QF9 was about three and a half hours into its flight to Dubai from Melbourne when vibrations become apparent in an engine.
The decision was then made to return the flight to Sydney rather than Melbourne as it would position the A380 for immediate engineering attention and minimise passenger disruption and inconvenience.
Because there was no emergency or safety issue with the A380 it then had to take its turn at peak hour for international arrivals when the Sydney jet curfew ended at 6 am.
The passengers, who were able to dine, sleep or watch movies or chat among themselves, have now deplaned refreshed and eager to continue their delayed journeys, almost certainly, in another aircraft.
Photo - Flightradar24