Lost at 16:50 hours at Barry M. Goldwater training range in Arizona. Captain David O'Malley ejected safely. It was suspected that it was a 4th Stage turbine failure from a manufacturing defect. All F-16's of this engine type were grounded as a result of this loss. A fault in the engine was found and remaining aircraft began flying once this part was replaced. Work was expected to be completed by March 2005. It is now required to inspect these fan blades periodically.