Co announces it has completed installing reinforcements within the side-of-body section on the first 787 Dreamliner. The modification entails installing new fittings at 34 stringer locations within the joint where the wing is attached to the fuselage. Installations were completed yesterday. Boeing expects to complete the installations on the static test airframe and the second flight-test airplane in the coming days. "Completing this work is a significant step toward first flight. We continue to be pleased with the progress of the team and remain confident the first flight of the 787 Dreamliner will occur before the end of the year,"

For the life of me I can not understand the rationale in installing these mods in the flight test aircraft before the static test airframe. I am sure there is a good reason, anyone know why? Flying before static testing is almost 100% complete carries a lot of risk. I would think that installing the mods in the static aircraft would have been easier than the flight test aircraft and would have helped the learning curve. I assume these same mods will go into the fatigue test airframe also??

Boeing is installing it on ZA001 and ZA002 at the same time as ZA997 so when ZA997 passes the test, they can get ZA001 and ZA002 into the air soon after. Otherwise, first flight for both planes would have been pushed into Q1 2010. Also, ZY997 needed repairs to return it to the same condition as a "new" frame which delayed the installation of the fix.

Boeing has almost certainly been performing tests on the stringers. That they felt four of them needed additional work seems to be proof of that. So while they cannot have absolute confidence that the test will now work, they appear to have high enough confidence that it will.

And honestly, even if it still fails before 150%, if it lasts deeper into the test, it could still allow the planes to get into the air and start logging miles and returning data. Since ZA001, ZA002 and ZA003 are not going to customers, they can still provide relevant data eligible for the certification program on things like systems and avionics even if the structure is not 100% representative of the final design.

The A380 flew before the wing-break test was done and I believe the 777 did, as well. So as long as Boeing feels confident the first three test birds will be safe even with a "compromised" structure (from a certification requirement standpoint), then there is no reason not to send them up.

I'm not sure they need to replace the stringers on the fatigue frame, since it is likely performing cycles at a level below that where the pre-existing stringer design started to show failure. So in a regular lifetime of service, the original stringers would have been fine. It was only when stressed to levels beyond what the plane would ever be expected to encounter in it's service life did they start to give way.

Matt Cawby is reporting on his blog that Boeing performed two wing load tests on ZA997 (the static frame) yesterday evening.

Having some involvement in previous new airplane static tests including wings, it has taken days in the past to complete these tests, to review all the data and check instrumentation and control equipment at intermediate steps. Maybe these tests can be completed faster and successfully.

The Seattle Times is reporting that the fatigue frame aircraft has successfully completed both the design load and ultimate load tests with the new fix for the side-of-body join and ZA001 should fly this month.

Well with all the extra holes (perforations) in the side of body/wing joint, don't you expect the test rig to break when they run the wing beyond ultimate load? After all, nothing tears on the perforation line.