Key point: But it won't be enough to stop the U.S. military.

On July 27, 2013, as a column of armored personnel carriers and tanks rumbled before the stand of Kim Jong-un to commemorate the end of a bloody war with the United States sixty years earlier, four small American-made MD 500E helicopters buzzed low overhead. You can see it occur at 3:13 in the this video. If you look closely, you can see they have been wired with antitank missiles on racks slung on the sides.

In fact, this was the first confirmation that Pyongyang has maintained the fleet of 87 U.S.-built helicopters it smuggled into the country more than a quarter century ago.

The MD 500 is a civilian version of the distinctive Army OH-6 Cayuse light observation helicopter, which entered U.S. military service back in the 1960s. The no-frills design has been nicknamed the “Flying Egg” due to its compact, ovoid fuselage. It was widely employed to evacuate casualties, escort friendly transport helicopters, scout for enemy forces up close, and provide light fire support to troops on the ground with miniguns and rocket pods. Exceptionally cheap—selling for $20,000 each in 1962!—they were agile and small enough to land in places other helicopters couldn’t.

However, they were also highly exposed to enemy fire: 842 of the initial 1,400 OH-6As were lost in action in Vietnam. Evolved MH-6 and AH-6 “Little Bird” special operations and mini gunship variants continue to see action with the U.S. military today in Africa and the Middle East.

Back in the 1980s, McDonnell Douglas received an order for 102 helicopters from the Delta-Avia Fluggerate, an export firm registered in West Germany under businessman Kurt Behrens. Between 1983 and 1985, the U.S. company Associated Industries transferred eighty-six MD 500D and -E helicopters and one Hughes 300 (an even smaller two-man type) via six shipments for export by Delta Avia to Japan, Nigeria, Portugal and Spain.

However, in February 1985, the U.S. Commerce Department revealed it had discovered some hair-raising anomalies in the company’s operations—and some fraudulent claims about the shipments’ destination. For example, fifteen helicopters unloaded at Rotterdam, ostensibly for special fitting, were then transported overland to the Soviet freighter Prorokov. The Prorokov then unloaded the helicopters in North Korea. Similarly, a freighter docked in Japan transferred two helicopters to a North Korean freighter in Hong Kong, with similar results. Furthermore, it turned out the Semler brothers running Associated Industries were secretly majority owners of Delta Avia.

Though eighty-seven helicopters had already been delivered, the remaining fifteen MD 500s were seized and the Semlers were tried in 1987 for violating a law forbidding export of nearly anything to North Korea. It was alleged that Fluggeratte was simply a front company to ship the aircraft to North Korea, and that it had been promised a profit of $10 million for completing the deal. It was also revealed that a London insurer was in the know, and that payments had been laundered through Swiss bank accounts.

McDonnell Douglas had been duped into shipping nearly a hundred scout helicopters to a country that still considered itself at war with the United States. However, the Semler brothers were let off with light sentences in exchange for guilty pleas, claiming they had been misled by Behrens as to the destination of the helicopters. They paid fines far below the value of the money they had received for shipping the helicopters. Behrens rather dubiously claimed the MD 500s did not fall under the export ban because they were not military types.

Later it was revealed that the CIA had been aware of the smuggling operation. It had been administered by a North Korean attaché in Berlin, and facilitated by a Soviet front trucking company in West Germany. However, the intelligence agency declined to inform civil authorities, because it didn’t want to reveal it had bugged the embassy.

Still, why would North Korea even want MD 500s? The civilian models certainly didn’t possess any advanced technology or specialized military gear that the North Korea or the Soviet Union would have been dying to get a hold of.

However, many countries would acquire both military and civilian MD 500s legitimately, due to their very low cost, and adapt them into military roles with gun pods and rockets. And it so happens that one of those countries was South Korea: Korean Air had delivered more than 270 MD 500s under a license for the Republic of Korea Army and Air Force.

Thus, it seems that North Korea likely acquired the MD 500s so it could use them to infiltrate across the demilitarized zone with South Korean markings, conducting surprise raids and inserting spies and saboteurs. North Korea maintains more than two hundred thousand commandos in its Special Operations Forces, more than any other country in the world. In the event of a conflict with its southern neighbor, Pyongyang would deploy thousands of operatives behind South Korean lines via tunnels, submarines, stealthy motor boats and helicopters to disrupt communication and supply lines and spread panic. Indeed, upon learning of the MD 500 caper, South Korean president Chun Doo-hwan angrily upbraided Washington for inadvertently making infiltration easier.

Pyongyang kept its substantial MD 500 fleet under wraps for decades, though a North Korean colonel admitted to the purchase in a 1996 interview with Der Spiegel. Keeping the aircraft functioning and supplied with spare parts would have posed quite a challenge. After the unveiling in 2013, a quartet of the American-built helicopters was again on display at the 2016 Wonsan air show, one of the choppers performing stunts for the audience.

The MD 500s seen over Pyongyang were modified to carry four Susong-Po antitank missiles. These are locally produced derivatives of the Russian Malyutka-P (NATO codename AT-3 Sagger-C), an older missile semiautomatically guided by the firer via a control wire. An earlier version of the AT-3 made a name for itself blowing up Israeli Patton tanks during the Yom Kippur War in 1973. This suggests North Korea envisions an attack role for the handy little choppers.

South Korea, for its part, may have its own plans for its large MD 500 fleet, which includes fifty antitank types armed with TOW missiles. Korean Air is proposing to transform these Little Birds into drone helicopters! This could be a handy way to employ the copters in a battle zone where their survivability rate might not be very high.

Pyongyang is not the only nation to attempt such shenanigans using shell companies. Iran famously acquired parts from the United States for its F-14 Tomcat fighters for decades. In 1992, shell companies established by the United Kingdom managed to purchase several T-80 tanks from Russia at a generous $5 million a piece, supposedly for service in Morocco. Instead, they were thoroughly taken apart and evaluated by the British, and then sent to the United States. More recently in 2015, U.S. citizen Alexander Brazhnikov was arrested after using shell companies in Ireland, Latvia, Panama and five other nations to smuggle $65 million in restricted electronics to the Russian defense ministry, nuclear-weapons program and intelligence services.

Still, none of these episodes quite match North Korea’s rare feat in shipping over eighty-seven factory-fresh helicopters from the United States.

Sébastien Roblin holds a master’s degree in conflict resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring.​ This first appeared last year.

Image: Reuters.