Middle Eastern carrier Emirates has finalised its order for 150 Boeing 777X twin-engined aircraft, a deal originally disclosed at last year's Dubai air show.
The agreement comprises 115 of the 777-9X variant and 35 of the 777-8X, plus purchase rights on another 50. Deliveries will begin in 2020.
All of the jets will be powered by General Electric GE9X engines.
Boeing values the overall agreement at $56 billion at catalogue prices. This could rise to $75 billion if Emirates exercises all its options.
Emirates president Tim Clark says the agreement gives the Dubai-based carrier 208 777s on backlog. It already has 138 777s in its fleet.
"The 777X will offer us operational flexibility in terms of range, more passenger capacity and fuel efficiency," says Clark.
Boeing says design of the 777X is progressing, with production set to commence in 2017. The type has secured 300 orders and commitments from six customers.