You are onto it, alphacentauri. VH-OZY is not up to snuff.
And mikewil, you are onto it too; in fact, the IREX does not presently examine anything to do with RNAV's, ADSB requirements, RNP.... It seems to be almost hopelessly out of date in this area.
It does, however, address the Part 61 reg's; at least with respect to the currency requirements for IFR flight and for various approaches (and while not specifically for RNAV's of course, the same rules apply as for VOR approaches).
I suppose it was too much to hope for that someone who might have the inside track at CASA would chime in on this.
