GUY NORRIS / SEATTLE
Modifying bulkhead to flat structure increases capacity and competitiveness with rival Airbus A321, says Boeing
Boeing is studying a radical flattened aft pressure bulkhead design for the 737-900X which could increase seating capacity and help launch the project by mid-2003.
The flat bulkhead would replace the bowl-shaped structure as part of a comprehensive redesign of the aft section 48. Switching to a flat or "square" bulkhead would add an extra fuselage frame of interior space in which to rearrange galley and lavatory fixtures to provide room for more seats in the cabin.
The baseline 737-900 is limited to 189 seats due to exit limit regulations as it has the same door layout as the -800, but the -900X is available with extra Type 1 doors aft of the wing to increase capacity. With the redesigned bulkhead, the aircraft can house up to six more seats than previously projected depending on pitch and lavatory location, says product marketing regional director Kenneth Hiebert.
Although maximum capacity would be 220 passengers, Boeing sees the real value of the redesign in the extra space for three more seats at a more comfortable 29-30in (740-760mm) pitch. "Seating goes up from 201 to 204 pitched at 30in. This really gets us into the Airbus A321 area. Before, the -900X had the range but not the seat mile costs and with this increase we'll be there [on costs]," says Hiebert.
The redesign study has "heated the -900X up again", says Hiebert, adding: "The expectation level is very high with this." Talks with potential -900X launch customers are ongoing. "We are in conversation with them not just for this, but for a variety of aircraft," Hiebert says. Assuming a launch in mid-2003, the -900X could begin flight testing in late 2004 and enter service in the third quarter of 2005. "It won't take a big order to make this happen," adds Hiebert.
Other features of the proposed derivative include a two-position tailskid for reduced take-off and landing speeds, and sealed leading- edge slats. Range with optional winglets increases to about 5,735km (3,100nm) due to a 1,970 litre (520USgal) auxiliary fuel tank and increased maximum take-off weight of 83,700kg. The aircraft also has reinforced landing-gear legs, wingbox and keel beam structure.
Source: Flight International
