High Vertical Rates
It is generally acknowledged that, whilst changes made to TCAS II/ACAS II equipment design requirements have been effective in reducing the frequency of occurrence of RAs generated by high vertical rates, no further changes can now be made without degrading the safety benefit unacceptably.
ICAO is developing guidelines for operators, suggesting that they should authorise pilots to use a modest vertical speed throughout a climb or descent when the vertical interval is not large - such as a change of altitude in a holding pattern, or a step climb of a couple of thousand feet - and to specify how this should be accomplished. Operators will be encouraged to specify procedures appropriate to the type flown that pilots would use to reduce the aircraft's vertical speed when an autopilot is engaged.
Further information on what pilots should be taught regarding compliance with RAs and the need never to manoeuvre in a sense opposite to that posted by an RA (so as not to compromise compatible RAs) can be found in Flight Deck Forums >> Tech Log >> Tcas.