Problems with the A380 engine cost Qantas AU$55 million (£34.2m) in the first half.
An explosion in one of its Rolls-Royce engines meant the airline had to ground its A380 aircraft last November.
Qantas is still in talks with Rolls-Royce over compensation and has not ruled out taking legal action.
It warned there would be another AU$25 million (£15.5m) charge in the second-half results because of the problems.
Despite the disruption, Qantas reported that its first half net profits had risen four-fold to AU$241 million (£150m).
Underlying profit before tax rose 56% to AU$417 million, as sales grew 10% to AU$7.59 billion over the second half of last year.
Qantas predicted 2011 full-year profits would be considerably up on last year, but said profits would be impacted by high fuel prices and the recent floods in Queensland.
By Bev Fearis
