Emirates´ commitment pushes the total number of new 787 orders and commitments this year to more than 180; and more than 210 orders and commitments for the 787-10 overall.
However, the order for the jets whose production helps support thousands of jobs at Airbus's United Kingdom plants has so failed to materialise.
The deal has been blocked by demands from Emirates - the biggest customer for the twin-deck jet, with 100 of them in service and a further 42 on order - that the pan-European plane-maker continues making the A380 for at least another decade.
Emirates Emirates' new Boeing 777 first class suite inspired by Mercedes-Benz.
Emirates' agreement includes conversion rights to switch the aircraft to 787-9s, offering the airline additional flexibility for its future fleet and global network. "Some of these will be replacements so that we maintain a young and efficient fleet, and others will power our future network growth". Aircraft deliveries will begin 2022.
The 787-10 Dreamliner is 5.5 meters (18 ft) longer than the 787-9 yet shares more than 95% commonality with its smaller sibling.