HAL's Intermediate Jet Trainer Demonstrates Six Turn Spins

India’s Hindustan Aeronautics Limited (HAL) has announced that the Intermediate Jet Trainer (IJT) also known as the HJT-36 Sitara carried out six turn spins to the right as well as left.

The spin testing of an aircraft is the most crucial phase of its flight testing. Tests of the IJT were put on hold after the aircraft had encountered problem in the spin test flights in the year 2016. Spin tests of the aircraft resumed after four years in late 2020.

The company had to redesign the aircraft by moving the vertical tail aft and extending the rudder surface with advice from U.S. aviation technology and Bihrle Applied Research Inc. testing firm. It resulted in significant airframe changes, first visible when the redesigned jet flew in April 2019. HAL said the changes were incorporated in two aircraft with the involvement and clearance from certification agencies after every stage.

Post modification, the jets underwent significant flight tests to assess the general handling with the new configuration of fin and rudder. They have now been incorporated with necessary safety devices such as Anti-Spin Parachute Systems. During the first flight, initially, the aircraft was taken through one turn spin to the left and right, to test the spin characteristics.

The IJT is designed to replace Indian Air Force (IAF)’s ageing fleet of KIRAN Jet Trainer aircraft for Stage-II training of its pilots. It is powered by AL-55I engines produced in-house at HAL Engine Division, Koraput. The aircraft incorporates the simplicity necessary for ease of conversion from Basic Piston Trainer and the sophistication required for quick conversion to the complexities of an Advanced Jet Trainer. The jet can reach speeds of upto 750 kmph.

The development of the HJT-36 trainer aircraft is in the final stages of flight certification tests, which should confirm if it meets the requirements of the IAF.

The IJT has already been tested to its full envelope in terms of speed, altitude and load factor (‘g’ envelope). It has also been integrated with drop tanks and bombs.