On Thursday 26 September, QF12, the 1810 hours crosscountry JFK - LAX pushed back at 1959, arriving at 2254, 114 late. This meant the connecting A388 on QF12 could not depart for SYD until 0039 on Friday (129 late) with Saturday 28 arrival at 0833, 123 minutes behind schedule.
While often in such circumstances it is not held, on this occasion QF94 (scheduled at 2240 ex LAX) was off blocks at 0055 on Friday so Saturday arrival is a predicted 0910 hours, 100 late.
'The 16' (formed by QF12) was of course also tardy, leaving LAX at 0117 (117 late) with BNE Saturday arrival at 0753, 108 late.
The reason behind all this late running was that on Thursday, QF11 (b789 VH-ZNH) departed LAX 101 late at 1001, arriving JFK at 1804, 84 late. It lost further time on the ground turning around to form 'the 12.' In turn, this was due to QF15 on Thursday departing BNE 121 late at 1221, arriving LAX at 0831, 151 minutes behind the timetable.
AFFer MEL_Traveller previously remarked this is common when QF11 is delayed arriving in JFK, although hardly restricted to JFK. Unfortunately like most transport modes when an aircraft is late arriving at a busy airport, delays can compound as the subsequent departure loses its (in airlines' case) slot time.