
(SETUP - DEFAULT SETTINGS)
DIALOG ENGLISH
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