Ca.1959: TOS USAF. Served as the testbed for the Pratt & Whitney TF-33 turbofan engines used on the B-52H. After the evaluation trials were complete it was restored to G configuration. By 4/89: Assigned to the 2nd Bombardment Wing, Barksdale AFB, LA. 29 Jul 92: Davis-Monthan AFB, AZ for storage.