An independent review of the HOG UP program at this point concluded that the data on which the wing upgrade relied could no longer be trusted. This independent review was presented in September 2003. Shortly thereafter, fatigue testing on a test wing failed prematurely and also mounting problems with wings failing in-service inspections at an increasing rate became apparent. The Air Force estimated that they would run out of wings by 2011. Of the plans explored, replacing the wings with new ones was the least expensive, with an initial cost of $741 million, and a total cost of $1.72 billion over the life of the program.