GUY NORRIS / LOS ANGELES AND MAX KINGSLEY-JONES / LONDON
Manufacturers set to choose from up to 30 alternative configurations to present to operators conference
Boeing is preparing a package of improvements for the 747-400 that will be unveiled at an operators conference later this year.
Almost 30 alternative configurations are being studied, ranging from noise and aerodynamic improvements to gross weight increases and a stretch, which are now being finalised after several months of talks with up to 20 operators. Boeing hints that new "engine treatments" and other sound suppression upgrades are emerging as the surprise priorities for the 747X product improvement plan (PIP).
The 747-400X studies emerged after Boeing decided to put its enlarged 747X stretch project on hold and concentrate on its sonic cruiser concept instead (Flight International, 1-8 May). The -400X upgrades are being proposed for passenger and freighter versions, models of which were displayed at last month's Paris air show.
A gross weight increase of the passenger version to 431t (950,000lb) is being studied which would increase range to 15,400km (8,300nm). The freighter and proposed simple stretch would be around 5t heavier. Other features being studied are an upgraded flightdeck and new interior based on that of the Boeing 777, and a "speed kit". The latter involves adding aerodynamic fairings in several locations including the nose and empennage area to raise average cruise speed to Mach 0.88.
The use of higher thrust engines is being considered along with wing aerodynamic improvements including a trailing edge wedge design and 767-400ER-style raked wingtips. Three class capacity could be increased to 424 passengers by utilising the 747X's upper lobe storage design for galley equipment to free up main deck space.
Sources close to Boeing's PIP planning efforts say of the numerous configurations offered to operators neither the high gross weight or speed kit options were in the top 10. The results of the study are due to be completed next month, though the full picture is not likely to emerge until Boeing briefs 747 users at an operators conference set for the third quarter.
The noise issue appears to be the first priority, "particularly amongst cargo operators" which want to ensure the aircraft can meet the stringent QC2 noise limits at London airports.
Engine treatment considerations are thought to include extensive nacelle and fan case rework studies, as well as possible re-engining itself. Airframe noise is also expected to be treated as part of the package. Boeing adds that, at this point, there is no decision on whether to offer the final results of the PIP study as a series of incremental upgrades, a gradual production line phase in with retrofit or as a comprehensive block change.
"We are currently discussing this aircraft with customers, but we don't have authority to offer," says Boeing vice-president marketing, Randy Baseler. He adds that if airline interest is strong enough and a launch decision is made in the next year, "Deliveries could begin three and a half years later. We could use this model as the platform for a stretch, either with the new wing designed for the 747X, or perhaps the existing wing if customers don't require as much range," says Baseler.
Source: Flight International
