Bombardier says that some of its CSeries suppliers have had “more challenges” than others delivering components on time for the new aircraft program, the manufacturer’s Commercial Aircraft President Mike Arcamone told reporters during a pre-Farnborough air show briefing.

“We are currently working with suppliers to find the challenges. We have put the right amount of resources to address that; we have mitigation plans in place,” added Arcamone.

But while Arcamone did not give a precise date for first flight, which has been scheduled for the end of 2012, he noted that in spite of the supplier issues “we want to fly into the new year.”

Arcamone also stressed that the more important milestones are first delivery of the CS100 by the end of 2013 and the larger CS300 by the end of 2014.

“We work margins every hour every day. We are working towards the milestones. With the information I have this morning we are on track,” he said.

According to Arcamone, major structures are in “advanced assembly” and “suppliers are making significant progress” and are “demonstrating that they are meeting our requirements.” He also noted that the key performance targets for the aircraft have been confirmed.

Bombardier has identified four areas to address ahead of first flight of its CS100, with Arcamone noting that the current focus is getting key structural components, supplier testing, systems maturity and in-house testing and simulations ready for the start of final assembly and production ramp-up.

Bombardier expects to have the first static test airframe ready by the end of September, followed by completion of the first flight test aircraft in December, with the major aircraft structures ready several months ahead of that. According to Bombardier, the CS100/CS300 still is on budget and the cash burn is within the previously defined limits.

The manufacturer plans to use five aircraft in the CS100 flight test program, plus another two for the CS300 version.