A Qantas Airways A380 experienced a partial power loss during a flight on 15 February after encountering problems with a component in the aircraft's Rolls-Royce Trent 900 engine.
The Australian Transport Safety Bureau (ATSB) is investigating the incident, which took place near New Delhi during a Singapore-London Heathrow flight. The aircraft's registration is VH-OQC.
"During the cruise the crew observed a gradual decrease in the oil quantity for the number four engine. As a precaution the engine was reduced to idle for the remainder of the flight," says the ATSB.
"A subsequent engineering inspection found that the fitting of the external HP/IP [high pressure / intermediate pressure] oil line had less than the required torque."
The aircraft involved in the incident was built in 2008, according to Flightglobal's ACAS database.
The Trent 900's HP/IP bearing module has been linked to last November's uncontained engine failure on a Qantas A380. In a report on the incident released last December, the ATSB says a manufacturing defect led to cracking within a stub pipe that feeds oil to the HP/IP structure, resulting in oil leakage and an engine failure.