HAL started design work on an intermediate jet trainer in 1997. The concept was developed as a successor to HAL's earlier trainer, the HJT-16
Kiran, introduced in 1968. In 1999, following reviews by the Indian Air Force, the
Government of India awarded Hindustan Aeronautics a contract for the development, testing, and certification of two prototype IJT aircraft at the cost of . The completion of the contract was scheduled in July 2004.
2000s • The first and second prototypes of the HJT-36, labeled PT-1 and PT-2, serialed S3474 and S3466, flew on 7 March 2003 and in March 2004, respectively. • In April 2005, the project cost was revised to and timeline for
Initial Operational Clearance (IOC) and the
Final Operational Clearance (FOC) was expected in 2006-07 and 2007-08, respectively. • On 8 February 2007, IJT prototype PT-1 overshot the runway at
Yelehanka AFS during the inauguration of
Aero India after its tyres burst during take-off. • In November 2008, Air HQ initiated a proposal to for supply of 73 SP IJT aircraft from HAL. • Following the crashes and delays, in March 2009, the IOC and FOC dates were shifted to 2009-10 and 2010-11, respectively. Following ground taxiing trials, flight tests with the new engine started on 9 May 2009. However, the Russian-origin was relatively newly developed compared to the Larzac, which had 0.85 million hours of flight. This led to "teething problems" in the engines which eventually lowered the availability of the IJT prototypes and limited series production variants for test flights.
2010s • |alt=|rightIn March 2010, the Air Force placed an order for 73 HJT-36 trainers for serial production at a cost of , again before the completion of IOC certification and deliveries of LSP aircraft. Clearance for the contract was approved by the CCS in February. As per MoD, the LSP aircraft order would be completed by 2011-12 and the timeline for delivery of 73 SP aircraft was between 2013 and 2017. As per delivery timeline, 6 aircraft would have to be delivered in 2013, followed by 24 aircraft in 2014 An advance payment of was done. and initial operational capability was expected by July 2011. • On 28 April 2011, the first prototype (S3466) crashed in near
Hosur during routine test flight in
Krishnagiri district,
Tamil Nadu. Both the pilots,
Group Captain Anant Mathur of HAL and co-pilot
Wing Commander Patra of Aircraft and Systems Testing Establishment (ASTE), ejected safely. The aircraft was lost in the accident. • On 27 July 2012, first Engine Ground Run was performed on third prototype. • In December 2013, HAL declared that Sitara was 'weeks' from certification. • On 19 February 2014, the Indian MoD submitted a statement that the development of IJT was in the advanced stages of certification, with more than 800 test flights completed so far. The activities were progressing well with completion of sea level trials, night flying trials, high altitude trials as well as weapon and drop tank trials. The activities left for obtaining Final Operational Clearance (FOC) are the refinement of stall characteristics, and spin testing which will be commenced as soon as stall characteristics were refined. All efforts were being made to achieve FOC by December 2014. Production of aircraft was to commence immediately thereafter. However the stall cannot be tested until HAL redesigns the entire aircraft to correct its "inherent asymmetry". • As of July 2014, 6 of the LSP aircraft were produced but still not delivered due to non completion of Design and Development (D&D) activities. Afterwards the design was put to mathematical and
wind tunnel tests. The modified aircraft was expected to complete the spin tests by September 2015, and the production of 85 aircraft for the Indian Air Force to begin. • In 2016, the programme and the testing came to a halt after the aircraft “departed from controlled flight” while testing spin characteristics. Post modifications, a new Anti-Spin Parachute system (ASPS) was developed to ensure safety of the aircraft and test crew during spin flight testing. Major design changes were executed in the
empennage with the vertical fins pushed back by a metre and the
rudder extended beyond the vertical stabiliser until the rear fuselage, increasing the control surface area by 30%. Other control surfaces that were added as compared to the original design included nose strakes, ventral fins and a
leading edge strakes at the
wing root. • In February 2025, at the Aero India 2025, HAL renamed the HJT-36 Sitara as the HJT-36 'Yashas'. The renaming was due to its design modification to correct "departure characteristics and spin resistance". The aircraft was recently integrated with "state-of-the-art avionics and an ultra-modern cockpit". This upgrades videos the overall weight of the aircraft and replaced the obsolete foreign
line-replaceable units with Indian LRUs. • On 12 February 2025, it was also reported that the Indian Air Force has not placed any order for the updated aircraft but would lease 4 to 5 'Yashas' from HAL. Further orders will be placed if the user was satisfied with its training and operational capabilities. == Design ==