"Positive radar control" - archaic & obsolete. FAA (Possibly remnants of the old order) may still at times use it. Yup, even the FAA have moved on!
'flyburg', youre spot on! - Radar Control and left on FLt PLN'd Route/Path - crew responsible for terrain. Once taken off FLt PLN'd Route/Path..i/e; - receiving radar vectors - ATC responsible for terrain.