Boeing has delayed the first flight of ZA006, the last test flight airplane and the 2nd with GEnx engines. Sources have told me that internal schedules show the airplane having its first flight on August 30th (delayed from July 13 and July 26). No reason of the delay was known at this time.
I'm not sure but the delay may have an impact on delivery of the first GEnx powered aircraft which is to happen early next year. Boeing may opt to have some tests that were to be flown on ZA006 to be tested on ZA005, the current GEnx 787 that is flying.
Boeing will start final assembly of the 25th 787 to be built on Monday. After a line move that will put ZA006 in the ATS Hangar, ZA176 to the paint hangar, and ZA101 in building 40-24; ZA230 which is destined for Air India with GEnx-1B engines will start final assembly on July 12th. A second 787 (ZA231) for Air India will follow about two weeks later on July 27th. Boeing will start final assembly on the 27th 787 in mid August after which there will be a resequencing of part deliveries in order to allow the production system to catch up with work. At this rate Boeing should have about 36 airplanes either assembled or in final assembly at Everett. There is supposed to be a slight increase in the production rate from 2/month to 2.5/month but I'm not sure if that is still to be implemented around August/September as planned.