Vref+5,
Interested in your comments regarding VFR level compliance of the TCAS.
Around major airports the steps are VFR bases - i.e. 3500 is 'G 'OCTA , and 4000 is 'C' CTA - usually with inbound TCAS equipped aircraft 'sitting' on the step waiting for the next step, or rapidly descending towards it. I have probably only seen 1/2 dozen 'RA's' in that situation, normally because of excessive descent rates (excessive by the CPA calculation in the TCAS that is), but have never even had a query from the inbound aircraft when overflying with 500' level between and no ROD or ROC - not even a query on possible TA or PROXIMATE traffic.
Also, some of the equipment hanging around below the steps now is relatively high perofrmance in terms of achievable ROC - e.g. LNC4, SR20, Warbirds etc.
edited for formatting W
