5.13 HIRSS AND NACELLE FAIRING SUPPORT MOUNTS (PT).
5.13.1 Description (Figure 5-1, Index No. 13). The hover infrared suppression system is contained
within the HIRSS module. Parts of the support mounts are: fail-safe plate, rear suppressor support
fitting and link, lower nacelle support fitting and link, and upper nacelle support fitting and link.
5.13.2 Defects. Defects can occur anywhere on the surface of the described parts. No cracks are
5.13.3 Primary Method. Eddy Current.
184.108.40.206 NDI Equipment and Materials. (Refer to Appendix B.)
a. Eddy Current Inspection Unit
b. Probe, straight, shielded surface, 100 KHz-500 KHz
c. Probe, right angle, shielded surface, 100 KHz-500 KHz, 90_ 1/2 inch drop
d. Cable Assembly
e. Reference Block, three-notched aluminum (0.008, 0.020, 0.040 EDM notches)
f. Teflon Tape, refer to Table 1-8
g. Aircraft Marking Pencil, refer to Table 1-8
220.127.116.11 Preparation of Helicopter. The helicopter shall be prepared for safe ground maintenance
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, paragraph 1.4.4.
126.96.36.199 NDI Equipment Settings.
a. Make the following initial settings on the Eddy Current Inspection Unit, NORTEC-19eII.
- 200 KHz
- 56_ Adjust as needed
- 80% Adjust as needed
- 20% Adjust as needed
b. Refer to Eddy Current Method, paragraph 1.4.11. Set up on test block as follows:
(1) .Null probe on test block.
(2) .Adjust phase as required to obtain horizontal lift-off.
(3) .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 1-7.)