Two Qantas flights forced to return to Sydney with 'mechanical issues'

Two Qantas flights have been forced to turn around and return to Sydney as a result of separate “mechanical issues”.

Qantas flight A380 QF7 was first spotted by the 7 News helicopter dumping fuel off the coast after departing Sydney for Dallas/Fort Worth about 1.40pm.

Qantas said the captain of QF7 made the decision to turn around after “the flaps on the aircraft were unable to retract”.

“As the Dallas flight is our longest on the network the captain made the decision to return to Sydney," Qantas said in a statement.

After circling and dumpling fuel around Sydney and Wollongong, that plane safely touched down just after 4:30pm.

As all of this unfolded, a second flight, Qantas QF63 from Johannesburg to Sydney, also needed to return to Sydney due to a cracked pane of glass on the aircraft windscreen.

"An aircraft windscreen is made up of three layers of glass, the outer pane had cracked but did not compromise the integrity of the aircraft," Qantas said.

The aircraft was safe to continue to Johannesburg, Qantas said, but the captain made the decision to return and have the windscreen replaced in Sydney.

QF63 has already landed safely at the airport.

Operational teams are working to accommodate passengers or offer them transport home before replacement services are organised.