Andrew Doyle/MUNICH Guy Norris/LOS ANGELES
Boeing has launched market studies of a higher capacity, longer-range version of the 737-900 featuring additional passenger doors and more than 200 seats.
Known within Boeing as the737-900X, the aircraft is aimed primarily at countering the Airbus A321-200 in the European charter market.
Although at an early stage, the -900X studies could be completed as early as mid-year, according to 737 chief project engineer Michael Garrett. "There's always been a feel about whether we could increase the range and/or capacity of the aircraft relative to the passenger load, especially from tour operators. That hasn't gone very far until recently, and now there has been a lot more interest within Europe," says Garrett.
Boeing's primary focus is on increasing the passenger capacity of the -900 rather than the maximum take-off weight (MTOW), though the manufacturer is understood to be looking at introducing a stronger wing and undercarriage to give the -900X a greater range capability than the smaller -800.
The -900's exit limit of 189 would be overcome by adding a pair of Type I emergency exits aft of the wing, or by enlarging the existing forward doors.
"We'd like to limit the amount of work related to weight increase, because we have a family," says Garrett. "So any weight increase to get the range back would have to be looked at very closely. We wouldn't want to put pressure on the existing structure and engine."
The company aims to limit any increase in MTOW to 4,540kg (10,000lb), and says part of the product development study is aimed at establishing the size of the margin available without significantly affecting power and structural requirements. The proposed range of the -900X, with full payload, is in the 3,700-4,440km (2,000-2,400nm) bracket.
The basic 737-900 has a fuselage 2.6m (8.5ft) longer than the -800 but shares the same wing, engines and maximum take-off weight (MTOW), leaving it with around 400km less range. The larger aircraft also has the same number of passenger doors and exit hatches as the -800. This limits it to 189 seats under certification rules, making it unsuitable as a charter aircraft.
The 737-900's direct competitor, the A321, typically seats around 180 passengers in a scheduled layout, but has become popular with European charter airlines because it can accommodate up to 220 in a high-density arrangement.
Airbus plans to further improve the payload/range performance of its largest narrowbody with the launch of a 95t MTOW version - an increase of 2t.
Source: Flight International
