Captain Milburn G. Apt, a test pilot for the United States Air Force, achieved a groundbreaking milestone in aviation history by becoming the first person to exceed Mach 3 during a test flight of the Bell X-2 aircraft. The Bell X-2 was designed as a rocket-powered airplane to explore the challenges of flight at hypersonic speeds beyond what was previously possible. During the flight, which took place over the arid landscape of Southern California, Captain Apt reached an impressive speed of 3.196, which was approximately three times the speed of sound. This extraordinary achievement was part of a larger program aimed at understanding high-speed flight characteristics essential for the development of future military aircraft.

However, shortly after this extraordinary accomplishment, the X-2 began to experience severe control issues, ultimately leading to a catastrophic loss of control. Despite his extensive training and experience, Captain Apt was unable to regain control of the aircraft, and it subsequently crashed. Unfortunately, he did not survive the incident, marking a tragic end to a promising moment in aerospace testing. The loss of Captain Apt served as a sobering reminder of the inherent risks and challenges faced by test pilots during the era of experimental aviation.

The Bell X-2 program continued even after Apt's death, providing crucial aerodynamic data that influenced the design of supersonic and hypersonic aircraft in the years that followed. This data included information on the thermal stresses and stability challenges encountered at high speeds that would prove invaluable for future generations of aircraft designers.