Despite the troubles on board BX 411 and the provocative nature of US bomber flights under SCATHE JIGSAW, responsibility for the loss of BX 411 and all of its passengers rests squarely with North Korea. Why did North Korea mistake BX 411 for a SCATHE JIGSAW bomber mission, and why did the crew choose to shoot it down?
The answer may rest atop a high mountain, near the North Korean city of Sariwon. In 1987, the Soviet Union supplied the Democratic People’s Republic of Korea (DPRK) with two batteries of SA-5 Gammon long-range surface-to-air missiles (SAMs). Each of these batteries came equipped with a P14 TALL KING radar. It was these two radars—one atop the mountain near Sariwon and the other situated to the east, near Wonsan—that provided the primary means by which North Korea detected aircraft approaching its airspace. Communications intercepts made available by the Department of Defense indicate that it was the TALL KING radar that first saw BX 411 approaching North Korea.
The view from the TALL KING radar was limited. What the radar operators saw was a blip on a screen—in this case, an aircraft flying without a transponder and traveling along a path that resembled that of a previous bomber flight.
Communications intercepts show that the TALL KING radar near Sariwon detected BX 411 just as the electrical problems began. At around 11:50 AM, the commander of the SA-5 missile unit placed a call to the sector commander to report a strange apparition on the TALL KING screen.
SA-5 UNIT: Track 37, unknown.
SA-5 UNIT: Bearing 3-3-0, north.
SECTOR COMMANDER: Can you identify it?
SA-5 UNIT: Transponder off. Looks like another American bomber.
SECTOR COMMANDER: Okay. I’ll send it up.
The detection was noted and passed up the chain of command. Communications intercepts show that the sector commander promptly contacted the Korean People’s Army (KPA) Air and Anti-Air Force, headquartered in Chunghwa. For SCATHE JIGSAW flights, the protocol in place required the duty officer at Chunghwa to put the sector commander in direct communication with the commander of the Air Force. But at this moment, shortly before noon on March 21, the commander was not available, so one of his subordinates took the telephone call instead.
SECTOR COMMANDER: Tell the boss we have another one.
ANTI-AIR COMMAND: He’s asleep.
SECTOR COMMANDER: It’s the morning. You might want to wake him up.
ANTI-AIR COMMAND: He had… a meeting. It went late. He took a pill.
SECTOR COMMANDER: Okay.
ANTI-AIR COMMAND: Don’t shoot unless it comes into our airspace.
SECTOR COMMANDER: Okay, we’ll shoot if it comes in our airspace.
The order handed down to the SA-5 unit from Chunghwa reflected standing orders to shoot down foreign aircraft that entered DPRK without permission. In 1994, when a US helicopter strayed into DPRK airspace, the North Koreans shot it down. Until now, none of the US bomber missions had crossed this threshold—but clearly Kim’s air commanders were on alert for such an incursion.
As the aircraft turned westward, the SA-5 unit handed tracking of the target over to another missile unit, this one deployed near the city of Ongjin. The crew of this unit was inexperienced. They had been deployed with a brand-new system, which the North Koreans called the Pongae-5 surface-to-air missile. One member of the crew, Roh Pyong-ui, was captured as a POW and subsequently debriefed. “It was the first time we had seen such a target in real life,” Roh said. “It looked just like training.”
Within the US intelligence community, the Pongae-5 SAM was known as the KN-06. North Korea had begun development on it in 2009, but that effort was plagued with problems, as were the attempts to construct the missile’s accompanying radar and engagement software. When North Korea announced mass production of the KN-06 in May 2017—“to be deployed all over the country like forests”—North Korean state media openly referenced the “defects” that had slowed its development.
As a consequence of the delays in the missile system’s development, the KN-06 unit that now took over the tracking of BX 411 had only begun training with the new system in February 2020, just after the lunar new year. This training was cut short following the eleventh and penultimate SCATHE JIGSAW bomber flight on March 6, at which point military authorities rushed the KN-06 unit to Ongjin.
The deployment of the unit seems to have been part of a general repositioning of North Korean air defenses using a limited number of KN-06 batteries. Following the initiation of SCATHE JIGSAW, North Korea probably repositioned the units to prevent their locations from being compromised by air probes. A minority within the US intelligence community believed that North Korea was positioning KN-06 units to improve the chances of shooting down an American aircraft.
But in either case, the pressure on the inexperienced crew of the KN-06 unit near Ongjin explains why they behaved as they did in the crucial minutes that followed their acquisition of the unidentified target. The sector commander made contact with the unit, passing along identifying information about the target and reiterating the standing order to shoot down any American aircraft that crossed into North Korean airspace. Communications intercepts show that the call, by radio, was hurried and brief:
SECTOR COMMANDER: American bomber coming into your sector, heading 275 degrees.
KN-06 UNIT: Okay, shoot it?
SECTOR COMMANDER: If you see it cross, shoot it.
KN-06 UNIT: Okay, if we see it, we will shoot it.
SECTOR COMMANDER: If it crosses. Don’t lose it.
KN-06 UNIT: Okay. We won’t.
The original Korean transcript leaves some doubt about whether the KN-06 crew understood that the order was a reiteration of a standing order to shoot aircraft that entered DPRK airspace without permission, or whether the crew believed that it was being told by the sector commander that BX 411 had already violated North Korean airspace and should be shot down if an opportunity presented itself. What is certain is that the KN-06 had a FLAP LID tracking and engagement radar that provided little information to the missile’s operators about what they were targeting. Thus, the KN-06 crew continued operating under the assumption that Air Busan Flight 411 was a bomber—rather than a jetliner with a payload of schoolchildren.
Neither can there be any doubt about what happened next. The missile unit at Ongjin tracked BX 411 out over the Yellow Sea. At 12:28 AM, the unit fired two surface-to-air missiles at its target. The first missile struck the Airbus A320 near the tail section, tearing the fuselage in two and sending the aircraft into the sea.
It remains unclear why the KN-06 crew concluded that the BX 411 had crossed into North Korean airspace and then chose to down the aircraft. Roh Pyong-ui, in his interrogation, insisted both that the aircraft had violated North Korean airspace and that it was a military aircraft sent as a provocation by the Trump administration. “We received an order that an American bomber was violating our airspace,” Roh told his interrogator. “For us, that is everything. It means we need to shoot it down.” Roh was asked repeatedly whether his crew made the determination itself that the aircraft had crossed into North Korean airspace or whether he understood the sector commander to have made that judgment. Each time, without answering the question, Roh insisted that the aircraft had violated North Korean airspace.
Roh also insisted that the aircraft was an American bomber or another type of military aircraft, despite being shown evidence that the aircraft was a civilian airliner. “That means nothing,” he responded when interrogators told him the aircraft was a civilian Airbus 320. “It is easy to turn a civilian type of plane into one for military use. We did it all the time.”