Boeing is examining four major 747 freighter development options based on the Longer Range 747-400XF variant formally launched on 30 April with an order for five from International Lease Finance (ILFC).

A major element of the four-point study is possible development of new, 65,000lb-thrust (290kN) engines smaller than the General Electric/Pratt & Whitney GP7000 and Rolls-Royce Trent 600s offered on the abandoned 747X, but larger than the powerplants used on the 747-400.

"We're talking to the engine makers, and none of us have made any commitments so far," says vice president 747 programmes Walt Orlowski. The key differentiator of the proposed engine has a much larger 8:1 bypass ratio, aimed at reducing take-off noise. Three of the four study options could make use of the new engine, he adds.

Option one is an improved variant of the newly launched -400XF, which has the same 412,770kg (910,000lb) maximum take-off weight as the passenger Longer Range -400 ordered into production last year by Qantas.

Improvements under study include wing modifications such as the trailing-edge wedge, larger winglets or raked tips, improved flaps, acoustic treatments to engines and re-engining with the newer engine type.

Passenger versions, which are included in the four options, would be offered with a new upper lobe area to free main deck space.

Option two is an increased gross weight version up to 431t (Flight International, 1-7 May), revealed earlier this month. "In that case, we'd really have to go to the new engine," says Orlowski who adds the heavier variant would be the basis for possible simple stretch derivatives. These would have "forward and aft plugs and could possibly make sense in the freighter market", he adds.

Option three is a "between place" derivative that mixes and matches the options offered in study areas one and two.

The fourth option is a shopping list of potential retrofit items from the -400XF that could be introduced to the -400 fleet. "We're looking at all the things that could make sense from a retrofit perspective."

The timing of the higher gross weight option is heavily dependent on the engine situation, says Orlowski, who says the provisional entry-into-service target is as early as the first quarter of 2005. Major changes over the Longer Range-400F include a heavily revised main undercarriage that would require larger wheel wells, as well as additional structural strengthening of the fuselage and wing.

In addition to the five ILFC ordered aircraft, at least two of which will be leased by Air France, Boeing has also taken orders for a further two Longer Range -400Fs from an unannounced customer. With the six passenger Longer Range models for Qantas, this takes total orders for the new version to 13. Deliveries are expected from November next year.

Source: Flight International