On 8 June 1966, XB-70A #2 was in close formation with four other aircraft (an F-4, F-5, T-38, and F-104) for a photoshoot at the behest of General Electric, manufacturer of the engines of all five aircraft. With the photoshoot complete, the F-104 drifted into contact with the XB-70's right wing, flipped over, and rolling inverted, passed over the top of the Valkyrie, struck the vertical stabilizers and left wing and exploded, destroying the Valkyrie's rudders and damaging its left wing. With the loss of both rudders and damage to the wings, the Valkyrie entered an uncontrollable spin and crashed into the ground north of Barstow, California. NASA Chief Test Pilot Joe Walker (F-104 pilot) and Carl Cross (XB-70 co-pilot) were killed, while Al White (XB-70 pilot) ejected, sustaining serious injuries, including one arm being crushed as it was caught in the clamshell-like escape capsule as it closed around him just before ejection from the aircraft.
The USAF summary report of the accident investigation stated that, given the position of the F-104 relative to the XB-70, the F-104 pilot would not have been able to see the XB-70's wing, except by uncomfortably looking back over his left shoulder. The report concluded that Walker, piloting the F-104, likely maintained his position by looking at the fuselage of the XB-70, forward of his position. The report estimated that the F-104 was 70 ft (21 m) to the side of, and 10 ft (3 m) below, the fuselage of the XB-70. The report concluded that from that position, without appropriate sight cues, Walker was unable to properly perceive his motion relative to the Valkyrie, leading to his aircraft drifting into contact with the XB-70's wing. The accident investigation also pointed to the wake vortex off the XB-70's wingtips as the reason for the F-104's sudden roll over and into the bomber.