Qantas grounded its Airbus A380 superjumbos until further notice on Thursday, a week after a mid-air engine blast prompted serious safety worries over the world's biggest passenger jet.
The Australian carrier revamped its flight schedule to exclude the six flagship A380s, potentially for "weeks", after the blow-out which also led to Singapore Airlines putting three of its superjumbos out of action.
A spokesman told AFP that Qantas's A380s, which service long-haul routes connecting Australian cities with Los Angeles and London, would not be used for at least a few days.
"We're not really putting a time-frame on it at the moment. The situation's really fluid," he said. "It's (the relaunch) unlikely to be within the next couple of days, beyond that we're unwilling to say."
Qantas is among a group of carriers conducting urgent safety checks of the A380s' Rolls-Royce Trent 900 engines as investigators work to determine what caused last Thursday's blow-out over the Indonesian island of Batam.
The airline said its new schedule would minimise delays which have affected thousands of passengers, and suggested it could be in place for weeks.
"The new forward schedule enables Qantas to accommodate customers on services across its entire international network over the coming weeks, regardless of when A380 aircraft re-enter service," a statement said.
The comments are the first clues on when the fleet will be re-introduced since chief executive Alan Joyce said on Monday it would be grounded for at least another three days, following the discovery of oil leaks in three engines.
Qantas said it was testing how the engines perform under "operational conditions", adding that the inspections conform with a new directive issued by the European Aviation Safety Authority for all Rolls-Royce Trent 900s engines.
"Qantas is continuing an intensive inspection program on all Rolls-Royce engines in its A380 fleet and Qantas engineers have removed three engines to undertake further examination," the statement said.
Qantas' A380 aircraft will not return to service until there is complete certainty that the fleet can operate safely," it added.
Singapore Airlines grounded three of its A380s on Wednesday to replace engines after finding unexpected oil stains during tests, while Germany's Lufthansa said it would replace one A380 engine as a precaution.
Britain's Rolls Royce said Tuesday said the engine explosion was "specific to the Trent 900" in an update explaining it had made progress in understanding what had caused the QF32 blast.
Airbus, a unit of European aerospace giant EADS, has been flying the double-decker A380 for almost three years without major incident.
On Wednesday, Chicago-based Boeing halted test flights of its new 787 Dreamliner this week after an in-flight fire prompted an emergency landing, a fresh setback to the troubled jetliner project seen as a rival to the A380.
Qantas shares were five cents or 1.79 percent higher at 2.85 dollars (2.50 US) on Thursday.