On the MD80 (and all DC9's) the aircraft shifts to air mode with nose strut extension.
In fact, just the other day we had a MD80 that had several strange symptoms (inappropriate probes being heated, ART not arming, etc.) and when I performed the external preflight the nose strut was overserviced to the point the scissors was almost completely extended. Therefore the aircraft thought it was in the air and activated some systems not on the main gear switch.
It would be difficult to load a MD80 aft enough to get the nose light with a 160 seat configuration, when I flew charter MD80's we were almost always nose heavy if we had anything besides the aft cargo bin loaded.
doodah
