Predicted departure has altered again to 2030 hours. If QF (or any airline) advise late in the peace re a delay (as opposed to giving many hours' notice), it can be a sign that the aircraft is faulty. Not a given - maybe a key crew member has fallen sick at the last minute, or one of 50 other reasons - but concerning if a pushback keeps being altered, as it may be a sign that 'the issue' is taking longer than expected to fix.QF73, presently the 1740 hours SYD to SFO B744 has been pretty good timewise lately but Friday 13 September is an exception.
The flight was showing as punctual when I checked an hour ago but departure has been suddenly changed to a predicted 1930 hours this evening. Estimated arrival is 1545, 105 minutes late.