...Just wondering what flight forms QF23 each day as it looks like it is constantly delayed over the past month or so.
daturtle, QF23 always forms flight QF24 in Bangkok, as the latter is the redeye back down overnight to Sydney.
I suspect you mean 'what flight is QF23 formed by each morning?' (that is, in Sydney).
You can look this up. Just type in 'QF23' to Google, Bing or other search engine.
Then find the Flight Radar 24 listing. Open it, and scroll down to the last few days' departures. You will find an aircraft registration (such as 'VH-QPA' next to each day. Click on it, and by working backwards you can see which flight formed QF23.
The answer seems to be that it varies. Mostly the flight is an A333 but during teh next week more A332s are rostered for some reason.
This morning, it was A332 VH-EBL that arrived in SYD on QF408 (ex MEL) seven minutes late at 0832 (FR24 shows '0827' but five minutes to get from touchdown to the airport gate must be added). It then would have had to be hauled across to the international terminal: this takes time as you know.
(A332 VH-EBL is one of the four A332 aircraft - thank you, mannej, as it had thought it was only two - aircraft that are suitable for the SYD - PEK QF107/QF108 rotation as they have larger galleys and better crew rest facilities, but these flights were planned to not operate yesterday. EBG and EBL are referred to by AFFer moa999 as 'unrefurbished.')
Yesterday (21 August), QF23 was A333 VH-QPB that had arrived in SYD on the previous evening as QF462 (ex MEL) at 2022, so in that case it enjoyed 13 hours plus overnight in Sydney before it was due to depart for BKK. This maximises the chance of a punctual departure.
On Friday 18 August, another day when QF23 ran late, it was formed by QF130, the redeye from PVG in mainland China,. arriving SYD at 0837, 12 minutes late. Although in that case the arrival and departure were at the international terminal, it had little hope of being on time and took off for BKK at 1054, arriving the Thai capital at 1734, 54 late.
But it then upon coming back to SYD 'formed its own' - QF24 became QF23 on Saturday morning, so it was only 17 late in arriving the gate at Bangkok.
As you can see there's no discernible pattern.
VA helpfully seems to give FR24 its aircraft rosters for a few days in advance, and while it doesn't always stick to these, they can be very helpful. QF however does not. You can compare gate numbers allocated through QF website's flight status and usually work out which aircraft is going where, but that can be tedious.
If time is important, TG may be a better choice.