Clarifying details about the oil feed problem that caused the uncontained Rolls-Royce Trent 900 failure on a Qantas Airbus A380 in November, the engine manufacturer says: "It is not true that we knew about a problem in the A and B versions of the engine and went on to correct it in the C version. There has been no design change relevant to this failure between A, B and C versions of the engine."

R-R added that the C version is not, however, vulnerable to the same type of failure, but the company refused to describe the modification that made the C version more robust in this respect. Since a R-R spokesman said this to Flightglobal, however, Rolls has stated if that is what was said during the interview, "some lines must have got crossed". So the status of the C version regarding a QF32-type incident remains unclear.

On the general situation regarding the future of the engines found to be at risk, R-R says it knows it has definitely found the fault that caused the uncontained failure, namely a fatigue-induced crack in a stub-pipe that feeds oil into the intermediate compressor bearings. An internal oil fire resulted, leading to the uncontained engine failure which also seriously damaged the airframe.

R-R says it has addressed the problem through inspecting all the Trent 900s in service, and instituting a programme that involves "replacing the relevant module". The company would not say whether the module referred to is the stub pipe itself, or an associated component that caused the stress that led to fatigue cracking in the stub pipe.

Meanwhile R-R points out that only Qantas elected to ground its A380 fleet. Singapore Airlines and Lufthansa did not do so, but chose to continue operations following prescribed engine checks.

Source: Flight International