Boeing will begin major assembly of the first 787-9 in the fourth quarter of this year, ahead of final assembly starting in Everett in early 2013.
The first flight of the stretched-body Dreamliner derivative is on course for the middle of next year, with first delivery to Air New Zealand scheduled for early 2014.
Speaking at the Singapore Airshow, Mark Jenks, Boeing's vice president of 787-9 development, said that the airframer had reached the 25% detail engineering release milestone early last week and is already producing components for the first aircraft.
"A quarter of the detail drawings have been released, this is a very big milestone in the programme. And we have a fairly quick ramp-up so that by the fourth quarter we are at about 90%," he said.
Assembly of major components for the first -9, like the centre wingbox, will begin in the fourth quarter and the rest will be completed in the first quarter of 2013.
"In that first quarter we will come to final assembly, complete build, and then [launch the] first flight in the middle of next year," said Jenks. "Delivery to Air New Zealand will be in early 2014."
Jenks said that lessons have been learnt from the troubled 787-8 production effort and Boeing aims to avoid repeating the problem of having a huge amount of travelled work between production stations.
"We will be very arduous about what travels, and making sure that the assemblies are complete or very, very near complete before they travel to the next station."
One new technology that is being incorporated into the 787-9 is hybrid laminar flow control (HLFC) on the tailplane and fin, which is designed to reduce drag. An HLFC surface was flight-tested on a 787-8 development aircraft, and Jenks says the design for the -9 is "essentially complete".