A tip separated from the remainder of a prototype blade on one of Zond Systems' Z-40 wind turbines in late November. The failure occurred because of erroneous fabrication, says the company. The manufacture of the prototype blades, on one of the new Z-40 turbines, was inconsistent with design drawings, states Zond. The blades were made by Scaled Composites of Mojave, California, and company president Burt Rutan says that by mistake the blade spar was made in two pieces instead of one. The improper spar joint did not hold up in numerous emergency stops caused by storm induced grid problems during 60 mph winds on SCE transmission lines. Zond's Amir Mikhail says the turbine had otherwise exceeded expectations. It is to be used in wind plants for America, Europe and Asia this year.