Assembly of the fifth Boeing 787 Dreamliner began at the end of January, marking the first new unit to enter the company's plant in Everett, WA, since late last summer. "This airplane signifies our return to a steady production rhythm," said Jack Jones, Vice President of 787 Final Assembly and Change Incorporation. "Sections are arriving in Everett at the completion levels committed by our partners and close to what is expected for mature production. The substantial progress made by our [supplier] partners streamlines the assembly process, which is essential as we ramp up production." Production at Everett had slowed because workers there were forced to complete work that some suppliers were unable to do. A strike by the machinists union also slowed production. The fifth unit, which will be used for flight testing and is designated ZA005, is the first to be powered with General Electric GEnx engines. Five of the six airplanes designated for flight test are now in varying stages of production. Power was restored earlier this week to the first flight-test airplane, ZA001, and production testing has resumed as the airplane prepares for its first flight in the second quarter. Rolls-Royce engines are hung on ZA002, which is in the fourth and final production position in the factory. The third and fourth flight-test airplanes, ZA003 and ZA004, are in the third and second production positions, respectively. Fastener rework is done on ZA001, nearly complete on ZA002, and progressing well on the third and fourth airplanes, Jones said. "We have applied the resources necessary to complete all the outstanding work on these airplanes and keep the production line moving forward." Assemblies for the final flight-test airplane, ZA006, are in production at partner sites worldwide. In all, assemblies for 30 Dreamliners are in production at this time.