Five years later, a second encounter between Su-15s and a Korean airliner would result in a heavier loss of life. That shootdown would become a flashpoint of the Cold War. And due to the mind-boggling navigational errors that led to the tragedy, it would spur US President Ronald Reagan to share the space-based radionavigation technology known as the Global Positioning System , or GPS for civilian use, notably as a location-spotting mechanism aboard commercial airliners.

In April 1978, the shootdown of Korean Air Lines Flight 902 by a Soviet Su-15 fighter plane killed two passengers and spared 107 others. The incident distressed the Soviet Air Defence Forces, not because it had shot down a civilian airliner, but rather that it had gotten so far into Soviet airspace before being intercepted.

Today, of course, you very likely have that technology in your pocket. Any of the navigation and ride-hailing apps on your smartphone, from Google Maps to Waze to Uber and Lyft, owes their existence in no small part to the over-zealousness of the Soviet air force. But prior to that, GPS had been in the hands of only US military.

However, heavy winds had disabled several ground-based defense radars in the region, and without full coverage the Soviet fighter planes could not locate the airliner. The MiG-23s returned to base, short on fuel. This was in part due to a policy of limiting the fuel load on standby aircraft after defector Victor Belenko flew his MiG-25 all the way to Japan in 1975.

Cold War tensions were at peak that year, and an American RC-135 reconnaissance plane had snooped just outside the Kamchatka airspace earlier that day. When Soviet radars detected the approaching jumbo jet, the Soviet Air Defenses Forces (PVO) scrambled four MiG-23 interceptors to deal with the interloper.

The crew was supposed to switch the computer to follow the gyroscope-based Inertial Navigation System , but for some reason it was not properly reset. Thus, when the plane missed the beacon, its autopilot remained fixed on a straight-line heading mode which led it hundreds of miles off course toward the Kamchatka peninsula, which served as a base for Russian nuclear forces.

On August 30, 1983, KAL Flight 007 departed from John F. Kennedy International Airport in New York City, bound for Seoul, South Korea, with 269 crew and passengers aboard. The 747 airliner made a refueling stop at Anchorage, Alaska, where the crew was informed that one of the radio navigation beacons the flight computer usually relied on was non-functional.

Declassified transcripts of the conversation between Gen. Valery Kamensky, commander of the Eastern District of the PVO, and his subordinate Anatoly Kornukov reveal that Kamensky was ready to shoot down the escaping airplane over international airspace—after confirming it was not a civilian plane. Kornukov, however, felt that the intruder was clearly a military spy plane, and advocated a shoot-first approach.

Thus, a jumbo jet flying at high altitude in a straight line, making no evasive maneuvers, managed to confound the Soviet air defense system and soar across the Kamchatka peninsula and back into international airspace. PVO commanders were hopping mad at the failure.

Unfortunately, Flight 007's straight-line path took it back over Soviet airspace as it overflew the Sakhalin islands. The PVO had a new wave of three Su-15s and one MiG-23 ready to catch the intruder. Radio communication transcripts reveal that around 6:12 UTC, the Soviet fighters entered visual contact with Flight 007 and began acquiring missile locks.

Years later, Soviet pilot Genadi Osipovich recalled seeing the 747's running lights and the row of lit windows along the passenger compartment. "I knew it was a civilian plane," Genadi admitted in an interview with Izvestia, "but it is easy to turn a civilian type of plane into one for military use."

The 707 airliner is indeed the basis for a number of American reconnaissance planes. However, there are no espionage variants of the 747, which has an iconic humped profile.