Australian officials probing a Qantas A380 engine blast last month reported a "critical safety issue" with the Rolls-Royce turbine Thursday, which they said could lead to "catastrophic engine failure".
The Australian Transport Safety Bureau said a misaligned component had thinned the wall of an oil pipe in the engine, causing "fatigue cracking" that prompted leakage and a fire "central to the engine failure".
"This condition could lead to an elevated risk of fatigue crack initiation and growth, oil leakage and potential catastrophic engine failure from a resulting oil fire," the ATSB said, noting it was "understood to be related to the manufacturing process".
The Bureau issued a directive urging Rolls-Royce to "address the safety issue and take actions necessary to ensure the safety of flight operations in transport aircraft equipped with Rolls-Royce Trent 900 series engines".
Qantas said it would immediately conduct further engine investigations as a result of the findings, but stressed it was just a precautionary measure and "there is no immediate risk to flight safety".
"Qantas currently has two A380 aircraft in operational service, following the grounding of the fleet on 4 November. Both A380 aircraft will be inspected at the Qantas Jet Base in Sydney," the airline said.
"Inspections will commence on Thursday afternoon."
The flagship carrier said it would determine whether further action would needed after inspections were complete and it had consulted both Rolls-Royce and regulators.
"Qantas does not anticipate at this stage that the inspections will have an impact on international services. However, contingency arrangements will be in place, if needed," it said.
The findings come just five days after Qantas resumed A380 flights, though the carrier has barred the superjumbo from trans-Pacific trips to Los Angeles due to the extra engine thrust required.
It had grounded all six of its Airbus superjumbos after the November 4 blast over the Indonesian island of Batam, which forced an A380 to return to Singapore airport trailing smoke.
Checks revealed problems with 16 of the total 24 Rolls-Royce Trent 900 engines powering Qantas's A380s - four per plane - meaning the turbines would have to be replaced or modified.
Singapore Airlines replaced one engine each on three of its 11 A380s as a precaution after the Qantas incident and said Thursday's news was "really nothing new" and would not affect its flights.
"We are already complying with the recommendations from inspectors...This is an ongoing process," an airline spokeswoman told AFP.
German flag carrier Lufthansa, which also uses the Trent 900 on its fleet of four A380s, has replaced two of the engines, with Qantas last month warning as many as 40 units across the three airlines may have to be replaced.
Airbus has vowed to seek compensation from Rolls-Royce.
The double-decker A380, which carries 525 passengers and weighs 560 tonnes at takeoff, was hailed as the future of long-haul aviation at its commercial launch in 2007.
Qantas chief Alan Joyce on Saturday said he was "100 percent comfortable" with the A380s' operation. Australia's national carrier, it has has never suffered a fatal crash in the jet age.
The ATSB said it would hand down its full preliminary report into the incident on Friday.