The Nozzle Position Indicator shows the aperture of the engine's outlet-nozzle. In idle the nozzles are open.
When applying max. power the nozzles are closed. When the afterburner is activated, the nozzles are opened. The Nozzle
Position Indicator is the second instrument on the right side of the center console
The showed panel drawing is a drawing with can be downloaded from my page Documents,
plans and diagrams from the F-16