Within Defections
The Mi G 15 That Arrived After the War
A North Korean pilot's 1953 escape gave the United States a flyable MiG-15 after the Korean War had already ended.
On this page
- Why the United States wanted an intact Mi G 15
- How No Kum Sok landed at Kimpo
- What flight testing added beyond wreckage
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Introduction
On 21 September 1953, less than two months after the Korean War armistice, North Korean pilot No Kum-Sok landed a fully operational MiG-15bis at Kimpo Air Base near Seoul. The event became one of the most important technology defections of the early Cold War. For the United States, the value was not simply that a communist fighter had been acquired intact. The MiG-15 had been one of the most formidable aircraft encountered over Korea, and American analysts had spent years trying to obtain a flyable example. No’s aircraft provided exactly that opportunity: a combat-capable MiG that could be inspected, dismantled, and flown extensively under controlled conditions.[Air Force Museum]nationalmuseum.af.milAir Force Museum The Story of the Mi G-15bis on DisplayNo Kum-Sok of the North Korean Air Force, who had long before decided to escape to South Korea. Shortly after…Read more…
The significance of the case lies in what followed after the landing. Unlike wreckage recovered from crashes, No Kum-Sok’s MiG enabled systematic flight testing that revealed how the aircraft actually performed, where its strengths lay, and where its limitations appeared when compared directly with American fighters. The episode therefore became a classic example of how a single defection could accelerate the reverse engineering and technical exploitation of foreign military technology.[af.mil]nationalmuseum.af.milAir Force MuseumMikoyan-Gurevich MiG-15bisA defecting North Korean pilot flew the airplane on display to Kimpo Air Base in South Korea on…
Why the United States Wanted an Intact MiG-15
By the time No Kum-Sok defected, the MiG-15 had already earned a reputation as a dangerous opponent. Its appearance over Korea in late 1950 surprised United Nations air forces with a combination of speed, altitude performance, and heavy cannon armament. Although American pilots eventually achieved success against it with the F-86 Sabre, many questions remained about the aircraft’s true capabilities and design choices.[Wikipedia]WikipediaOperation MoolahOperation Moolah
The United States had therefore launched a psychological-operation effort known as Operation Moolah. Publicised in 1953, the programme offered substantial rewards and asylum to any communist pilot who delivered a serviceable MiG-15. The goal was not merely propaganda. American intelligence agencies and aircraft specialists wanted a complete aircraft that could be evaluated in detail rather than inferred from combat reports or damaged remains.[Wikipedia]WikipediaOperation MoolahOperation Moolah
Ironically, the operation achieved its technical objective only after the war had effectively ended. No Kum-Sok later stated that he had not known about the reward when he made his escape. His decision was driven by a long-standing desire to leave North Korea rather than by the American offer.[af.mil]nationalmuseum.af.milAir Force Museum The Story of the Mi G-15bis on DisplayNo Kum-Sok of the North Korean Air Force, who had long before decided to escape to South Korea. Shortly after…Read more…
How No Kum-Sok Landed at Kimpo
No Kum-Sok was a 21-year-old senior lieutenant in the North Korean Air Force who had flown combat missions during the war. On the morning of 21 September 1953, he departed Sunan Air Base near Pyongyang in a MiG-15bis and headed south. The flight lasted only minutes and reached high speed before he crossed into South Korean-controlled territory.[Wikipedia]WikipediaNo Kum-sokNo Kum-sok
Several circumstances made the escape unusually dramatic. American radar coverage near Kimpo was temporarily unavailable because of routine maintenance, meaning the approaching aircraft was not detected through the normal warning system. No also approached and landed in an unexpected direction, startling personnel on the ground. American pilots initially struggled to understand what they were seeing because a communist MiG was suddenly rolling onto an airfield normally occupied by F-86 Sabres.[Wikipedia]WikipediaNo Kum-sokNo Kum-sok
Accounts from the period describe the aircraft parking among American fighters while base personnel rushed to investigate. No exited the aircraft, surrendered, and was quickly taken for intelligence debriefing. His arrival instantly transformed a long-running intelligence requirement into a tangible asset sitting on the tarmac.[wikipedia.org]WikipediaNo Kum-sokNo Kum-sok
What Flight Testing Added Beyond Wreckage
The crucial contribution of No Kum-Sok’s defection was not merely acquisition but exploitation. Within a short time the MiG was transferred for technical examination. It was moved from Korea to Okinawa, where American test pilots, including Chuck Yeager and other experienced evaluators, conducted initial flights. The aircraft was later transported to the United States for a more extensive programme of testing and analysis.[af.mil]nationalmuseum.af.milAir Force Museum The Story of the Mi G-15bis on DisplayNo Kum-Sok of the North Korean Air Force, who had long before decided to escape to South Korea. Shortly after…Read more…
This process provided information that wreckage could never reveal. Engineers and pilots could:
- Measure actual performance across different flight regimes.
