Boeing is preparing to reactivate the first 787 test aircraft for its long-delayed first flight later this month now that it has completed validation work on the modification to strengthen the side-of-body wing-fuselage join.

Within hours of the announcement that static tests were finished late on Nov. 30, the initial aircraft (ZA001) was rolled back out to the Everett flight line. Flight test engineers appear to be wasting no time in getting ready to resume pre-flight work and plan to conduct several engine runs, including thrust reverser tests later this week.

Work on the modification, which was required to beef up the wing join after tests earlier this year revealed weakness in the stringer caps, added a further six-month delay to the stalled development program. At the time of the new delay in June, the program was already running approximately 22 months behind schedule. However, Boeing says the '2C' loads verification tests on the static test airframe (ZY977), appears to have been positive and therefore sets the clock ticking toward the long-delayed first flight. The company expects "a full analysis of the test results to be concluded in approximately 10 days," but cautions that meeting the end of the month planned flight target depends on "a successful test result." Commenting in his blog, Boeing Commercial Marketing VP Randy Tinseth added, "The airplane did go to limit load as intended, but we're not going to characterize the results in any way until the analysis is complete."

The test subjected the 787 airframe, the wing and trailing edges to its limit load--the highest loads expected to be seen in service. "The load is about the same as 2.5 times the force of gravity for the wing," adds Boeing. The test verified the structural reinforcements made to the side-of-body section where new fittings were added at 34 stringer cap locations within the joint where the wing is attached to the fuselage. The modifications have been completed on the first two flight-test aircraft (ZA001 and ZA002,) as well as the full-scale static test aircraft (ZY997). Boeing plans to test the 787 wing to its ultimate load of 150% in around three to four months time, but is only required to exceed the 100% mark to enable flight tests to proceed.

Photo credit: Liz Matzelle