The status of many claimed aces in the Korean War has been increasingly debated as more data becomes available, showing that instances of over-claiming abounded on both sides. An example of this occurred on 20 May 1951, when the war's largest fighter battle to date took place between 28 F-86 Sabres and 30 MiG-15s. After this battle the Americans claimed three MiGs (including two for
James Jabara) and the Soviets claimed four Sabres (including one for
Yevgeny Pepelyaev). In fact, each side lost only one aircraft. The Americans claimed that Jabara was their first jet ace after the 20 May combat but, apart from the discrepancy on that date, he was also credited with a kill in a 12 April 1951 combat in which the Americans claimed a total of 11 MiGs shot down when the Soviets actually lost only one fighter. For their part, the Soviets claimed 15
Boeing B-29 kills on that date when the Americans only lost four in the combat itself and six written-off later. Compounding the problem, both sides were using
jet engine-powered
fighter aircraft on a large scale for the first time, and the high speeds of combat made visual identification of damaged and destroyed aircraft difficult. USAF pilots were credited with a kill if the gun camera showed their guns striking the enemy aircraft even if no one actually saw it go down. After the war the USAF reviewed its figures in an investigation code-named
Sabre Measure Charlie and downgraded the kill ratio of the
North American F-86 Sabre against the
Mikoyan-Gurevich MiG-15 by half. The Soviets also had lax standards for confirming kills at the beginning of the war, leading to widespread over-claiming. Both sides made extensive use of
gun cameras to better track effectiveness, but Soviet cameras were less effective, further contributing to over-claiming. Records from the
United Nations show that 40 American pilots reached ace status. However, records from
China, the
Soviet Union, and
North Korea conflict widely and accounts vary on how many aircraft on each side were lost and who is credited with the victories. Air victory claims, which are often controversial between two sides of a war, were particularly difficult to measure in Korea thanks to the difficulty recovering crashed aircraft and confirming losses, as well as poor records for the two sides which fought the bulk of their engagements in an area known as
MiG Alley. The number of aircraft lost during the war is in dispute among both the UN and the
Soviet bloc nations. UN pilots claim 840 aircraft shot down during the war, while Chinese, Soviet, and North Korean sources indicate only 600 were lost among the three nations, including non-combat losses. Conversely, the Soviet Union sources claim to have shot down 800 UN aircraft, while the US claims to have lost only 100 aircraft in combat. Overestimation of victories on both sides has been attributed to the stress and confusion of air combat situations during the war, as well as the tendency for pilots to deliberately exaggerate claims for career advancement. Conversely, data-matching with Soviet records shows that US pilots claimed up to 400 per cent more kills in some combats than they actually achieved, and that they routinely attributed their own combat losses to landing accidents and "other causes". The Soviet bloc nations claim to have destroyed a combined total of between 1,000 and 1,600 UN aircraft in air-to-air combat, the most common number in sources being 1,106 UN aircraft total, including 651
F-86 Sabres. The most authoritative Soviet numbers indicate 1,016 UN aircraft, including 595 Sabres. Chinese sources claim an additional 330 victories, including 211 Sabres. The most common number used is a total of 271 victories for China and North Korea. Other, more recent works claim 1,337 UN aircraft. During the entire course of the war, UN air forces lost about 3,000 aircraft. The
United States Air Force (USAF) reported a total of 516 non-combat losses and 1,466 aircraft lost in combat missions, with 757 of them lost to enemy fire Of these 139 were destroyed in air-to-air combat, 305 were unknown causes and 472 were "other losses". Of these, just 78 Sabres were listed as lost in air-to-air combat, 26 were unknown causes and 61 were "other losses". The
United States Navy and
United States Marine Corps lost 1,248 aircraft to all causes and the other UN countries lost about 300 aircraft. Tallying claims for the many Soviet pilots who claim to have achieved ace status is extremely difficult. The system of claims awards in the Soviet Union was unclear and appears to have been highly inconsistent during the war. There is also no single list of victories for each pilot in the Soviet Union, with numbers instead drawn from
after action reports and accounts from pilots and unit leaders. These complications, in addition to the intentional exaggeration of kills in order to please superiors, means that the about 50 Soviet pilots claiming ace status have a total number of victories which far exceeds the number of aircraft the UN lost in the Korean War's air battles. For example, the US claimed that
James Jabara became the world's first jet-versus-jet ace during his first tour of duty, but Soviet data shows he didn't achieve ace status until his second tour. ==List of aces==