If there's an RA in C ... someone has made a mistake
People would be surprised how often RA's occur when there were no 'mistakes'
and 'no breakdown of separation'. High closure rates [vertical and horizontal] with 1,000ft separation being applied i.e. one descending to FL150, and one climbing to FL140 where both are going to level off not that far from crossing. In fact in earlier and simpler versions of ACAS, it was possible for a rate of closure to induce an RA instruction [to both aircraft ACAS equipped] that voided the 1,000ft separation being applied, with the aircraft ending up climbing and descending through each other and their cleared [and separated] levels as a result.
Australian Manual of Air Traffic Services
4-10-250 Nuisance Advisories
Nuisance Advisories can occur even though standard separation exists. Do not immediately assume that separation has been lost, or that you are at fault, when a pilot reports manoeuvring in response to an RA.
4-10-260 Controller accountability
Note: A Controller is not subject to disciplinary action in the event of an accident or incident arising from an aircraft deviating from an ATC clearance or instruction as a result of an RA, provided that the occurrence was not the result of an incorrect clearance or instruction from the Controller.
Not sure how the tea and bickies would pan out after the fact in Australian
surveillance covered Class E [or G for that matter] though
I remember reading somewhere [can't put my finger on it just now] that 1,500ft was being suggested [for CTA/R] where high closure rates
might result in ACAS getting excited and deciding independently to give everyone involved a heart stop/start.
Edit: Sorry
ferris, had not seen yours before I hit submit
