Following the U-2 spy plane came the development of the A-12 and SR-71 – for the CIA and USAF respectively.These aircraft would first see service over Vietnam, where their stealth tech and high performance capabilities would be pushed to their limits.
Decades ahead of its time, the SR71 blackbird was unparalleled in design. On the rare chance the aircraft could be picked up by enemy air defence, the blackbird’s high speed and altitude made it practically untouchable.
Over its long career, the aircraft was frequently tasked with flying deep behind enemy lines, collecting intelligence, and leaving without ever being detected. Many of its missions will likely remain classified for decades, but among its many areas of operation, the SR71 would take part in missions over Vietnam.
Following successful test and evaluation flights in 1962, several mach-3 capable reconnaissance aircraft were developed. These would be given the designation A-12, and were specifically intended for use by the CIA. In 1966, it had already been decided that the project would be halted by June 1968, giving way to the improved SR-71 Blackbird. Before this however, the A-12 would be deployed to Vietnam as part of a covert reconnaissance operation, marking its first mission in a war zone. These covert flights would become known as Black Shield, and then later on, as Giant Scale.
On the 31st of May 1967, CIA pilot Mel Vojvodich was tasked with flying an A-12 over north Vietnam and Laos, photographing suspected enemy rocket launch sites. Being based in Okinawa, the A-12 could operate over the south East Asian region with ease. Taking off from Japan, the aircraft flew into North Korean airspace at mach 3.1, at 80-thousand feet, taking photos of any possible enemy missile activity. It then crossed into Laos, then Thailand before circling back around. Crossing back over Laos and into Vietnam, the A-12 returned home after a mission spanning 3 hours 39 minutes.
By 1968, the A-12 had been decommissioned, and replaced by the SR-71 Blackbird which proved superior in every way. The A-12 required the pilot to fly directly over the target area, heightening risk. The SR-71 on the other hand could also choose to circle the target area from a great distance. Cameras and radar equipment on the sides of the airframe could look deep into enemy airspace without ever requiring overflight.
In February 1968, the military ordered Lockheed to destroy all equipment used to build the A-12, and send the aircraft into special storage hangers. Then, on March 21st 1968, the SR-71 would take part in its first reconnaissance mission over Vietnam, flown by Major Jerry O’Malley and captain Ed Payne. Flying over the demilitarised zone, the aircraft then headed towards Hanoi. Travelling at mach 3-point-1-7, at a height of 78-thousand feet, the aircraft was now over the most heavily defended airspace in the world, taking photos to help aid troops during the siege of Khe Sahn. Crossing over into Thailand, the aircraft refuelled by tanker, and then began heading for its base in Okinawa.
On approach to the base, the crew found that visibility was poor and foggy. Unable to find the runway, the crew took on more fuel by tanker, and was diverted to a backup strip in Taiwan. Another KC-one-thirty-five tanker took off, together the three aircraft headed in, with the SR71 flying between the two tankers. The blackbird crew identified themselves as a KC-one-thirty-five, and landed in between the two other aircraft. There, air traffic controllers and onlookers were puzzled by the strange looking aircraft which had identified itself as a tanker. Sitting on the tarmac in broad daylight for half an hour, space was eventually cleared in a hanger, and the SR-71 was hidden. It would remain there for two days until it could be safely flown back to Japan. Initially the two man crew had no change of clothes and had to go around dressed in their flight suits. Once clothes had been found for them, they still went to dinner wearing their ‘moon boots’.
One of the main limitations of the SR-71 was its turnaround time. Each flight was incredibly costly, requiring a large staff to be on station after each sortie, as high levels of maintenance were almost always necessary. As such, each sortie needed to be timed well, as once the aircraft had flown, it was likely to be in the hanger for a week. However, these limitations would soon be overcome by simply bringing more aircraft into operation.
From late 1968, SR-seventy-ones would begin operating more consistently over Laos, Cambodia, and Vietnam. By this time they were averaging one sortie per week, and as time went on, this average would increase. By 1970, two flights were scheduled per week, and by 1972, with large scale bombing operations underway, Blackbird pilots were averaging one sortie per day.
Oftentimes, pilots were tasked with double loops over Vietnam. To do this, they would set off from Japan, fuel up over the ocean, cross over North Vietnamese territory, then descend through Laos and into Thailand for refuelling. In a few instances, close calls forced pilots to retreat into Thai airspace, and in one case, an SR71 was forced to land at a royal Thai air base. After being refuelled by tanker, the blackbirds would then either cross back through Laos and then over Vietnam for a second pass, or divert if necessary.
After returning to base the film canisters from the Blackbirds would be unloaded, and then flown to Kodak headquarters in New York, where the photos were processed and sent to intelligence for analysis. After some time, commanders in Vietnam began to grow impatient with this process, and so a 24-7 development lab in Japan was chosen to process the film instead, dramatically speeding up the turnaround time – a necessity given the pace at which assets were being moved around on the battlefield.
Apart from reconnaissance, the blackbirds would also play a crucial role in the 1972 POW rescue known as Operation Thunderhead. Working with the CIA and Navy SEALs, who had snuck a small radio into a north Vietnamese POW camp, a complex escape operation had been devised. But before this plan could spring into action, the POWs needed a signal to begin. It was decided that this signal would be two sets of tri-sonic booms, exactly 15 seconds apart, which would be produced by two SR-seventy-ones flying at Mach-3. A third blackbird would also be on station should either of the first two have to abort. The mission was deemed successful by the pilots, however the few prisoners, who had the green light to escape, decided to cancel, fearing that the other POWs who were not in a position to escape would receive harsh punishment, as had often happened during prisoner escapes in Vietnam.
Despite its initial low radar profile during development, by the time of its large scale use in the Vietnam war, North Vietnamese Army troops were able to consistently track and lock-up these aircraft from the ground. In fact, it is noted that roughly 800 surface to air missiles were fired at SR-71 recon flights over Vietnam. Although none were confirmed to have hit a blackbird, in one incident a missile was reported to have passed within 150 meters of one aircraft. During operations, two blackbirds were lost due to mechanical failure; the first in 1970, and the second in 1972. In one unusual incident, a blackbird was almost hit by a small meteor during a night mission.
Blackbird missions were – according to pilot testimony – largely uneventful. At such high altitudes and speeds, most surface to air missiles would run out of fuel before reaching the aircraft. The crew were primarily concerned with monitoring the aircrafts autopilot and camera systems, as well as keeping course for refuelling and return.
Although uneventful, the reconnaissance flights these aircraft flew proved to be invaluable from an intelligence perspective. In many cases, North Vietnamese activity was exposed and tracked from the sky, giving allied forces on the ground strategic advantages.
The blackbird would go on to serve in other conflicts and operations over the following decades, yet its service in Vietnam – at the time the most heavily defended air space in the world – is a remarkable chapter in the history of stealth aircraft.