Sarcs, thanks for that info.
I was less confused because I learnt that my original premise was correct but that CASA believes that the supplement is flawed. Love to know why...
But then my confusion soared!
Earlier this year CASA conducted some initial simulator testing and this indicated that the cross wind limit may need to be reduced to 10kt in order to ensure the continued safe operation of SAAB 340 aircraft on the 18m wide runway at Coober Pedy.
I presume that this was in the SAAB engineering development simulator and
not in the common old garden variety pilot training simulator, since the data package in the latter is most likely
not to have sufficient fidelity to accurately replicate the effect of crosswind on Vmcg
nor is it tested for such.
How was the original 'flawed' supplement determined?
And another thing:
CAAP 235A-1 (0) clarifies that the runway width must be of a homogenous surface material. Coober Pedy's main runway currently consists of an 18m sealed section and 6m gravel shoulders on either side. This would be considered an 18m wide runway, not a 30m wide runway for the purposes of the new regulation.
I thought that in such circumstances we used to treat it as a 30m gravel runway (worst case) and plan accordingly. If you have a gravel runway certification, no drama...