Aircraft

Customers prompt European manufacturer to consider growth version of twinjet

Airbus is studying a “-900X” growth version of the A350, with weight increases of up to 20t and power possibly from larger-diameter engines, to counter Boeing’s plan to launch a larger 787 derivative, the -10.

“Customers are shown Boeing’s proposed 787-10 stretch and we then get asked what we can do with the A350,” says the programme’s chief engineer, Dougie Hunter.

He says that the manufacturer is studying possible minimum-change developments that could have a maximum take-off weight up 20t beyond the 245t now offered on the A350-800 and -900. “We could achieve this with the existing gear using larger wheels and tyres without running into ACN [runway weight loading] problems,” he says.

The largest A350 model is now the 300-seat A350-900, which has a range of around 13,900km (7,500nm), and is powered by General Electric GEnx or Rolls-Royce Trent 1700 engines at their maximum thrust ratings of 75,000lb (334kN). While the proposed heavier aircraft could use these engines with a range penalty, Hunter says that more powerful engines with a larger fan diameter can be accommodated under the A350’s wing, due to its redesigned gear arrangement, to improve payload/range performance.

“Part of the driver behind the decision last year to raise the nose and eliminate the nosedown fuselage angle while on the ground [that is a characteristic of the A330/A340] was to allow us to fit larger diameter engines in the future if required,” says Hunter.

According to industry sources, the increased weight and higher-thrust engines could be used to create an extended range “A350-900X” or a larger capacity “A350-1000” model. GE is believed to be proposing a derivative of the A380’s Engine Alliance GP7200 powerplant for the growth A350, while R-R has indicated that it will develop the Trent to meet airframers’ thrust growth requirements.

Hunter confirms that the A350 programme has suffered slippage of “around three months” following the decision in January to install an A380-based flightdeck. “The ‘Milestone 5’ [M5] definition freeze has been pushed back from March to June, and this has had an impact on the whole schedule,” he says.

The knock-on effect is that entry into service (EIS) of the -800 is now set for the second half of 2010 rather than mid-year, while -900 deliveries will “probably” now start in 2011, having previously been due at the end of 2010.

Hunter is confident that the three-month “M5 slip will not be translated exactly to the EIS date because there are certain things we can do in the production process to reduce the impact”.

Hunter says that final assembly of the first A350 is due to start in Toulouse during the fourth quarter of 2008, with first flight following in mid-2009.

MAX KINGSLEY-JONES / TOULOUSE