The first 777x Reg N779XW is expected to make the first test flight as soon as late June, and enter service with Lufthansa in 2020, which has 20 on order
The first two 777X flight test aircraft have left Boeing’s Seattle factory and are in integrated system testing on the ground, while the next two flight test airplanes are in final assembly.
The Boeing 777X is biggest aircraft being built by Boeing since the 747 built over 50 years ago, having a Length of 229 feet (69.79 m) for -8 and 251 feet, 9 in (76.72 m) for -9.
777x’s Wingspan Extended: 235 feet, 5 in (72.75 m), and on the ground with wingtips folded: 212 feet, 8 in (64.82 m)
Boeing 777x comes in two variants;
Boeing 777X-8 – 350-375 passengers with a range of 8,690 nmi (16,090 km)
Boeing 777X-9 – 400-425 passengers with a range of 7,525 nmi (13,940 km)
Katie Baileys Twitter
777-9 INITIAL ENGINE RUN!! She’s ALIVE!!! N779XW had her first engine run today producing smoke - and excitement from those watching