Not really. It was a always pi$$ poor plan, it was poorly executed, there was little or no element of supervision and then, and only then, when Mr Murphy decided to pay them all a visit, did the fatigue become a factor. When those superior flying skills were required to dig them out of a hole entirely of their own making, the PF had nothing left in reserve because of the fatigue. To blame it simply on fatigue overlooks the massive negligence involved in the planning and execution of the whole test flight regime.