ML RWY 34 has both GNSS & RNP approaches. They have the same MDA (330 ft) as the VOR approach. They have the same 3 deg approach path (naturally) and RNP approach seems to approximate the DME arc and transition of the VOR approach.
The RNP approach seems to remove the circle-to-land minimum altitude, which makes the Australian NVMC visual approach clearance requirement interesting.
As I understand it, the RNP requires CASA approval which is primarily about flight crew training and equipment certification. The RNP requires RF which is some sort of flight management system distance measuring function - I guessing DME based. I think this is an example of an RNP approach that could be flown with DME & VOR and doesn't require GPS
Correct me if I'm wrong, but I believe this is still a non-precision approach (which would require an additional height reference - typically a WAAS beacon).
The Thai incident was NVMC, so visibility & MDA were not an issue. The issue was the early & mid procedure altitude reference, which for the VOR approach is basically read the chart, read the DME and check the altimeter. For whatever the reason, the crew on the night (and a number of other crews by reference to ATSB reports) didn't do a very good job of this.
So, unless the RNP hardware feeds the flight director, then the Australian non-precision RNP approach isn't much of an improvement over either the VOR or the GNSS NPA. The main difference (I think) is that the FMS of a RNP aircraft will fly the curved transition.
As I understand it, the benefit of the ILS for all RWYS at ML is that the crew falls into a more practiced routine and gets vertical guidance. I don't think the Australian implementation of RNP achieves this.
I found a US FAA reference that says an ILS costs USD$3m to install and a US AOPA reference that suggests they cost USD$18,000 pa to maintain. If that is all it is - then why the fuss? Mildura is spending more than that on a new terminal building. If it costs significantly more in Australia, then we should hold the blowtorch to the belly of AsA and find out why they are so uncompetitive. - Or subcontract it to the FAA.