The HAL HJT 39, aka CAT (Combat Air Trainer), was an Advanced Jet Trainer (AJT) project proposal by Hindustan Aeronautics Limited (HAL) for the Indian Air Force. HAL HJT 39 CAT Programme was Announced at Aero India, February 2005, with mockup of front fuselage and cockpit shown. It was projected to fly within three and a half years of go-ahead with airframe and engine commonality with HAL HJT-36 Sitara, avionics comparable with those of HJT-36 and HAL Tejas. CAT was planned as a twin engine transonic “Lead in Fighter Trainer” (LIFT) with a very substantial ground attack capability with a maximum speed of 1,000 km/h. CAT was to feature Multi Function Displays (MFD) for tactical navigation, Radar Warning Receiver (RWR) and indigenous CSIO/BEL-developed Head Up Display (HUD) and Up Front Control Panel (UFCP), used on the LCA. The HUD would display both navigation and weapon aiming. CAT also features redundancy features like stand by instrumentation system, Fly-by-Wire (FBW), hands-on-throttle-and-stick HOTAS), INS along with GPS receiver, flight control computer and display processor. The avionics would be confirming 32-bit dual mil 1553B Bus Standard. The FBW planned consist two digital channels and one engine analog channel. Full Authority Digital Engine Control (FADEC) will be implemented for better handling. Some other features of the modern cockpit are automatic pressure cabin and temperature control systems, zero / zero ejection seat and crew emergency escape system. Radar is optional, but a new radar is to be developed. Among the prominent External design features revealed were a moderately-swept wing, with no wing-body blending or wing root strakes, a prominent vertical fin. The low wing sweep will give a good low-speed performance and excellent handling characteristics essential for the trainer role. The wing will also have a clean leading edge, while having high-lift devices on the trailing edge, for good runway performance. The HJT-39 will be an all-composite aircraft.