SOLE SOURCE TO GOODRICH CORPORATION The 309th MXSS has a sole source requirement for the procurement of Cyclic Endurance Test Spindles for Power Take-Off (PTO) Shaft Cyclic Endurance Test Stand 53E19-... SOLE SOURCE TO GOODRICH CORPORATION The 309th MXSS has a sole source requirement for the procurement of Cyclic Endurance Test Spindles for Power Take-Off (PTO) Shaft Cyclic Endurance Test Stand 53E19-95B. Part Number Description Quantity U10100 New Custom Test Spindle 3 Each U10615 New Custom Test Spindle 2 Each UA2086 New Custom Test Spindle 1 Each