TAIL LANDING GEAR TRAILING ARMS (ET).
Description (Figure 4-1. Index No. 35)
. The tail landing gear trailing arms are the two lower arms attaching
the tail landing gear to the helicopter.
Defects. Defects can occur anywhere on the surface of the tail landing gear trailing arms. No cracks are
Primary Method. Eddy Current.
220.127.116.11 NDI Equipment and Materials. (Refer to Appendix B.)
Eddy Current Inspection Unit
Probe, straight, shielded surface, 100 KHz-500 KHz
Probe, right angle, shielded surface, 100 KHz-500 kHz, 90
1/2 inch drop
Reference Block, three-notched aluminum (0.008, 0.020, and 0.040 EDM notches)
Teflon Tape, refer to Table 1-8
Aircraft Marking Pencil, refer to Table 1-8
18.104.22.168 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 this procedure. If required, the tail landing gear trailing arms shall be removed in accordance with
the applicable technical manuals listed in Table 1-1.
22.214.171.124 Access. Not applicable.
126.96.36.199 4Preparation of Part. The part shall be thoroughly cleaned. Refer to Preparation of Part or Area for NDI,
188.8.131.52 NDI Equipment Settings.
Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-19ell.
- 200 KHz
Refer to Eddy Current Method, paragraph 1.4.11. Set up on test block as follows:
Null probe on test block.
Adjust phase as required to obtain horizontal lift-off.
Move probe over all three notches in test block. Adjust gain to obtain a three block vertical signal when
probe is passed over 0.040-inch notch in test block. (See the standard instrument display shown in Figure