The HAL HJT-36 Sitara (Sitārā: "star") is a subsonic intermediate jet trainer aircraft designed and developed by Aircraft Research and Design Centre (ARDC) and built by Hindustan Aeronautics Limited (HAL) for the Indian Air Force and the Indian Navy. The HJT-36 will replace the HAL HJT-16 Kiran as the Stage-2 trainer for the two forces. The Sitara is a conventional jet trainer with low swept wings, tandem cockpit and small air intakes for the engine on either side of its fuselage. It entered limited series production by 2010 but according to the Indian Air Force officials it remained "unfit" for service due to technological issues related to spin test (as of March 2017)., an issue which was only solved in tests in January 2022. In April 2019, Sitara flew for the first time in three years with a modified air frame to correct its spin characteristics. Design & development 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 HAL a contract for the development, testing, and certification of two prototype IJT aircraft. HJT-36 uses light alloys and composites, with a conventional low wing design with 18° leading-edge sweepback and a 9.8m wingspan. It features a hydraulically retractable tricycle-type landing gear. The single-wheeled main units retract inward and the twin nose wheel unit retracts forward. About a quarter of the aircraft's line replaceable units are common between it and the HAL Tejas trainer variant. In the cockpit, the HJT-36 has a conventional tandem two-seat configuration with the trainee pilot forward and the instructor in the raised seat to the rear. The single-piece canopy gives both pilots good, all-round vision. The prototype aircraft used Zvezda K-26LT lightweight zero-zero ejection seats. However, these may be replaced with Martin-Baker Mk.16 IN16S seats, due to a price escalation of the former. The pilots have both conventional and manual flight controls. The trainer has a full glass cockpit with a layout similar to current generation combat aircraft. It uses an integrated digital avionics system from GE Aviation Systems. Head-up display and repeater is produced by Elbit Systems. The aircraft has five external hardpoints for weapons training. There is one center-line hardpoint under the fuselage and two-weapon pylons under each wing for carrying rockets,