Bombardier has stretched the larger version of its new CSeries airliner, the CS300, to offer a 160-seat high-density configuration in addition to boosting the capacity of the baseline aircraft by five seats to 135 passengers.

Existing CSeries order holder AirBaltic has been revealed as the one of the customers for the “extra-capacity” version of the CS300, with plans to configure its aircraft with 148 seats, says Mike Arcamone, president of Bombardier Commercial Aircraft.

To enable the higher-capacity options, design of the CS300 was modified to lengthen the fuselage, add an optional second pair of overwing exits and increase maximum takeoff gross weight, says Rob Dewar, VP of the CSeries integrated product team.

Arcamone and Dewar were talking at the unveiling of the almost-complete first CSeries flight-test vehicle, FTV-1, in Mirabel near Montreal this morning. The aircraft, the first of five CS100 flight-test aircraft, is scheduled to fly by the end of June.

Modification of the CS300 design, and its knock-on impact on the CS100 because of commonality, was partially responsible for development and assembly delays that forced Bombardier to push first flight back by six months from December, Dewar says.

Stretching the airframe has enabled Bombardier to increase seating capacity to 135 passengers at 32 in. seat pitch in the baseline version and to a maximum of 160 passengers with 28 in.-pitch “slimline” seats and the second pair of overwing exits.

For the first time in the industry, Dewar says, customers will be able to order the aircraft with the extra exits installed or retrofit them later to increase capacity. Structural provisions for the extra exits will be fitted as standard in all CS300 aircraft.

Increasing capacity to 160 passengers reduces cash operating cost by 8%, says Arcamone. “The 160-seat CSeries will have the same seat-mile cost as a 180-seat aircraft, so if the airline cannot fill a larger aircraft, it can still operate at the same cost advantage,” says Dewar.

Arcamone expects availability of the higher-capacity option to increase the market potential for the CSeries, now estimated at 7,000 aircraft over 20 years in the 100- to 149-seat segment.

“We have not quantified how many more customers it will bring, but it will definitely be more because we are offering another option,” he says

Despite having booked only 148 firm orders out of 382 commitments from 14 customers, Bombardier is confident of meeting its target of at least 300 firm orders from up to 20 customers worldwide by entry into service, now planned for mid-2014 for the initial CS100.

First flight of the CS300 is now scheduled for early 2014, says Dewar, leading to entry into service by the end of that year.

Following the delay and “reharmonization” of supplier delivery schedules, Dewar says the program is on track for a plan that requires delivery of one aircraft a month to support a 12-month flight-test effort leading to Transport Canada certification in mid-2014.

The cockpit for the fifth test aircraft, FTV-5, is being prepared for delivery from Bombardier’s St Laurent, Quebec, plant, and the fuselage barrel for FTV-4 already has been delivered to Mirabel by Shenyang, China-based supplier SAC Commercial Aircraft, says Dewar. Blamed for some of the program delays, SAC is now producing fuselage barrels at a rate of one a month, he says. “Component quality is excellent, and they are meeting their delivery schedule,” adds Arcamone.