SR-71A 17951, on display at Pima Air Museum in Tucson, AZ, is the matriarch of the SR fleet. She is the oldest surviving SR-71 with only one produced before her, 17950, which was lost to a fire on the runway. She first flew on March 5, 1965, and she served as a test bird for her whole career. With lots of test equipment and instrumentation aboard, she was too nonstandard for operational reconnaissance work.

She first flew as the contractor test aircraft based at Air Force Plant 42 in Palmdale, CA. Her role changed after the loss of two YF-12A NASA research aircraft. On July 16, 1971, she was loaned to NASA as the replacement. To conceal the fact that the USAF loaned an SR-71 to NASA, her designation was changed to “YF-12C 06-6937”. Her first flight with this new designation would take place on May 24, 1972, and she would serve as a NASA propulsion test vehicle until October 27, 1978, when she was transferred back to the USAF. At that point, she regained her original designation.

951 made her final flight on December 22, 1978, rolling up a total of 796.7 flight hours. She remained in storage at Plant 42 until 1990 when she was disassembled and transported by road to Pima Air Museum. After recent restoration, the aircraft stands proudly among one of the largest aerospace collections in the world. At Pima Air Museum, you can touch an original, classic blackbird.