In a big boost for its CSeries program, Montreal’s Bombardier has signed a firm purchase order for 40 CS300 jetliners with global airline leasing firm Macquarie AirFinance.

Macquarie AirFinance, based in Ireland, leases aircraft to 73 operators in 43 countries and has optioned another 10 CS300s.

Bombardier stock ended the day up 3.7 per cent, to $3.63 on the news.

The company did not give terms of the agreement, but the cost is estimated at $3 billion.

Macquarie expects delivery of the planes from 2017 to 2019 and will lease them around the world. It currently has 136 jets, so the CS300 will become a significant part of its new fleet.

Macquarie’s bet on the CSeries is a significant boost for the jet, which has been plagued by development delays, including an engine fire which stopped test flights earlier this year.

But Bombardier announced test flights had resumed earlier this month, but there are still doubts it will meet its timeline for delivery late next year.

The CS300 is a wide-bodied jet with 100 to 150 seats and is 20 per cent more fuel-efficient than other commercial aircraft, Bombardier says. It is likely to be used on a range of routes from short-haul to longer transcontinental routes.

Including Macquarie’s order, Bombardier has booked orders and commitments for 563 CSeries aircraft, with firm orders for 243 CSeries airplanes.

Bombardier is also believed to be in talks with two Chinese airlines for more CSeries commitments.