The HAL Tejas (Sanskrit: "Radiance") is a compact supersonic multirole interceptor fighter aircraft being developed by India. ADA (Aeronautical Development Agency) of Department of Defence R&D is the nodal agency for the design & development of Tejas for the Indian Air Force (IAF). HAL (Hindustan Aeronautics Limited) is the principal partner in Tejas Programme with participation of DRDO & CSIR Laboratories, Public & private sector industries and academic institutions. The first test flight was conducted in 2001 and over 538 flights have been conducted since then. It is likely to enter IAF's mainstream in 2009-2010. Tejas is meant to replace the ageing MiG-21 aircraft, which currently form the backbone of the IAF.