Military Aviation

Valkyrie Down: the unsolved mysteries behind XB-70 AV2 Crash

Possibly Joe Walker was looking for a B-58A approaching at higher altitude while his F-104N (N813NA) inexplicably moved slightly closer to the Valkyrie and then rose suddenly so that the left tip of its horizontal stabilizer touched the XB-70’s drooped wingtip.

Of the many futuristic military aircraft concepts created in the 1950s, the North American XB-70 still stands out as the most awe-inspiring. With its huge, white, partially-folding wing, its fuselage resembling a striking cobra and its extraordinary performance, the XB-70 was one of the foremost technological achievements of the 20th century.

A strategic bomber built to outrun any Soviet fighter jet, it could reach Mach 3 with a full nuclear payload — as fast as the legendary SR-71 but more than three times the size. However, the Valkyrie’s role as a nuclear bomber was limited after the introduction of ICBMs, and defense cuts eventually led to the hugely expensive project being scrapped in the mid-1960s.

When the XB-70s completed their Phase 1 (manufacturer’s) stage of the test program in June 1966 they had already participated in the National Sonic Boom Program (NSBP). A range of supersonic aircraft laid booms over the Edwards area where NASA and USAF ground sensors recorded and analyzed the effects. Phase 2, also a USAF/NASA initiative, was more specifically targeted at SST research, for which a Mach 3 aircraft’s input was particularly relevant. Additional NASA instrumentation was installed in AV2.

As explained by Peter E. Davies in his book North American XB-70 Valkyrie, with NASA’s increased input came a new NASA pilot, Joe Walker, fresh from the X-15 program. For the USAF, Maj Carl Cross (aged 40, with recent Vietnam experience) was enrolled and they began to replace the original Valkyrie flyers, Al White and Joe Cotton. Both men put in training time on the TB-58A and many hours in the simulator to prepare them for XB-70 flights in June. Tragically, Maj Cross’s familiarization flight in AV2 was to be his last.

Their Jun. 8 flight (call-sign 207) was to be the first of two for AV2 that day, and the objectives included airspeed calibration and the second NSBP sonic boom run. It was an undemanding mission but ideal as an introduction for Cross. Al White took off at 0715hrs and completed the set tasks by 0830hrs. There was then an additional photo-shoot run, requested by General Electric to publicize five aircraft powered by its engines. Clay Lacy’s General Electric-powered Learjet photo aircraft was on hand for a formation led by AV2, flanked on the left by Cdr Jerome Skyrud and E. J. Black in a NAS Point Mugu-based US Navy F-4B Phantom II and a T-38A Talon flown by Capt Peter Hoag, with Joe Cotton in the rear seat. Off the Valkyrie’s right wing was a NASA F-104N Starfighter with Joe Walker aboard and a YF-5A piloted by John Fritz.

The group maintained a racetrack pattern at 25,000ft through some cumulus cloud for 30 minutes at 300mph. It was a chance for Maj Cross to fly one lap to experience the XB-70’s controls. The formation had to close in several times to suit the cameramen and hold position for another 15 minutes when a USAF F-104D photo aircraft also joined in. On the final circuit, three minutes before the Learjet was due to leave, the crews were informed of a B-58A approaching at higher altitude and all the pilots except Walker reported that they had spotted it. Possibly Walker was looking for it while his F-104N (N813NA) inexplicably moved slightly closer to the Valkyrie and then rose suddenly so that the left tip of its horizontal stabilizer touched the XB-70’s drooped wingtip.

The Starfighter was probably further destabilized as it entered the XB-70’s wingtip vortex. Inverted, it passed across the XB-70’s rear fuselage, taking off the right vertical stabilizer and the majority of the left one, before bursting into flames with the loss of one of the world’s most skilful and experienced test pilots. The fighter was cut in half behind the cockpit by the Valkyrie’s vertical stabilizer and the forward section then smashed into the left wing, causing severe damage to the upper surface. In a few seconds White worked out that the calls of “mid-air, mid-air!” that he was hearing actually applied to the far-away rear end of his own aircraft since no-one had told him directly what had happened. Cotton in the T-38A, referred to “two verticals … came off, left and right” and White knew theirs was the only twin-tailed aircraft in the pack.

The stricken Valkyrie continued to fly normally for 16 seconds and then began a slight rolling motion. White tried to correct it, but without vertical stabilizers this increased the instability and the huge aircraft started a snap roll to the right and then entered an uncontrollable, inverted right-hand spiral descent, spilling fuel from its damaged wing. Cotton saw a large section of the left wing break away as AV2 entered a flat spin.

