Posted: Sat Mar 01, 2014 7:37 pmI don't know the original source of this but take it as you will.
Qantas operates the Trent 972 engine, which delivers a maximum thrust of 72,000 lb. The only other current two Trent 900 operators, Lufthansa and Singapore Airlines, operate the Trent 970 with a maximum 70,000 lb of thrust.
That extra 2,000 lb on each engine is needed to get the A380 off LAX’s relatively short runways in a headwind with a full load for a 14 hour flight in light of Airbus adding structural weight to the A380 in 2007. Prior to that time Qantas planned to use the 70,000 lb Trent 900 variant.
However, the extra thrust exposes the engine to 540 psi at P30, which causes the engine to experience “high severityâ€, the affidavit says. Rolls-Royce’s interim suggestion to Qantas has to been to derate the engines in order to “reduce the engine pressure ratio in the ‘P30′ area of the engine and therefore increase the life of the oil transfer tubes within the HP/IP support structureâ€
The oil transfer tubes are the suspected cause of an oil leak that started a fire and then the uncontained engine failure. The derated thrust, however, reduces payload and makes the LAX-Australia route unprofitable.
The Trent 900 has had three modification standards: A, B, and C. Qantas and Rolls have agreed the carrier should not operate at all the “A modâ€. The “B mod†and “C mod†can be used, even for maximum thrust–but only 75 times. After the 75th maximum thrust take-off, the engine needs to be replaced.
Qantas operates the Trent 972 engine, which delivers a maximum thrust of 72,000 lb. The only other current two Trent 900 operators, Lufthansa and Singapore Airlines, operate the Trent 970 with a maximum 70,000 lb of thrust.
That extra 2,000 lb on each engine is needed to get the A380 off LAX’s relatively short runways in a headwind with a full load for a 14 hour flight in light of Airbus adding structural weight to the A380 in 2007. Prior to that time Qantas planned to use the 70,000 lb Trent 900 variant.
However, the extra thrust exposes the engine to 540 psi at P30, which causes the engine to experience “high severityâ€, the affidavit says. Rolls-Royce’s interim suggestion to Qantas has to been to derate the engines in order to “reduce the engine pressure ratio in the ‘P30′ area of the engine and therefore increase the life of the oil transfer tubes within the HP/IP support structureâ€
The oil transfer tubes are the suspected cause of an oil leak that started a fire and then the uncontained engine failure. The derated thrust, however, reduces payload and makes the LAX-Australia route unprofitable.
The Trent 900 has had three modification standards: A, B, and C. Qantas and Rolls have agreed the carrier should not operate at all the “A modâ€. The “B mod†and “C mod†can be used, even for maximum thrust–but only 75 times. After the 75th maximum thrust take-off, the engine needs to be replaced.
Sure the passengers would feel safer. 