The plane, numbered ZA006, ran its engines for the first time Wednesday in Everett. Now the plane will enter a series of ground tests before taking to the skies for the first time.
Why the final plane has taken so long to join the test fleet isnt clear. It is one of two of the six that is powered by General Electric engines. The four others are Rolls-Royce-powered.
When the aircraft finally joins the test group, Boeing plans to use it to test the 787s extended-range operations and its resistance to lightning and other electromagnetic interference.
Two more test aircraft apparently will join the test cadre this fall as Boeing raises the throttle on its flight-testing regimen to meet an already-postponed delivery date of the first quarter next year. Those two planes werent part of the original plan.

