Lessons learned from the C-17A full scale airframe durability qualification test program

The qualification of the C-17A airframe structure with respect to durability requirements involved a number of full scale component tests and a virtually complete airframe test article. The full scale airframe durability article was tested for three design service lifetimes and an additional 28,000 full pressure cycles are being conducted. Then have been many lessons learned from this test program in the area of test spectrum development, instrumentation requirements, setting up an inspection program, tracking the accuracy of the loads applied and assessments of unanticipated fatigue cracking. This paper provides an overview of the test program and discusses the lessons learned in various aspects of the test program.