Boeing said assembly of its 787 Dreamliner has returned to a "steady production rhythm," after being disrupted by a strike and parts problems, with this week's work joining pieces of the fifth flight-test aircraft.

Boeing said assembly of its 787 Dreamliner has returned to a “steady production rhythm,” after being disrupted by a strike and parts problems, with this week’s work joining pieces of the fifth flight-test aircraft.

Five of the six airplanes designated for flight test are now in varying stages of production, Boeing said Friday in a statement. There are 24 other planes being worked on around the world under Boeing’s new supply-chain manufacturing model.

The Dreamliner is about two years behind schedule because of parts shortages and defects, redesign work and problems with the suppliers who are building most of the plane and shipping sections to be joined at Boeing’s plant in Everett. The vendors hadn’t been finishing all the work they were supposed to before shipping their pieces, which caused delays as Boeing workers struggled with the “traveled work.”

“Sections are arriving in Everett at the completion levels committed by our partners and close to what is expected for mature production,” Jack Jones, the vice president in charge of final assembly and change incorporation, said in the statement. “The substantial progress made by our partners streamlines the assembly process, which is essential as we ramp up production.”

The fifth airplane is the first to have General Electric GEnx engines; the first four will be tested with Rolls-Royce Group engines. Customers can choose between both options.

Boeing’s most recent timeline, announced last month, calls for the Dreamliner to make its maiden flight next quarter and be delivered to the first customer in the first quarter of 2010, rather than May 2008 as originally planned. Work was also hurt by a two-month strike by machinists last year that idled factories.

Boeing now has 895 orders from 58 airlines after Russia’s S7 Group canceled its request this week for 15 Dreamliners.