MONTREAL -- Years of planning will be put to the test Monday when Bombardier's CSeries commercial jet is set for takeoff on its first flight, nine months behind schedule.

With the final on-the-ground tests nearing completion as of Friday afternoon, the aerospace manufacturer has been waiting for the skies to clear at Mirabel airport, north of Montreal. Forecasts call for variably cloudy skies with 20 kilometre winds and 30 per cent chance of rain.

Stands have been set up for employees and some suppliers and customers to watch the milestone event, which will be webcast live at www.cseriesfirstflight.bombardier.com.

Bombardier (TSX:BBD.B) plans to broadcast a TV show, complete with panellists from the company, area universities and some parts suppliers.

The world's third-largest aircraft manufacturer has a lot riding on the 110- to 160-seat plane, says Karl Moore of McGill University's Desautels Faculty of Management.

"It's very critical for (Bombardier) aerospace... On the plane side this is a central part of their plans going forward," he said in an interview.

The US$3.5-billion CSeries program is expected to generate US$5 billion to US$8 billion in additional annual revenues and help to raise the company's share price.

The plane's two versions have attracted 177 firm orders from 10 customers, and total interest for 388 planes. Barring delays, deliveries of the CS100 are expected to begin in a year, while the larger CS300 will follow at the end of 2014.

Moore said the first flight is largely symbolic given the years of computer and on-ground testing the plane has undergone, but it starts the clock to a year of flight testing.

"At one level it's a non-event because it's going to work for sure. But I think it's the symbolism of it and it allows them to go through that phase, get the data they need to go into production."

Flight tests will try to confirm promised operating and fuel savings that are key to the aircraft's long-term success. Bombardier expects the partially composite aircraft will be 15 per cent less expensive to operate and burn 20 per cent less fuel than similar-sized planes currently in service.

The savings are partially attributable to it Pratt & Whitney engines. Bombardier has a little head start on its rivals, but the savings are less pronounced when compared with planned re-engined aircraft of its rivals.

Moore said the lack of recent CSeries orders is worrying, but the first flight will be a key milestone to giving customers greater confidence after earlier delays.

Walter Spracklin of RBC Capital Markets said he expects orders will ramp up in the first half of 2014 after flight data compiled over about three months confirms promised savings. The greatest potential for new business will come once the plane is in service, he added.

"Engine testing to date has been coming in better than expected and we see limited risk that the CSeries will not live up to performance claims," he wrote in a report, adding that company officials have confirmed that order inquiries are starting to pick up.

He sees Air Canada, a Chinese airline, Flydubai and Swiss Air as the top candidates to place orders. Spracklin said the CSeries is under serious consideration for at least 30 to 50 aircraft as part of Air Canada's search for up to 100 new narrow-body planes to replace its Embraer single-aisle aircraft.

Fadi Chamoun of BMO Capital Markets expects the CSeries will capture 30 per cent market share or about 2,100 deliveries over 20 years. Since its launch in July 2008, the CSeries has captured about 23 per cent of the 770 aircraft orders in this seat range.

"We believe that it will be challenging for the CSeries program to generate a home run-type return on capital for Bombardier given stiff competition and the sizable up-front investment," he wrote.

Embraer's new E2 family of jets, particularly the E195 will be a challenger to the CSeries, Chamoun added.

Airlines are reluctant to add a new aircraft type in their fleet, but the CSeries would become more attractive as it approaches entry into service and validates the industry-leading per seat costs, he noted. Bombardier has also been reluctant to sell many early planes at large discounts, arguing it only needs to produce 10 per month to generate a reasonable return on investment.