Bombardier has further refined the design of its CSeries aircraft, increasing payload by roughly 1,000lb (454kg) in response to customer requests, changing the wing to improve short-field performance, and implementing automatic, outward popping over-wing exit doors to comply with forthcoming rulemaking in Europe and the USA.
In the process of transitioning from what it calls the "joint conceptual definition phase" to the "joint definition phase" of the CSeries, Bombardier has made a number of tweaks to the aircraft. It expects to reach preliminary design freeze later this year and final design freeze in late 2010, says CSeries programme management director Benjamin Boehm.
Among the changes, he says: "Airlines asked for roughly 1,000 odd pounds of payload increase and both [the CS100 and CS300] have around that."
To accommodate the increase in payload, Bombardier added 500lb of operating empty weight (OEW), a figure first disclosed to ATI last week by Bombardier commercial aircraft president Gary Scott on the sidelines of the ISTAT conference.
"What the airlines wanted was an increase in the payload of the airplane, so you do need to increase structure to carry it," Boehm now explains.
For instance, the OEW of the 110-seat CS100 has risen from 73,000lb to 73,500lb.
The MZFW (maximum zero fuel weight) and MLW (maximum landing weight) of both the CS100 and CS300 have also been altered as a result.
Using the heavier-weight ER versions as examples, Boehm explains that the CS100ER's MZFW has risen to 105,600lb from 103,800lb, while the airliner's MLW has grown to 111,500lb from a prior 110,000lb.
On the CS300ER, the MZFW is now 115,700lb, up from 113,500lb, while the CS300ER's MLW is 122,000lb, up from 120,000lb.
Additionally, Bombardier "put a few changes into the wing, and that wing change is to get better performance out of places like London City", from which the CS100 will be able to operate, says Boehm.
The benefits also help operations "out of Bogota, Mexico City and Florence," which could be served by either the CS100 or CS300, he says.
In tandem with these changes, Bombardier has decided to offer automatic exit doors from the get-go. Safety regulators in Europe and the USA "are proposing that all new designs have automatic ones so we've just made that baseline on the airplane, kind of thinking ahead," says Boehm.
He also reveals that Bombardier is studying whether to offer electrochromic windows as an option for the CSeries. The electronically dimmable window technology is being used by Boeing for the 787 twinjet.
"Some airlines think that for maintenance purposes, 'keep it simple and just go with the [regular window] shade' but we are investigating making an optional one where we would put in those electrochromic [windows]," says Boehm, adding that a few carriers have enquired about it.
Last week the Canadian airframer announced a firm order from Lufthansa for 30 CSeries CS100 aircraft in 115-seat configuration. Deliveries begin in 2014.
Boehm notes that the firm is "in the phase where we're doing a lot of listening to potential customers". It will be announcing further suppliers "fairly shortly". The CSeries is scheduled to enter into service in the second half of 2013.