QF 446 then QF 552 at Sydney
Melbourne → Sydney → Brisbane
Timetable, Sydney time
14:25QF 446 from Melbourne at the gate
20:45QF 552 to Brisbane leaves the gate
6 h 20 apart on the timetable
Sydney’s board shows about 68% of departures at their timetable time, so delays of a few minutes don’t show here.
The last days
QF 446 and QF 552 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.