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Three disk fragments damaged Qantas A380 systems

Assessment of the Qantas Airbus A380 involved in an in-flight engine failure has revealed the extent of peripheral damage to the jet from ejected fragments.

While the Australian investigation team leading the inquiry has yet to produce a preliminary report, ATI has ascertained that three high-energy fragments were released by the intermediate-pressure turbine disk during the failure of the inboard left-hand Rolls-Royce Trent 900 engine on flight QF32.

Two of the three sections of disk debris cut through two wiring routes and this damage subsequently prevented the shutdown of the adjacent outboard engine after the aircraft landed at Singapore.

Sources familiar with the investigation state that the crew "had to manage a dynamic situation" as the A380 sustained structural and systems damage in several other areas.

While all flight-control surfaces remained available in the pitch and yaw axes, roll control was affected although it continued to be available through the inner aileron on the left wing, and the mid- and inner aileron on the right wing.

Several spoilers - four on the left wing, and five on the right - were also able to contribute to roll control. These spoilers were those activated by the 'yellow' hydraulic channel, one of two hydraulic systems on the type.

Slats on the aircraft - which are linked to the 'green' hydraulic channel - were jammed in the retracted position but the flaps, which are connected to both channels, were available to the pilots.

Loss of the slats and partial degradation of the roll control led the A380's flight-control laws to revert to 'alternate', while 'normal' law was retained in the longitudinal and lateral axes.

"Flight envelope protections were still active," the source states.

As the aircraft returned to Singapore following the engine failure, the autopilot remained engaged until the jet descended to about 700ft at which point the crew took manual control of the aircraft, with the flight directors on.

This also included manual control of the three remaining operational engines on the stricken aircraft. Flaps were in position '3', one stage from full deployment, the normal configuration for approach. The landing took place about 1h 40min after the failure.

Normal braking was available on the fuselage landing-gear bogies, including anti-skid, while alternate braking without anti-skid was available on the wing landing-gear. "The crew modulated braking in order to stop close to emergency services," says the source.

Airbus and Rolls-Royce simply state that they are assisting the Australian Transport Safety Bureau with the investigation and are supporting other operators of Trent 900-powered A380s.

Download Flightglobal's FREE Commercial Engines 2010 report which includes market share and technical data for the Trent 900.

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