Quick tangent on the 71:
It was the 1980s. The USA would frequently fly over the Baltic Sea with its SR-71 Blackbird at very high altitudes and up to three times the speed of sound. Despite the fantastic performance of the aircraft, Swedish interceptors were able to get a lock-on with its weapon systems during several different occasions.
This was just one of many examples recovered from the now finished Viggen epoch. An epoch which started nearly 40 years ago and has served throughout the Cold War and into the new age of the modernized, flexible, and network-centric warfare based Armed Forces.
Pilot Per-Olof belongs to the exclusive group who have had a first-hand encounter with the Blackbird, high above the Baltic Sea near Swedish airspace.
It was fairly routine during the Cold War that Swedish pilots would have to intercept aircrafts belonging to other nations. Usually the individual fighters that were in incident-readiness would suddenly be given orders to identify unkown aircrafts, and would sometimes have to reject some from entering Swedish airspace.
In the beginning of the 1980s, Per-Olof was one of the first pilots to introduce the JA 37 Viggen to the Swedish Air Force at F 13 in Norrköping. That was also when he became a part of the exclusive group of pilots who, with the JA 37, managed to get a lock-on on the US Air Force's most advanced reconnaissance aircraft - the SR-71 Blackbird.
Higher than anything else
The SR-71 is one of the fastest aircrafts built and was used on reconaissance missions at extremely high altitudes, more than 20 000 meters (~ 65 620 ft). The top speed was also very impressive - Mach 3, three times the speed of sound which is about 3 600 km/h (~ 22 370 mph). Despite the high performance of the aircraft, Swedish interceptors managed to at several occasions 'meet' the Blackbird over the Baltic Sea and get radar-guided missiles to lock-on. It often happened with a very short notice for the pilots involved.
Per-Olof Eldh says the factors that helped them accomplish this feat was that the jet fighters were in maximum readiness and ready-to-go at the time along with the fact that some of the encounters occurred during regularly scheduled training passes. The latter was the case when he himself met the SR-71 for the first time. Per-Olof was participating in an air-defense exercise when the situation suddenly changed.
"The target came flying in south of Åland outside Södertörn when I was led to a direct attack in the forward sector at a target altitude of 21 500 meters."
It was by then already outside the opening of Bråviken and P-O Eldh locked his radar onto the target. He was being guided by ground control the whole time and says that the radar was engaging at its maximum range with the semi-active anti-radar Rb 71 Skyflash as his weapon of choice. The event sounds dramatic, but this is how P-O Eldh describes the event afterwards:
"It was routine for me, but I was at a very high altitude. The digital control data that was presented to me confirmed it was either one of two possible aircrafts - a Soviet MiG-25 or a SR-71. I looked at what was happening on the radar to see if there was any attempt at jamming, and then pursued the target."
He then had a look to see if he could get a visual on the Blackbird.
"That was when I saw a graphite-grey aircraft pass me a few thousand meters above."
To this day he still does not want to reveal the exact altitude at which he was at, but it was much higher than he had been earlier. The first thing P-O Eldh noticed was that the sky had suddenly become dark.
"From being blue just a few minutes earlier, it was now black. On my way down again, I could also clearly see the curvature of the earth."
The method Per Olof Eldh used to reach the neccessary altitude was this:
"Let's assume my altitude was 8 000 m so I would be able to accelerate to Mach 1.35. I would then raise the nose about 3-5 degrees and continue accelerating during the ascent."
Fast-paced situations
P-O Eldh remembers how the SR-71 pilots liked to fly near or touching the border. In the beginning, they usually flew at Mach 3 when they came from the east, south from Åland heading towards Stockholm. Later on they would slow down to Mach 2.54 to get a better turning radius, and then hit full throttle between Öland and Gotland.
He encountered the SR-71 five times during his career. One of those events occured January 9th, 1986. Together with two colleagues, they took off from Bråvalla for a routine exercise. But before they even got the landing gear up they recieved new instructions and the group was assigned a course heading for Öland with the intent to carry through a so called "high-energy intercept" against the Blackbird.
"We climbed to 8 000 meters, turned around and accelerated over the Gotska Sea towards the Stockholm area and made contact with the target. Everything happened so fast, you're met with a relative speed of Mach 5. The mission only took 9 minutes."
The whole thing went fine for two of the pilots, but the aircraft of the third pilot suffered a high-temperature stall because of the high altitude and was forced to take emergency measures in order to re-start it.
"To fly the way you had to at an altitude of 16 000 meters involved very high risks."
Professionalism
General Lennart Petterson is the chief of the Tactical Flight Command but also he was a fighter pilot back in the days. He clearly remembers how fast everything went which missions against the SR-71 involved and describes these events as the highlights of his career.
"Each time was just as exciting and interesting. Intercepting the aircraft was tremendously difficult because of the high speeds and altitudes but it was one of the most extreme missions you could be a part of. When we succeeded, which we did most of the time, and afterwards could conclude that we actually would be able to shoot the SR-71 down if it were a live mission, it was quite pleasing since it was at the same time an evaluation of our professionalism."
Full story in the Swedish military official mag here.
