A Qantas Boeing 747-400, registration VH-OEH performing flight QF-73 from Sydney,NS (Australia) to San Francisco,CA (USA), was enroute at FL310 about 230nm northeast of Sydney when the crew decided to turn back and return to Sydney due to a problem with the autopilot. The aircraft dumped fuel and landed safely back on Sydney’s runway 16R about 2 hours after departure.
Passengers reported the climb had been unusually bumpy. Some time later the crew announced they would return to Sydney because the autopilot wasn’t working. On the ground maintenance worked on the aircraft, passengers understood a part of the autopilot was replaced, then departed again.
The airline reported a technical issue which was not a safety issue prompted the return of the aircraft.