Dissimilar air combat training Dissimilar air combat training ( DACT ) was introduced as a formal part of US air combat training after disappointing aerial combat exchange rates in the Vietnam War . Traditionally , pilots would undertake air combat training against similar aircraft . For example , pilots of F - 8s would seldom train against F - 4 Phantom II s , and almost never against A - 4 Skyhawk s and never as part of a formal syllabus . From 1965 to 1968 , US pilots found themselves over the skies of North Vietnam pitted against smaller , more nimble subsonic Soviet MiG - 17 and the supersonic MiG - 21 . US pilots in USAF F - 105 Thunderchiefs were barely able to exceed parity , and pilots in Phantoms and Crusaders were not able to achieve the hugely lopsided win / loss ratio achieved over Korea and in World War II . In fact , Air Combat Maneuvering ( ACM ) was not practiced by all fighter squadrons for a variety of reasons . The USAF had deemphasized ACM since most air combat doctrine since the late 1950s , centered around delivering nuclear weapons over Europe , or firing missiles at beyond visual range at bombers , not daylight dogfighting , which was thought to be obsolete in the missile age . The primary US fighter used against North Vietnamese MiGs , the F - 4 Phantom , did not even have an internal gun . Yet , US pilots were finding themselves hard - pressed to prevail over the nimble VPAF MiGs and by late 1966 , they had grown to be a real threat to US aircraft operating over the North . Even more vexing were rules of engagement ( ROE ) that did not even permit beyond - visual - range ( BVR ) firing of missiles . Radar - guided AIM - 7 Sparrow s experienced high failure rates , and the short range Sidewinder was ineffective in many dogfighting maneuvering situations . It was found that Phantom training against other Phantoms did not reflect the reality of a target that was smaller , smokeless , and more agile . Ever since the success of the American Volunteer Group ( Flying Tigers ) , aerial tacticians have advocated exploiting known differences in aircraft to maximize one ' s own advantages while minimizing the disadvantages of one ' s own platform , thus neutralizing the superior maneuverability and climbing speed of , for example , a Zero compared to the rugged , fast - diving and powerfully armed P - 40 Tomahawk . However , US pilots found themselves the victims of VPAF MiG - 21s using Chennault ' s Flying Tiger tactics of hit and run attacks successfully against them . In 1968 , the Navy took a hard look at its air - to - air problems over North Vietnam and tasked Captain Frank Ault to come up with recommendations to improve the situation . His report became known as the Ault Report and it resulted in establishment of TOPGUN and incorporation of DACT into the syllabus . The United States Navy Fighter Weapons School adopted the nimble subsonic A - 4 Skyhawk to simulate subsonic Soviet fighters , while the F - 5E Tiger simulated the supersonic MiG - 21 Fishbed fighter . Both the Skyhawk and Tiger were used in the 1986 film " Top Gun " . After aerial combat resumed again in 1972 over North Vietnam , the Navy had numerous TOPGUN graduates who were ready to take on the VPAF MiG - 17 , MiG - 19 and MiG - 21 pilots that had also been training and were prepared for the resumption of hostilities . The Navy ' s exchange ratio soared to over 20 : 1 before loss of a Marine Phantom brought it to 12 . 5 : 1 by 1973 ; an unqualified testament to the value of the TOPGUN approach and DACT . The USAF did not improve its exchange ratio at all in the same timeframe and hurriedly began to adopt DACT even inviting Navy F - 8 Crusader s to visit a base in Thailand in 1972 to conduct DACT with the F - 4 Phantoms based there . The A - 4 Skyhawk has since been replaced by the T - 45 Goshawk , a navalized British Hawk trainer . F - 16s have been used to simulate later generation Soviet fighters such as the MiG - 29 . The now - retired F - 14 Tomcat was also used in various paint schemes to simulate Iranian F - 14s , as well as the large Su - 27 Flanker . The Air Force has reportedly also used actual captured or purchased Soviet fighters on occasion .