In the late 1960s, both the US and USSR witnessed the doctrinal advantages of supposedly "outdated" lightweight, highly agile fighters over the skies of Vietnam, and learned the harsh lesson that large missile trucks were not the future of air combat as they had anticipated. As such, the US and USSR quickly raced to develop new lightweight, high manoeuvrability air superiority fighters to replace their F-4 Phantom II and MiG-23 "missile trucks". With both designs being initially very similar for a frontline lightweight fighter, Mikoyan OKB would implement multiple new features in their Perspektivnyy Lyogkiy Frontovoy Istrebitel (LPFI, or "Advanced Lightweight Tactical Fighter") program over the American F-16, such as a second engine for redundancy and more thrust, a far more powerful radar and long range BVR missiles, and most famously, the "Kill-on-sight" doctrine involving the R-73 "High Off-Boresight" dogfight missile and the Shchel-3UM/Zsh-5 helmet-mounted targeting system, giving the MiG-29 an unparalleled advantage in close range dogfighting over any of its adversaries of the time. The aircraft's development would be plagued with problems, and would undergo multiple design changing decisions, such as accomodation of the R-73 missile after the R-14M1 was cancelled, and the cost saving measures required to field the Fulcrum at a 2:1 ratio over its heavier brother, the Sukhoi Su-27. In the end, the initial pre-production variant of the Fulcrum as we know it (titled the MiG-29A) would first take to the skies on October 6th, 1977, marking the beginning of a new era of military aviation in the Eastern world.