I use my company ops as an example.....at the 1000ft(RA) gate the PM calls "one thousand"...the PF...calls "STABLE"... or ...UNSTABLE and correcting(whether it be be or altitude,speed etc)....@t the 500ft(RA) gate
I thought the radio altimeter gave the instantaneous height above the terrain immediately below the aircraft and therefore simply using 1000 ft (RA) would not necessarily be the height above the runway. Same with the 500 (RA) call. Obviously if the terrain below the aircraft on final approach is not dead flat and same altitude as the runway, the calls based on purely a radio altimeter read-out are superfluous and worse still potentially misleading. It is a wonder that the CAA have not commented on this during their audit of the company Ops Manual.
