Cathay Pacific Airways is investigating the involuntary in-flight shutdown on 11 November of a Rolls-Royce Trent 700 engine, which forced the crew of one of its Airbus A330-300s to return to Saigon shortly after take-off.

The engine suffered a suspected internal gearbox failure as the aircraft reached top-of-climb at 37,000 ft (11,300m). Cockpit instruments indicated a fall in fuel and oil pressure and the engine subsequently stalled.

After twice failing to restart the powerplant, the A330 crew elected to return to Tan Son Nhat International Airport and land with one engine. The engine was removed from the aircraft and flown back from Vietnam to Hong Kong for a full tear-down and inspection.

Investigations are understood to focus on a bearing failure in the gearbox area and possible radial driveshaft decoupling. Cathay sources confirm that the engine's master chip-detector found a sliver of detached metal.

The incident was the second recorded inflight shutdown of a Trent 700 since the engine entered Cathay service in February 1995.

R-R says that the failed part has been returned to its headquarters in the UK for inspection, and confirms that the failure occurred "in the accessory gearbox area". The company adds: "It hasn't happened before, and we're still not clear on the precise cause."

Meanwhile, Cathay and Dragonair are halfway through a rolling programme to modify the thrust reversers on their Trent 700s. Some of the early-build engines are understood to have suffered thrust-reverser failures, because of problems experienced with the lockout mechanism. A third, "tertiary", lock was added to the thrust-reverser mechanism late in the design cycle, as a precaution in the wake of the 1991 Lauda Air Boeing 767-300ER crash which was caused by the uncommanded in-flight deployment of a thrust reverser.

Modifications are now being incorporated into new-build engines before delivery.

The modification involves "-refining the position and alignment of the tertiary bolt", says R-R. "The upgraded units are not causing any problems," it adds.


Source: Flight International