L-852A-D, J & K ITCF, F-Range, ICAO LED Taxiway Centerline Light
96A0460 Rev. C
Maintenance
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20
2.4.2.2 Replacing the Prism
Replace the prism if it is broken or its surface is badly pitted or scarred.
To replace the prism, perform the following procedure:
1. Remove the prism-clamp and prism-keeper plate secured in the inner pan assembly.
Figure 10:
Replacing Prism
Figure 11:
Top Assembly
2. See Figure 10. Remove the flat seal.
3. See Figure 11. Push the prism with the sock seal towards the inside of the cover.
4. Clean and degrease the prism chamber with any effective solvent.
NOTE:
Never use any abrasive substance. This will scratch or frost the prism. Use mineral
spirits, or alcohol.
5. Apply a thin layer of lubricant MOLYKOTE BG87 INERTA or MOLYKOTE BG88 INERTA
in the prism chamber using a small brush.
6. Install a new sock seal over the prism.
7. Push the prism/gasket assembly in the prism pocket from the inside and clean the inner
surface of the prism.
8. Install a new flat seal over the prism-keeper plate.
9. See Figure 10. Reinstall hardware with the Phillips pan head screws. Apply a drop of
sealant Loctite 270 (or equivalent) to the last threads. Torque to 31
±
4 inch-pounds
(3.5
±
0.5 N•m).
Sock Seal and Prism
Flat Seal
Prism-keeper Plate
Prism-clamp
