787 approaches final gauntlet testing

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Before Boeing can undergo final high-speed taxi tests ahead of first flight, the 787 must pass two major milestones.

The first is a major series of tests for ZA001 - Boeing's first 787 test aircraft - that comes in the form of closed loop "Final Gauntlet" testing to evaluate ZA001's systems while fooling the aircraft in believing it is flying.

Final Gauntlet tests are scheduled to begin as early as 8 December and last -two to- three days. Boeing says its flight test preparations have the Final Gauntlet being completed ahead of taxi testing.

Programme sources say the Final Gauntlet will be split into two primary blocks. The first includes a B1 first flight profile, the standard checkout of all aircraft systems as part of standard production testing. The second block will be a more rigorous "first flight" final gauntlet with an expanded profile of tests and failure scenarios.

The second milestone, expected to come by 10 December, is a final validation of the side-of-body reinforcement designed to strengthen the upper stringers of the wing and centre wing box of the 787.

Boeing announced 23 June that the 787 was grounded to design a fix that would provide full structural margins to the aircraft's side-of-body structure. The company completed modification on 12 November.

The modification consisted of installing new fittings at 34 stringer locations within the joint where the wing meets the fuselage.

Boeing completed all pre-flight tests on the 787 static airframe on 30 November and said results would be analyzed within 10 days.

On 8 December, Boeing also plans to set up its Flight Emulation Test System (FETS), that interfaces directly with the aircraft and governs the gauntlet test.

The FETS system is part of a Boeing-patented method of "fooling" the aircraft's inertial and air data systems while in a simulated flying environment. This "stimuli", according to the original 1993 Boeing patent, causes aircraft systems to respond, allowing Boeing to demonstrate in-flight performance while remaining on the ground.

ZA001 recently completed an initial flight readiness review, followed by thrust reverser actuation, along with the central processor that monitors the aircraft's gross weight and center of gravity.

During the weekend, programme sources say ZA001 also completed electronic brake checks operated only on the main battery, along with hydraulic system leaks checks and regression testing of the latest flight control software build, version 8.0.2.

Boeing's first flight window remains slated for any time in December, but sources say that the company is targeting 15 December for the aircraft's maiden sortie.