The three operators of Rolls-Royce Trent 900-powered A380s are awaiting the outcome of preliminary investigations into the serious engine failure suffered by a Qantas aircraft on departure from Singapore on Nov 4.

The incident involved Qantas’s first A380 (VH-OQA), which was operating flight QF32 bound for Sydney, and was forced to return to Singapore’s Changi Airport after what CEO Alan Joyce described as an apparent uncontained engine failure. Joyce said the airline had suspended services by its other five A380s “until we're comfortable that we understand the reasons for this.”

As of last month, 20 of the 37 A380s in service were Rolls-powered, with lead operator Singapore Airlines having 13 in service, while Lufthansa had three.

The engine maker says in a statement that the in-service fleet of Trent 900 engines is “small and relatively new, and feels that it is prudent to recommend that a number of basic precautionary engine checks are performed. This process is now underway.”

Immediately after the incident, Singapore Airlines revealed it would delay all A380 flights pending the precautionary checks advised by Rolls and Airbus, but stopped short of a grounding.

Lufthansa had said it planned to keep its three A380s flying, and performed the required checks during normal turnarounds. However, it subsequently decided on the evening of Nov. 4 to replace the A380 on its overnight Frankfurt-Johannesburg flight with a Boeing 747-400.

None of the 440 passengers and 26 crew on board flight QF32 was injured. Debris from the engine cowling was recovered on the Indonesian island of Batam, just south of Singapore. Passengers photos show damage to the upper surface of the left wing caused by debris from the No. 2 engine. Other photos show blackened areas of damage near the rear of the Trent 900, including what looked like a hole near the top of the casing in line with the turbines.

One picture from Batam shows what looked like a segment of a disc from the engine’s turbomachinery, without blades attached, while another shows separated blades.

In January, the European Aviation Safety Agency issued an airworthiness directive (AD) for the Trent 900 engine intermediate pressure (IP) shaft which, if not performed, could result in an uncontained engine failure similar to those that have affected a Trent 1000 Rolls is developing for the Boeing 787. The AD says wear beyond normal limits has been identified on the abutment faces of the splines on the Trent 900 IP shaft rigid coupling on several engines during strip.

As the shaft-to-coupling spline interface provides the means of controlling the turbine axial setting, the wear through of the splines would permit the IP turbine to move rearward, the directive adds. This rearward movement “would enable contact with static turbine components and would result in loss of engine performance with potential for in-flight shut down, oil migration and oil fire below the [low-pressure] turbine discs prior to sufficient indication resulting in loss of [low-pressure] turbine disc integrity.”

Airbus notes that the aircraft (MSN14), which was delivered to Qantas on Sept. 19, 2008, had logged 8,165 flight hours and 831 flight cycles.

The Australian Transport Safety Bureau says it “is already working closely with its Indonesian and Singaporean colleagues and anticipates commencing its examination of the aircraft tomorrow, Friday, 5 November.”

The carrier says it has started its own investigation, and will be working with the Australian Transportation Safety Bureau.

Qantas dispatched a relief flight to Singapore on the morning of Nov. 5 (local time) to bring the A380’s passengers to Australia. The airline has also scrambled to cover flights affected by the grounding of its A380 fleet. It is working to get customers in Los Angeles who were booked on A380 flights onto other flights.

Qantas announced that four flights on its Australia-Los Angeles routes have been delayed by 24 hr. However, another Sydney-Los Angeles flight and a Sydney-Singapore-London flight are expected to operate on schedule using Boeing 747-400s instead of A380s. In addition, a British Airways 777 has been chartered to handle a London-Singapore flight, and a decision was to be made as to how to handle the Melbourne-bound passengers on this flight.