Earlier today (Tuesday 11 April), QF127, the first of two QFs to HKG for the day departed at 1108, 68 late with arrival suggested as 1810, 50 minutes behind.
The more than 12 hour late QF12 into SYD on Tuesday 12 April (A388 VH-OQF) was predicted by QF to land at 1840 but it has lost a little further time, overflying the airport from
the west at 1840 and then being likely to land from the north at around 1849 after some impressive fancy footwork.
By the time it gets to the terminal (maybe between 1855 and 1900 hours), the chances of a 2030 hours departure look slim: 2100 might be more realistic, 310 minutes late. This then converts into at least four hours late into LHR on Wednesday morning, 12 April.
In a new delay, QF12 ex LAX on Monday 10 April (the 2230 hours) has been altered to depart at 1100 on Tuesday 11 April, presumably due to the crew needing minimum mandated rest. Wednesday 13 April SYD arrival is estimated at 1835, the same as today's late arrival.
These 12 hour delays may be OK at a pinch for 'higher status' passengers who, if seats are available, may be transferred to QF94 or QF16 (to MEL or BNE respectively) and then on a domestic flight to SYD, but pity the no status leisure mum travelling with a child, or elderly grandparents. Sure, they may receive an overnight hotel room and meals, but many might prefer to be at their destination.
This is the first instance I can recall of QF12 being badly late on two consecutive flights.
There is yet to be publicly displaying information as to whether QF1, 7 or 11 will be delayed in departing SYD tomorrow afternoon (Wednesday 12) due to QF12's more than 12 hour late predicted arrival.