Bombardier is aiming to build on the "better than brochure" CSeries performance disclosed at the Paris air show by delivering a further 4% gain in 2018 through a package of improvements currently in development.

The Canadian airframer revealed at the show that, thanks to lower airframe drag, the CSeries "beat brochure" in terms of fuel burn. This has resulted in a 350nm (648km) increase in range for the larger CS300 variant and a 250nm improvement for the CS100.

"Fuel burn is already 1% better than brochure, and there's more to come," says Robert Dewar, CSeries vice-president at Bombardier's commercial aircraft division. "We have the opportunities to increase by another 4% through a combination of the engine and the aerodynamic airframe side."

That upgrade package is still being planned, says Dewar, and Bombardier needs to complete a "mini-conceptual design phase" with suppliers before committing to the exact gains it will deliver.

The improvements will come "roughly half/half between the engine and the airframe – a little bit more on the aircraft side", he says.

"It's kinda normal things – aero clean-up, bigger winglets and some other performance improvements that we don't want to share."

The "objective" is for most or all the package to be retrofitable, adds Dewar. "It will be a big percentage."

With regards to the initial aircraft being ahead of targets, Dewar says the manufacturer originally took a conservative approach to its CSeries performance claims as "there was a lot of technology risk at the beginning of the programme". He points to its all-new design, carbonfibre wing and unproven PW1500G geared turbofan engines from Pratt & Whitney.

"It's a combination of structural performance we have lots of available fuel volume available in the wing – and lower drag," says Dewar. "The engine is on spec and the aircraft has around 1% lower drag."

Dewar declined to reveal the CSeries empty weight, but he describes the aircraft's weight as "good numbers".

He attributes the CS300's greater range gain to the fact that its development followed the CS100 "so there was some learning in there we could use".

Source: Cirium Dashboard