SYDNEY: Two international Qantas flights suffered mid-air mechanical problems Friday and had to turn back to Sydney, with one unable to retract wing flaps and another suffering a cracked window pane, the Australian carrier said. Flight QF7 was enroute to Dallas, but the Airbus A380’s captain decided to head back to Sydney after discovering the wing flaps could not be retracted. “[This] means the aircraft can’t fly efficiently. As the Dallas flight is our longest on the network, the captain made the decision to return to Sydney,” Qantas said in a statement. The second flight, QF63 to Johannesburg, returned when “a cracked pane of glass on the aircraft windscreen” was found. “The aircraft was safe to continue to Johannesburg but the captain made the decision to return as the windscreen will be replaced at Qantas’ engineering base in Sydney.” Qantas said the Boeing 747-400 landed safely. Replacement flights were being arranged for passengers.