hi Dick,
Wizofoz is mostly correct, as was TopDrop.
There are 5 special helicopter procedures in NQLD paid for by QLD rescue and designed in 2002 to special criteria. several in NSW [2001] and another recently in northern NSW.
Until just recently CASA was the holder and distributor of these procedures. The requirement was that the procedure had to be included in an ops manual and that all pilots had to be checked out for the special requirements of the approach [operation of visual approach area - VAA, or special low vis procs]. some of this info is on the CASA web site.
The two approaches mentioned here YATN and YIGM are to unlicensed fields which don't get a full notam service and that is one reason they are helicopter only. there is also a requirement to regularly check the landing areas before use.
The CASA officer who drafted the regulation left CASA and the remaining officers decided they didn't want the safekeeping of the procedures, so they were incorporated into DAP with a warning 'CASA approved operators only'. I believe this was their reasoning [read - I'm not sure of their logic]
Dick, if you want to fly these procedures YOU must get the appropriate training AND approval to use your 'IFR twin heli'.
Will there be more and more approaches with similar restrictions?
Dick, you know there already are. RNP-AR procs for QF and GLS procs in YSSY also for QF.