The last of a series of technical tests, including high-speed taxiing on an airport tarmac, are taking longer than expected, spokesman Marc Duchesne said Wednesday.
"The first customer is aware of the situation and is asking us to deliver a reliable aircraft," he said. Bombardier has not named its first CSeries customer.
It's the third delay for the much-anticipated aircraft, which is expected to compete with some of the smaller planes made by Boeing and Airbus.
"The industry is aware of the challenges that new aircraft from our competitors are providing with the operators. Basically, operators are telling us to make sure to deliver a reliable aircraft at entry into service, unlike some of our competitors' planes," Duchesne said.
Boeing's new 787, called the Dreamliner, was grounded for three months earlier this year due to concern about overheating lithium-ion batteries. Recent mechanical glitches on Boeing 787s caused three United Airlines flights to be cut short.
Airbus had to repair cracks on parts inside the wings of its huge A380 jets in 2011 and 2012.
Bombardier (TSX:BBD.B) had been aiming for the first test flight by the end of July after a June postponement, but now said it will occur "in the coming weeks" without giving a target date. The CSeries commercial jet offers a longer range, a longer cabin, a new engine and key components made of composite materials.
RBC Capital Markets analyst Walter Spracklin said questions about the CSeries readiness will likely be called into question. even though last month's delay didn't impact Bombardier (TSX:BBD.B) shares and the impact from the latest delay will likely be "muted."
"However, we are concerned that management credibility may be impacted with each subsequent delay and should additional issues crop up over the course of the CSeries program, the benefit that investors are willing to provide could diminish," Spracklin said in a research note.
"While a push of first flight by a few weeks is not material from a cost/development perspective, it will likely call into question the readiness of the CSeries avionics and fly-by-wire system — which has been the main area of concern for well over a year now."
Spracklin also said flight certification by Transport Canada is expected in the coming weeks but could be an obstacle.
Bombardier has received 388 commitments for two versions of the 110-to-160-seat aircraft, including 177 firm orders.
"We need a first successful flight, but also a successful flight test program leading us to the complete certification by Transport Canada," Duchesne said.
Duchesne said the plane engines were tested last week at Mirabel airport, near Montreal. Other tests include flying the aircraft on the ground in a simulated compartment as well as low-speed and high-speed taxiing. Bombardier also said it will take more time to validate the overall systems and software integration.
The CSeries is a critical new generation of planes for Bombardier Inc., which is Canada's largest aerospace company and the world's third-largest maker of passenger aircraft after Boeing and Airbus.
On the Toronto Stock Exchange, shares in Bombardier were down six cents to $5.01 in afternoon trading.
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