segunda-feira, 8 de novembro de 2010

Qantas A380 Oil Found Where Shouldn't Be

The engine explosion on QF32 (Singapore to Sydney) on Thursday, the overheated engine on QF6 on late Friday from Singapore and the cockpit warning of a hydraulic problem on QF29 (Hong Kong to London) on the same day have overshadowed what should have been a weekend of celebration.

Qantas has one A380 in Singapore under investigation, one in Germany for servicing, one in Sydney and three in Los Angeles undergoing checks after the midair engine explosion on QF32.

Qantas CEO Alan Joyce told reporters inspections of three engines discovered oil "where oil shouldn't be" as Qantas and Rolls Royce engineers bear down on the possible cause of the failure. "These are new engines on new aircraft, they shouldn't have these issues at this stage so it's given us an indication of an area for us to focus into," Joyce said.
"On three of the engines what we have found is slight anomalies. Oil where oil shouldn't be on the engines, and we are just trying to check what the cause of that could be," Joyce said.
Air investigators have recovered almost half of a shattered turbine disc - a doughnut-shaped metal plate about a metre across - that blew out of the No. 2 engine on the Qantas plane Nancy Bird Walton last week and landed on Indonesia's Batam island.

The Trent 900 is the first engine in the Trent family to feature a contra-rotating high-pressure shaft providing a more efficient engine with lower fuel consumption and reduced weight. In addition, QUICK, an advanced predictive maintenance system, has been introduced to reduce maintenance disruption and improve time on-wing.
The engine has a baseline take-off thrust of 70,000lb and is certificated up to 80,000lb from the same bill of material. In testing, it has been run up to 93,000lb thrust.
Performance of the engine is exceptional, meeting or exceeding all of the next generation targets it has been set.

Key principles and benefits of the three-shaft engine:

• Shorter, stiffer shafts allowing improved performance  retention

• Optimised blade speeds improving engine efficiency

• Lighter weight engines resulting in higher revenue earning potential

• Modular design allowing easier maintainability

Engenheiros reportaram em 06 Novembro, que o disco da turbine intermediária de pressão do motor 2 falhou. A causa dessa falha está ainda sendo investigada. Uma vez que estava no solo a tripulação notou que eles não podiam “desligar” o motor 1 devido a avaria na fiação elétrica. Efetuaram Manutenção de Emergência, ‘afogando’ (aumentando a quantidade de combustível na câmara de combustão) o motor para 'desligá-lo'. O motor Trent 900 tem sido objeto de uma Diretriz de Aeronavegabilidade pela EASA (agência européia de segurança de aviação) solicitando que as projeções do eixo (parte que encaixa na fenda do eixo correspondente) que acopla na [turbina] intermediária de pressão, seja inspecionada por uso excessivo, as quais foram encontradas além dos limites materiais em alguns motores. Engenheiros estão olhando se estes problemas têm reaparecido novamente.

The engine came apart over the island of Batam and residents reported that debris rained over a wide area. The ATSB is hoping someone finds a missing chunk of turbine disc that departed the nacelle. "The recovery of that turbine disc piece could be crucial to understanding the nature of the engine failure, and may have implications for the prevention of similar occurrences in the future," the ATSB said in a statement. At least two of the engines with errant oil are in Los Angeles and have been removed from the aircraft for more detailed inspection.

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