Paul Lewis and Guy Norris/SEATTLE

GENERAL ELECTRIC and Pratt & Whitney have agreed to joint development of an engine to power Boeing's new-generation 747 models, the 747-500/600X. Meanwhile, Boeing is expecting to be complete definition of the new models by mid-year.

The surprise teaming of the engine manufacturers results from just six weeks of negotiations, covering the establishment of a 50:50 joint-venture company to develop and market the engine. The joint-venture company plans to develop a powerplant family covering the 320-374kN (72,000-84,000lb)-thrust range, with an entry-into-service target of 2000.

"We will be conducting a study over the next few weeks to define the optimal engine definition and work assignments," says a joint GE and P&W statement.

Management of the venture, will be held solely by the two companies although, additional global revenue-sharing participants will be considered. Rolls-Royce reacted by saying: "It's interesting that they feel they need to join forces to compete against us. It's a testament to the Trent, but it's a step-up in the level of competitiveness."

The UK manufacturer has denied rumours, that it rebutted GE efforts to forge a link on the new engine, before the US company turned to P&W.

The linking of the world's two largest aero-engine manufacturers follows Boeing's decision to rule out off-the-shelf Airbus A330-class engines and uprated existing 747-400 propulsion from all three manufacturers. Boeing has instead opted for either a new-build engine or derivatives of the 777 power plant. R-R is expected to offer an optimised version of the Trent 800, with modifications likely to the high-pressure system. Before the GE/P&W announcement, R-R was tipped to be leading the pack to power the new-generation aircraft.

Boeing will complete its definition of the ultra-long-range 747-500X and stretched -600X by the end of June, and expects to launch both planned versions simultaneously by the end of the year. Key to the launch will be development of new engines to meet Boeing's ambitious performance goals. These include a 10% lower operating cost than that of the current -400 model at high Mach cruise speeds, low noise and 777 reliability levels.

Boeing is re-assuring the 17 members of its 747-X airline advisory group that, despite the US engine teaming decision, it intends to offer an engine choice.

"GE and P&W have not asked for exclusivity and we have not offered it," says Boeing. In April, GE signed a temporary exclusivity agreement with Airbus recently to study a new 226kN engine for the yet-to-be-launched A340-600.

The emerging 747 new generation will have a maximum gross weight of more than 450,000kg and will require Stage 3-plus engines. The cost and operating economics of developing a GE90 derivative which would fit within the smaller volume of the inboard engine positions of the new aircraft, plus that of producing similarly sized PW4000 derivatives was instrumental in the teaming decision.

"Boeing has urged us to pursue the joint programme to meet requirements for a growth 747. Neither of us was prepared to make the enormous financial, personnel and technical investment required to develop an all-new engine in an uncertain environment," says the combined statement.

Both new 747 versions are expected to be launched at the same time by a combination of Asian and European carriers. The stretched -600X is tipped to be the lead variant, achieving certification and service entry first - possibly as early as 2001.

Definition studies of the aircraft continue to throw up differences within the manufacturer/airline advisory group - of which British Airways, Cathay Pacific, United Airlines and Singapore Airlines (SIA) form the core.

Boeing is believed to, be proposing to use fly-by-wire (FBW) controls for flaps only and conventional controls, for the ailerons, rudder and elevator. The airlines are pushing for the much wider use of FBW technology.

Source: Flight International