This task cannot be performed without the special tools listed in the technical manual.
Ensure their availability and serviceable condition. These required items are:
Nitrogen, 184 cubic feet, cylinder (NSN: 6930-00-782-2643)
Hose assembly, purging (NSN 4760-01-040-9323)
Familiarity with the viewer infrared AN/PAS-7A is necessary to effectively perform this
task. Figure 3-1 and A illustrates the primary controls and indicators of the AN/PAS-7A.
Figure 3-1. Viewer, front view