Compared to Queenstown, there is not one instrument approach in this country I would put in the category of 'terrain challenged'. The idea that we need RNP-AR or BARO-VNAV to solve our terrain problems is quite frankly horse-s**t.
The argument for WAAS was run and lost many years ago. It is true that CASA signed up to the ICAO mandate and then had a coronary when they discovered the cost. The cheapest and best solution (according to them) was BARO. This was considered the best because Airservices would do it for free. Make no mistake there are about 90 BARO designs sitting on a desk in Airservices waiting to be published, the hold up is CASA as they cannot decide how to validate them for publication (lets ignore the fact that NZ does not validate theirs). The delivery of BARO approaches was to have been finished by now.
Now the focus shifts back to WAAS, a little less expensive than previously advised, but the big end of town are not equipped for WAAS, and they are primarily paying the bills.
In short WAAS would service a lot of aerodromes for the GA market, but they won;t pay and the big end of town don't go to these places. BARO/RNP_AR would service major airports but would not fulfill our agreement with ICAO and cannot be used by non FMS eqquipped acft.
QANTAS spearheaded RNP_AR because CASA was holding off for WAAS, and QANTAS knew it would never come. Unfortunately QANTAS main aim was efficiency and minima, the result was a stack of RNP_AR approaches that are basically useless in an ATM environment. I know this because Airservices has just been asked to replace them all with public AR criteria approaches that work. The first 3 public RNP_AR procedures on mainland Australia have just been published with more to come.
Remember that QANTAS spearheaded RNP in AUS, and paid for the RNP AR procedures. ASA and CASA are not prepared to setup or pay for the obstacle assessment requirement oversight, so QANTAS is paying for the obstacle assessment, NOTAM, and navdatabase oversight on their own...
This statement is full inaccuracies....there is no extra obstacle oversight requirement for an RNP-AR beyond that which exists for any other approach.
My honest opinion....we won't be seeing WAAS anytime soon. The technology is already old, and the airlines won't pay for something they cannot use. What will we see? Its hard to know...