India's state-run aircraft maker Hindustan Aeronautics Ltd will unveil a mock-up display of its Combat Air Trainer, a twin-engine home grown Advanced Jet Trainer, during the Aero India show that begins in Bangalore on Wednesday.

The scaled down model of CAT is to demonstrate HAL's plan to build the all-composite AJT by 2010 to be designed as a far advanced aircraft than the British Hawk AJT but slightly less complex than Tejas, the indigenous Light Combat Aircraft, HAL officials told PTI.

Indian Air Force engineers are close to freezing the design for CAT which will have a glass cockpit, modern avionics with ability to fly at transonic speed (speed of sound) and also be deployed for combat operations.

HAL is confident of rolling out the first prototype of CAT in 39 months after government sanction for the project at a cost of Rs 750 crore.

The CAT is a logical upgrade over the Intermediate Jet Trainer which HAL's engineers developed and flew in 22 months from the drawing board stage using technologies from the LCA programme.

Russia's [Images] NPS Lyulka Saturn and HAL are developing a higher thrust 1,700 kg AL-551 engine to power the IJT when it is inducted into the IAF and also likely for the CAT aircraft.

HAL officials say that the CAT project should be able to take off around 2007 with the first flight by 2010, when the last of the 66 Hawk AJTs, for which India signed a deal last year, is inducted into the IAF.