By the way, I use the term IRS on purpose. B742 and L1011 era had INS fitted. FMS did not appear until the late 1970s.
Except for SaudiArabian aircraft.
These aircraft were fitted with three Litton ISS units (not capable of stand alone navigation), which in turn provided data to two Hamilton Sundstrand FMS units (far more useful than their Smiths cousins), and this whole kit and caboodle also included a 12 inch diagonal (CRT) moving map, all in one neat package.
The first and finest available, anywhere, circa 1976.
Aircraft type?
Lockheed TriStar.
