Was YMIA a suitable airport for an alternate - width, weight, length, permission owners?? for your scenario.
Reading the ATSB interim report
http://www.atsb.gov.au/media/4479075...00_interim.pdf a few thoughts come to mind - including that YMIA was NOT a suitable alternate.
Biggest question (and likely gotcha) - who knew TTFs couldn't show PROBS?
Upon the issue of the 2100 TAF combined with the 'code grey' an alternate really ought to have been required but the TTF over-rid that. Did the BOM forecasters understand what they'd done by issuing a prob30 lasting for the same period that the TTF said all clear?
Did crew of VRK assume that because the TTF had no sign of fog then they were ok to continue past YMML diversion point.
How did VIR get so close to Adelaide without knowing about the amended TAF, METARS and ATIS?
Why did either crew consider YMIA as an alternate given it had TEMPO BKN 060 (edit:BKN006) on the forecasts they got at planning? Well below the alternate minima - as a TEMPO - have the METARs been relied upon too much?
From my reading of the report:
- BOM have let everyone down
- Not allowing PROB on TTF is a real gotcha (as such BOM should have erred on side of caution and not put TTF:NOSIG).
- Both crews seem to have relied on YMIA as their option (YIR may have had no choice) when it was inappropriate to do so
- Both crews don't seem to have been proactive in monitoring the deteriorating YPAD conditions (YIR especially) - I assume they had access to ATIS via ACARS?
- what on earth was the Virgin ops centre doing during all this
- the captain of YIR has been a little generous in allowing VRK to push in.