- Evaluate handling qualities and pilot workload.
- Examine maintenance practices and component accessibility.
- Compare the aircraft directly against American fighters.
- Verify or correct assumptions derived from combat experience.[af.mil]nationalmuseum.af.milAir Force MuseumMikoyan-Gurevich MiG-15bisA defecting North Korean pilot flew the airplane on display to Kimpo Air Base in South Korea on…
An intact aircraft also allowed analysts to understand how individual design features worked together as a complete system. Combat intelligence often produces fragmented conclusions based on sightings, gun-camera footage, and pilot reports. Flight testing converted those assumptions into measurable data.[Wikipedia]WikipediaOperation MoolahOperation Moolah
What the Tests Revealed
The MiG-15bis that No delivered represented an advanced version of the fighter. American evaluators found an aircraft that possessed genuine strengths but also important limitations. Testing confirmed why the MiG had been such a formidable adversary at high altitude. Its performance characteristics and powerful armament made it particularly dangerous in the type of air combat frequently encountered during the Korean War.[Air Force Museum]nationalmuseum.af.milAir Force MuseumMikoyan-Gurevich MiG-15bisA defecting North Korean pilot flew the airplane on display to Kimpo Air Base in South Korea on…
At the same time, direct evaluation exposed areas where American aircraft and tactics enjoyed advantages. Comparative testing against aircraft including the F-86 Sabre and other USAF types provided a more precise understanding of relative strengths and weaknesses than wartime encounters had allowed. Analysts were able to move from anecdotal pilot impressions to documented engineering and flight-test evidence.[Wikipedia]WikipediaOperation MoolahOperation Moolah
The aircraft continued to undergo evaluation after its transfer to Wright-Patterson Air Force Base and later Eglin Air Force Base. The testing programme extended well beyond the immediate aftermath of the defection, demonstrating how much intelligence value the United States believed remained in the aircraft.[Wikipedia]WikipediaOperation MoolahOperation Moolah
Why the Case Became a Model for Technology Defections
No Kum-Sok’s MiG-15 illustrates a recurring lesson in the history of reverse engineering foreign military technology: a working system is far more valuable than fragments. The United States had already encountered MiG-15s in combat and had access to various pieces of information about them. What it lacked was the ability to examine a complete aircraft under controlled conditions.[Wikipedia]WikipediaOperation MoolahOperation Moolah
The defection supplied three assets simultaneously: the aircraft itself, a trained operator, and an opportunity for prolonged technical exploitation. Because the MiG arrived after active fighting had ended, it could be tested methodically rather than under wartime pressure. The resulting knowledge helped transform the MiG-15 from an observed threat into a thoroughly studied system.[af.mil]nationalmuseum.af.milAir Force Museum The Story of the Mi G-15bis on DisplayNo Kum-Sok of the North Korean Air Force, who had long before decided to escape to South Korea. Shortly after…Read more…
For historians of military technology, that combination is what makes the episode notable. No Kum-Sok’s flight did not merely deliver a Soviet-designed fighter to American hands; it delivered the evidence needed to understand how that fighter actually worked, how it should be fought, and how its design compared with Western counterparts.[af.mil]nationalmuseum.af.milAir Force MuseumMikoyan-Gurevich MiG-15bisA defecting North Korean pilot flew the airplane on display to Kimpo Air Base in South Korea on…
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Endnotes
1.
Source: Wikipedia
Title: Operation Moolah
Link:https://en.wikipedia.org/wiki/Operation_Moolah
2.
Source: Wikipedia
Title: No Kum-sok
Link:https://en.wikipedia.org/wiki/No_Kum-sok
3.
Source: military.com
Title: The US Failed to Capture a Mi G-15
Link:https://www.military.com/daily-news/investigations-and-features/2026/02/23/us-spent-years-trying-capture-mig-15-then-north-korean-defector-delivered-one.html
Source snippet
Then a North Korean...25 Feb 2026 — The MiG-15bis reached Wright-Patterson Air Force Base in December 1953, was reassembled and remained...
Published: December 1953
4.
Source: nationalmuseum.af.mil
Title: Air Force Museum The Story of the Mi G-15bis on Display
Link:https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196377/the-story-of-the-mig-15bis-on-display/
Source snippet
No Kum-Sok of the North Korean Air Force, who had long before decided to escape to South Korea. Shortly after...Read more...
5.
Source: nationalmuseum.af.mil
Link:https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196115/mikoyan-gurevich-mig-15bis/
Source snippet
Air Force MuseumMikoyan-Gurevich MiG-15bisA defecting North Korean pilot flew the airplane on display to Kimpo Air Base in South Korea on...
6.
