Besides VOR radial navigation in older MD-80 aircraft, what are the most common navigation systems on this type of plane? Are they mostly GPS or are INS and IRS used as well? Is the navigation system always linked to the autopilot NAV function, whatever the nav system is?
I suppose this can vary a lot from airline to airline and from series to series. I'm particularly interested in what airlines with large MD-80 fleets use, for example American, SAS and Delta, but it would be great to know about any operator.
Also, what does a PMS do compared to an FMS? I've noticed that some MD-80s have a PERF function on the autopilot panel (the DFGCP, right?), where other MD-80s have a VNAV button, and I think this has to do with the airplane having a PMS or a FMS. Older MD-80 flight decks don't even have this function at all.
Thanks a lot in advance for your replies. I'll just finish by posting 3 different MD-80 flight decks, but all of them belong to an MD-82 (my favorite airline first ):
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