What's this 500 ft above the step?
XXX,
Actually, yet another example of the rest of the world (including ICAO) being out of step with Australia.
A close perusal of the ICAO source docs., and of the AIPs of many other countries, including US, show that the whole volume of controlled airspace is available for aircraft operating in that volume.
In this case, aircraft operating in G (or F) are required to create the vertical buffer, and interestingly, it is not 500', but 700' (expressed in meters in the source docs.)
Thus, in US, UK etc, the lowest base of CTL will frequently be local ground level plus 1200', so that an aircraft complying with the vertical buffer of 700' will still be 500' AGL.
But, Australia has to be different!!
Tootle pip!!
PS: It seem like many of you need to re-read the criteria for VFR navigation ---- and I believe we are seeing incidents and accident starting to show up as being a result of blind reliance on GPS of doubtful standards (even some older TSOd equipment) and a far from complete understanding, on the part of many pilots, of the limitations of their equipment.