Source: awm.gov.au
Title: no kum sok defector
Link:https://www.awm.gov.au/articles/blog/no-kum-sok-defector
Source snippet
Australian War MemorialNo Kum Sok: Defector from the North21 Sept 2020 — The 21 year old pilot, Lieutenant No Kum Sok threw a photograph...
7.
Source: thisdayinaviation.com
Link:https://www.thisdayinaviation.com/tag/mikoyan-gurevich-mig-15/page/2/
Source snippet
This Day in AviationTag Archives: Mikoyan-Gurevich MiG 15A defecting North Korean pilot, Lieutenant No Kum-Sok, flew it to Kimpo on 21 Se...
8.
Source: thisdayinaviation.com
Title: mig 15
Link:https://www.thisdayinaviation.com/30-november-1951/mig-15/
Source snippet
30 Nov 2012 — A defecting North Korean pilot, Lieutenant No Kum-Sok, flew it to Kimpo, 21 September 1953. It was examined and test flown...
Published: September 1953
Additional References
9.
Source: reddit.com
Link:https://www.reddit.com/r/todayilearned/comments/qgyhcm/til_about_operation_moolah_which_offered_large/
Source snippet
Details about No Kum-sok and his defectionTIL about "Operation Moolah", which offered large cash rewards to North Korean pilots who defec...
10.
Source: facebook.com
Link:https://www.facebook.com/bodyforwife/posts/no-kum-sok-was-a-north-korean-fight-pilot-who-said-fuck-this-place-and-pointed-h/1547773910249093/
Source snippet
Kum-Sok defected, flying his Soviet-made MiG-15...TIL of No Kum-sok, a North Korean pilot who defected in his MiG-15, allowing the Wests...
11.
Source: facebook.com
Title: kenneth h roweborn no kum sok korean jan10 1932 rowe defected to south korea fly
Link:https://www.facebook.com/AFmuseum/videos/kenneth-h-roweborn-no-kum-sok-korean-jan10-1932-rowe-defected-to-south-korea-fly/1012191127010319/
Source snippet
Kenneth H. Rowe(born No Kum-sok; Korean Jan.10 1932)....A defecting North Korean pilot flew the airplane on display to Kimpo Air Base in...
12.
Source: facebook.com
Title: on the morning of sep 21 1953 no kum sok flew his mig 15 and defected from north
Link:https://www.facebook.com/AirZoo/posts/on-the-morning-of-sep-21-1953-no-kum-sok-flew-his-mig-15-and-defected-from-north/1201963478640444/
Source snippet
No Kum-sok defects from North Korea with Mig-15... Kum Sok, a North Korean pilot who defected on the 21st September 1953. For the intact...
Published: September 1953
13.
Source: theaviationgeekclub.com
Link:https://theaviationgeekclub.com/in-1953-this-north-korean-pilot-flew-its-mig-15-to-south-korea-and-chuck-yeager-flight-tested-it/
Source snippet
In 1953 this North Korean pilot flew its MiG-15 to South Korea. And Lt. No Kum-Sok's Mikoyan-Gurevich...Read more...
14.
Source: southernmuseumofflight.org
Link:https://southernmuseumofflight.org/the-mig-15-the-korean-war-and-no-kum-soks-flight-to-freedom/
Source snippet
The MiG-15, The Korean War, And No Kum-Sok's Flight To...On September 21, 1953, North Korean pilot No Kum-sok defected to the West by fl...
Published: September 21, 1953
15.
Source: commons.wikimedia.org
Title: File:MiG 15bis in hangar at Kimpo AB 21 Sept 1953.jpg
Link:https://commons.wikimedia.org/wiki/File%3AMiG-15bis_in_hangar_at_Kimpo_AB_21_Sept_1953.jpg
Source snippet
wikimedia.orgFile:MiG-15bis in hangar at Kimpo AB 21 Sept 1953.jpgWithin a day the plane was flown to Okinawa, today it is on display at...
16.
Source: reddit.com
Title: til in 1953 north korean air force lieutenant no
Link:https://www.reddit.com/r/todayilearned/comments/3iupri/til_in_1953_north_korean_air_force_lieutenant_no/
Source snippet
Kum-Sok...No's defection was considered an intelligence bonanza, and he was awarded the then exorbitant sum of $100,000 ($890,831 in 201...
17.
Source: lift.erau.edu
Link:https://lift.erau.edu/minutes-seeking-freedom-led-to-a-lifetime-in-aviation/
Source snippet
It was reassembled and more exhaustively flight tested. After...Read more...
18.
Source: psywarrior.com
Title: operation moolah the plot to steal a mig-15
Link:https://www.psywarrior.com/Moolah.html
Source snippet
defect and landed his MiG-19 at a South Korean airfield. Air Force... No Kum Sok as well as the historic events that transpired followin...
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