When the F4 took over that slipped to RS15, mainly, IIRC, because of the time required to align the INAS platform.
I was a 111 Sqn Liney on Phantooms in the mid-eighties and when on Q the Ground Power was always plugged in & on to keep the INAS running. Sometimes a "leaky" jet was also hooked up to a set of nitrogen bottles too!
regards & happy 2012 to you !
Howie