Rolls-Royce has offered operators of RB.211-524G/ H-powered Boeing 747-400s and 767s the option to retrofit their engines with the core of the Trent 700, in an effort to offset higher-than-expected fuel-consumption degradation and reliability problems in the existing power plants.
R-R recently accelerated development work on the so-called "hybrid", following encouraging results from initial tests. It is expected to provide a 2.5% reduction in fuel consumption and significantly improved reliability, compared with that of the -524G/H.
British Airways has yet to select an engine for 14 recently ordered 747-400s. The hybrid is being offered to power these aircraft. The retrofit option has been tabled partly because BA wants to maintain engine commonality across its 747-400 and 767 fleets. Despite this, BA is understood to have told R-R that the retrofit programme, which could cost over $2 million an engine, is too expensive.
Cathay Pacific is also discussing retrofitting its 21 747-400s with the Trent 700/-524 hybrid, although the issue of cost has not been resolved. Cathay is also insisting that R-R must demonstrate that its performance promises for the hybrid are achievable before the airline will commit to the retrofit programme, which would take two to three years to complete.
R-R confirms that it has "-been in discussion on this [retrofit] possibility with several operators".
The hybrid integrates the high-pressure (HP) core of the Trent 700, consisting of the HP compressor, combustor and turbine, with an otherwise standard -524G/H production engine. R-R has been under intense pressure from operators to solve problems with the -524's HP turbine blades, following several failures. These are gradually being replaced with single- crystal blades.
Source: Flight International