White encapsulated, but his right arm got trapped between the upper capsule door and the bailout handle as the doors closed. To eject at that point would have cut off his projecting elbow on the hatch frame above his head. With the doors partly open his intercom was inoperative so that he could not help Cross or talk to him, although he could “see his helmet, bobbing around. There was nothing I could do to help Carl.” Possibly he was injured and rendered unconscious during the initial, unexpected snap roll. Cross’s seat was not retracted into his capsule. Ballistic (automatic) encapsulation was triggered but the forward forces acting on the spinning Valkyrie were too great for the seat retractor to pull the scat back and begin the ejection system. It had blown its relief valve due to the excessive load.

Al White managed to release his arm after an agonizing 80 seconds of effort and he ejected with the capsule doors still partly open. The parachute deployed immediately, tipping him forward in his scat, and he watched the tumbling wreckage of his aircraft pass close beneath him as it fell at about the same rate. He closed the capsule door fully to shut out his vertiginous situation and tried to inflate his attenuator bag beneath the capsule. It had not deployed because the doors were partly open on ejection, covering the bag, and White could not locate the manual back-up lever.

About two minutes after the original collision the XB-70 hit the ground near Barstow, California, with an impact that White could clearly hear. His capsule drifted away from the blazing pyre and it hit the ground with a considerable impact moments later so that his scat was partially torn from its mountings by the 44g force. His heels made indentations in the capsule floor. White extricated himself through an 18in gap in the capsule doors despite arm and back injuries, wrapped himself in his parachute to alleviate the coldness of his shocked state, and awaited rescue.

Don Mallick, who would later fly the XB-70 himself, had just returned from a weather check flight in F-104N NASA 812 when he noticed two columns of black smoke east of Edwards. When he was told the bad news he and flight surgeon Dr Jim Roman took off in a Bell 47G helicopter to investigate. As they reached the crash site they saw, “The once proud ship was lying on the ground as if it `pancaked’ in a spin. It was flattened into the desert, its formerly white surface charred gray and black. The majority of the fuel had burned off and the big black smoke columns were gone, replaced by thin streamers of white smoke. The stainless steel airframe was flattened and shattered. The six round engine nozzles were now oval-shaped, but it was surprising how much of the structure had survived the fire.” Test pilot George Marrett, circling the site in a radio-relay T-38A, saw that some parts were still burning intensely.

Mallick discovered that the remains of Carl Cross were still inside the wreck, but Al White was alive with severe injuries. Mallick and Dr Roman set off in search of the crashed F-104N and soon found another flattened, smoking wreck 22 miles away. “The center of it glowed white hot like burning magnesium.” Some distance away they discovered the nose section with Joe Walker’s body still strapped into his seat, and it was clear that he had been killed during the original mid-air collision. Leaving the rest of the recovery to a USAF team, they used their helicopter to chase off an illegally snooping Press helicopter and returned to Edwards, astonished that such a disaster could have befallen the Valkyrie and its escort.

Maj Cross’s capsule was too badly damaged to yield any definite conclusions regarding its lack of success, although it showed that he had pulled one of the ejection handles. The lack of an operable “hot mike” between the capsules prevented the investigators from finding out what he might have said to White, or any advice he might have otherwise received from the pilot, while trying to encapsulate. Possibly a conventional ejection seat would have worked better in the circumstances.

Mallick returned to the site several times to collect debris for the official inquiry board as its members pored over the many photographic images of the collision. Among the fragments they found was the crucial section of the F-104N’s tailplane. Examination revealed the imprint of the formation light on the XB-70’s wingtip. Calculations showed that within eight feet of the wingtip the power of the swirling air vortex it created would equal the effect of maximum roll control in the small-winged F-104N, making a collision inevitable. The reason for Walker’s hazardous proximity to the wingtip remained elusive and theories abounded, even in the official inquiry, including several that he was distracted by other aircraft near the formation or that he did not notice his fighter’s slight drift towards the Valkyrie. Possibly he was focusing on the Valkyrie’s fuselage to maintain formation and could not see the wingtip. The disaster became one in aviation history’s long catalog of unsolved mysteries.

There were inevitable recriminations about the wisdom of allowing such a close-formation publicity session, requested by John Fritz and approved by Joe Cotton and their immediate superiors, although permission from higher authority was not sought. Col Albert Cate, Cotton’s boss, was blamed and sacked and two other officers were reprimanded. The loss of AV2 and the pilots was clearly a terrible blow to the program. Apart from the financial loss (more than $230m for the two aircraft alone), the full burden of continued research had to be borne by AV1 until its final flight in February 1969.

The following video features the deadly photoshoot that caused the mid-air collision between the XB-70 AV2 and the F-104N (N813NA).

North American XB-70 Valkyrie is published by Osprey Publishing an is available to order here.

Photo credit: U.S. Air Force

Dario Leone

Dario Leone is an aviation, defense and military writer. He is the Founder and Editor of “The Aviation Geek Club” one of the world’s most read military aviation blogs. His writing has appeared in The National Interest and other news media. He has reported from Europe and flown Super Puma and Cougar helicopters with the Swiss Air Force.

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