Originally Posted by
shuuy
On SYD-MEL, what I've found: 330s are usually either (a) positioning for trans-Australian and (b) points of peak demand (bearing in mind there are 26 non-stop flights each way daily - one of the busiest air routes in the world).
As a result, 330s are usually morning (8 / 8.30) or evening (5 / 5.30 / 6). Outside these times, very unlikely. I fly this route weekly and never have been upgauged to a 330, only down.
There are some midday flights and afternoon flights as well. From memory midday and 12:30PM and returning 2:30PM from MEL.
You really need to check each flight individually.