"We have signed a letter of intent for 10 firm C-Series orders -- three CS100s and seven CS300s," Bombardier spokeswoman Haley Dunne told AFP.

"There are also options for three more CS100s and seven more CS300s -- 10 additional aircraft."

The CS100 list price is $57.8 million and the CS300 list price is $66.6 million, the spokeswoman said -- putting the value of the firm orders at about $640 million. With the options, the total would rise to $1.28 billion.

The letter of intent includes "buying rights" for another 10 planes, she added.

Bombardier's C-Series aircraft are a new line of fuel-efficient medium-haul planes. The first flight is scheduled for the second half of 2012, with the CS100 jets expected to go into service by the end of 2013.

The CS300 planes would go into service by late 2014.

The CS100 has a passenger capacity of about 110, while the CS300 will have about 130 seats.

Bombardier shares closed up 0.79 percent Wednesday on the Toronto stock exchange, at CAN$5.10 (US$5.20).

Copyright AFP (Agence France-Presse), 2011