The HAL Tejas is an Indian, single engine, delta wing, light multirole fighter designed by the Aeronautical Development Agency (ADA) in collaboration with Aircraft Research and Design Centre (ARDC) of Hindustan Aeronautics Limited (HAL) for the Indian Air Force and Indian Navy. It was developed from the Light Combat Aircraft (LCA) programme, which began in the 1980s to replace India's ageing MiG-21 fighters but later became part of a general fleet modernisation programme. In 2003, the LCA was officially named "Tejas". It is the smallest and lightest in its class of contemporary supersonic combat aircraft. The Tejas is the second fighter developed by HAL with the intention of supersonic performance, after the HAL HF-24 Marut. The Tejas achieved initial operational clearance in 2011 and final operational clearance in 2019. The first Tejas squadron became operational in 2016, as No. 45 Squadron IAF Flying Daggers was the first to have their MiG-21s replaced with the Tejas. The Tejas currently has three production models – Tejas Mark 1, Mark 1A and trainer. The IAF has ordered 40 Tejas Mark 1, 73 Tejas Mark 1A and 10 trainer aircraft. The IAF plans to procure 324 aircraft in all variants, including the Tejas Mark 2 currently under development. The Tejas Mark 2 is expected to be ready for series production by 2026. indigenous content in the Tejas Mark 1 is 59.7% by value and 75.5% by number of line replaceable units. The indigenous content of the Tejas Mk 1A is expected to be 50% and rise to 60% by the end of the programme. Development LCA programme The LCA programme originated in the early 1980s. In 1983, the Government of India established the LCA project with the initial goal to develop a new light combat aircraft to replace the ageing IAF fighters, especially the MiG-21 variants, which had been the mainstay of the IAF since 1963. At one point the IAF had operated as many as 874 MiG-21s. The "Long Term Re-Equipment Plan 1981" noted that most of these IAF fighters were approaching the end of their service lives by the early-1990s, and that by 1995, the IAF would be 40 percent short of the aircraft needed to fill its projected force structure requirements. In 1984, the Government of India established Aeronautical Development Agency (ADA) under the aegis of Defence Research and Development Organisation (DRDO) to manage the LCA programme. The ADA was entrusted