In the 1960s, when a single military incident had the potential to spark a nuclear war, the US government needed a surveillance plane that absolutely could not be detected, intercepted, or shot down.

The answer was the SR-71.

The Lockheed Martin SR-71, or the "Blackbird" as it is commonly known, flew at the upper 1% of earth's atmosphere at altitudes of 80,000 feet and speeds of over 2,000 mph — much faster and higher than any plane before it.

And every inch of the aircraft was meticulously designed to baffle radar detection.

The SR-71 was a marvel of engineering that flew in the US Air Force for more than 30 years. The plane holds records for speed and distance that stand to this day. It was so fast that the plane's common protocol for avoiding missiles was to simply outrun them.

Former US Air Force Major Brian Shul describes his career as a pilot of iconic Blackbird in his book "Sled Driver." He describes one incident in particular that he would never forget — something that reveals just how intense and difficult piloting the SR-71 could be.

As a Blackbird pilot, Shul is often asked about the plane's top speed.

"Each SR-71 pilot had his own individual 'high' speed that he saw at some point on some mission," Shul explains in the book.

Because the planes are so precisely engineered, and so costly, no pilot ever wanted to push the Blackbird to its absolute operating limits of temperature and speed. But you could fall short of those limits and still be going astonishingly fast: "It was common to see 35 miles a minute," says Shul.

As far as his personal high speed goes, Shul says, "I saw mine over Libya when Ghaddafi fired two missiles my way, and max power was in order. Let's just say that the plane truly loved speed and effortlessly took us to Mach numbers we hadn't previously seen."

US Air Force Major Brian Shul pilots the SR-71. USAF/Brian Shul via Wikimedia Commons Tales of the Blackbird's speed and achievements in espionage are unsurpassed, but Shul's most amazing anecdote in "Sled Driver" is the story of his slowest-ever run, which started off as a simple flyby to show off for friendly troops. It ended up the stuff of military legend.

While returning from a mission over Europe, Shul received a call from his home base in Mildenhall, England, requesting that he do a flyby of a small RAF base. An air cadet commander in that base was himself a former Blackbird pilot. Knowing what a spectacular sight the plane could be, he thought that a low-altitude flyby might give his troops a morale boost.

The Blackbird made its way to the RAF base, ripping through the skies over Denmark in just three minutes, and slowing down only to refuel midair.

TSgt. Michael Haggerty, USAF Using the sophisticated navigation equipment aboard the Blackbird, Shul's navigator, Walter, led him toward the airfield. He slowed the lightning-fast ship to sub sonic speeds and began to search for the airfield, which like many World War II-era British airbases had only one tower and very little identifiable infrastructure around it.

As the two got close, they were having trouble finding the small airfield. Shul describes the moments leading up to the flyby: "We got a little lower, and I pulled the throttles back from 325 knots we were at. With the gear up, anything under 275 was just uncomfortable. Walt (the navigator) said we were practically over the field — yet there was nothing in my windscreen."

ExpertInfantry / Flickr As the airfield cadets assembled outside in anticipation of catching a glimpse of the Blackbird, Shul and his navigator eased off the accelerator and began circling the forest looking for any sign of the base.

During the search, the Blackbird's speed had fallen well below advisable or even safe levels.

"At this point we weren't really flying, but were falling in a slight bank," recalls Shul.

With the engines silent on the low-flying Blackbird, the cadets on the ground couldn't see or hear anything. There was simply no way they could have expected what would happen next: "As I noticed the airspeed indicator slide below 160 knots, my heart stopped and my adrenalin-filled left hand pushed two throttles full forward."

TopGunMilitary Shul describes what happened next as a "thunderous roar of flame ... a joyous feeling."

The cadets must have seen" 107 feet of fire-breathing titanium in their face as the plane leveled and accelerated, in full burner, on the tower side of the infield, closer than expected, maintaining what could only be described as some sort of ultimate knife-edge pass."

Shul and his navigator returned to base in silence. They were both shocked by the momentary lapse in speed that nearly saw their Blackbird plummeting towards the hard ground. They had come close to a full-on catastrophe — much too close for comfort.

The pair felt sure that their commander would have had a panic attack, and would be furiously waiting at base to ream the pilots and take their wings.

Instead, they were greeted by a smiling commander who told them that the RAF had reported "the greatest SR-71 fly-past he had ever seen."

The spectators had taken their near-fatal mistake as an especially brave and well-executed stunt carried out by erudite professionals. The commander heard about the "breathtaking" flyby, and heartily shook both Shul and Walter's hands.

The crew of a NASA Lockheed SR-71 Blackbird standing by the aircraft in their pressurized flight suits. NASA / Jim Ross via Wikimedia Commons Apparently, some of the cadets watching had their hats blown off from the extremely close passage of the Blackbird in full thrust. The cadets were shocked, but only the two pilots knew just how close a call the flyby had been.

As the pilots retired to the equipment room, they still looked at each other in a dazed silence. Finally, they broached the subject of the perilously low speeds.

"One hundred fifty-six knots (180 mph). What did you see?" The co-pilot Walter asked Shul, "One hundred fifty-two (175 mph)," he responded. These speeds are fast for a car, but in an aircraft designed to travel in excess of 2,000 mph, they are disturbingly slow and unsafe.

ExpertInfantry / Flickr A year later, as Shul and Walter ate in a mess hall, he overheard some officers talking about the incident, which by then had become exaggerated to the point where cadets were being knocked over and having their eyebrows singed from the Blackbird's raging thrusters.

When the younger officers noticed the patches on Shul's uniform, indicating that he flew the SR-71, they asked him to verify that the flyby had occurred. Shul replied, "It was probably just a routine low approach; they're pretty impressive in that plane."