Operating lessor Lease Corporation International has emerged as the second firm customer for the Bombardier CSeries twin-jet, with a firm purchase agreement for 20 of the type.
LCI's deal including three CS100s and 17 CS300s, making it the first customer for the larger 149-seat version.
The deal also includes options on an additional 20 CSeries aircraft.
Bombardier's CS100 - launched by Lufthansa's order for 30 earlier this month - carries a $42.7 million list price while the CS300's is $49.9 million.
Irish-based LCI will take delivery of all three CS100 aircraft in the second quarter of 2014. The CS300 will be first handed over in the first quarter of 2015.
The CS300 delivery schedule will be quite aggressive as the operating lessor will take all 17 aircraft in 2015 and 2016.
"We feel there is a window of opportunity in this market as other manufacturers are not rushing with alternatives to their current products," LCI chief investment officer Tasos Michael tells ATI sister publication Commercial Aviation Online.
"We feel the transaction made a lot of sense in terms of timing, technology and opportunity in the cycle."
Lufthansa's commitment to the aircraft type has "greatly enhanced" the lessor's confidence in the product, he adds.
Commercial Aviation Online originally revealed in January that the lessor was preparing to sign for the CSeries.
LCI says the transaction has been complex, because the CSeries is a new aircraft family involving a new technology engine - the Pratt & Whitney PW1000G - and promising improved economics over currently-available products.
Bombardier claims the aircraft will be quieter, emit 20% less carbon dioxide and 50% less nitrogen oxides, and deliver dramatic energy savings - a 20% fuel-burn advantage as well as 15% improved cash operating costs, versus current in-production aircraft of similar size.
"It is a step forward in technology," says Michael. "We are confident about the testing of this programme and that it will be delivered in a timely manner."