"They are trying to limit stressing the engine to its maximum, to prevent any aggressive deterioration or anything like that," Marosszeky said. "It is a very wise decision. You don't want to operate something at its maximum thrust capability then find out that you are prematurely creating a problem."
In addition to the two A380s from the existing fleet returning to the skies, Qantas would take delivery of two new superjumbos from Airbus that the airline will put immediately into service, Joyce said. Qantas expects to by flying four A380s by the time the busy Christmas holiday period starts.
The rest of Qantas' fleet will remain on the ground as it waits for new or modified engines to be supplied. So far, 16 engines on Qantas planes have been removed, Joyce said. The damaged plane will remain in Singapore for repairs.
Qantas has declined to say publicly what its thrust settings for its A380s are. The airline reportedly uses a maximum thrust setting of 72,000 pounds for A380s taking off on the two Australia-United States routes. That's below the engine's certified maximum of 80,000 pounds, according to Rolls-Royce documents.
Rolls-Royce has indicated that number to be 40 engines worldwide.
Engineers have discovered oil leaks in the turbine area of three engines on three different A380s.
Rolls-Royce has identified a faulty bearing box as the cause of the oil leak problem.
Delays have hurt more than just profits, denting Airbus' reputation and allowing U.S. rival Boeing Co. to sneak into the top sales spot in 2006.