IJT begins spin flight testing

Bengaluru: The indigenous Intermediate Jet Trainer (IJT) designed and developed by the Hindustan Aeronautics Limited to replace the ageing Kiran aircraft fleet of the Indian Air Force (IAF) commenced spin flight testing in Bengaluru. The flight was piloted by HAL's test pilots Group Caption H V Thakur (Retd) and Wing Commander P Avasti (Retd).

The spin testing of an aircraft is the most crucial phase of its flight testing. Accordingly, the testing will be gradually progressed to assess the behaviour of the aircraft till six turn spins to either side to meet the targeted requirement.

The IJT has already been tested to its full envelope in terms of speed, altitude and load factor ('G' envelope) and has also been integrated with drop tanks as well as bombs. For spin test, HAL redesigned the aircraft by moving the vertical tail aft and extending the rudder surface. These changes for ensuring a satisfactory spin behaviour required extensive redesign of the rear fuselage and the rudder. The changes have been incorporated in two aircraft with the involvement and clearance from certification agencies at every stage. Post modification, the two aircraft underwent significant flight tests to assess the general handling with the new configuration of fin and rudder. These aircraft have now been incorporated with the necessary safety devices (Anti-Spin Parachute Systems). During the first flight, initially the aircraft was taken through one turn spin to the left and right hand sides to test the spin characteristics.

The official also maintained that these aircraft have now been incorporated with the necessary safety devices (Anti-Spin Parachute Systems).

The IJT will replace KIRAN Jet Trainer aircraft in service with IAF for Stage II training of its pilots.

IJT is fitted with AL-55i Jet engines produced in house at Engine Division Koraput. IJT 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 IJT's spin test assumes significance, as this project was grounded till April last year due to design flaws and series of mishaps.

The IJT programme was initiated in 1999 and two prototypes of the aircraft were built subsequently. However, a couple of accidents involving the prototypes became a major setback for the IJT programme.

During the Aero India 2007, an IJT swerved of the runway at the Air Force Station Yelahanka after its canopy opened just as the pilot was getting airborne. In April 2011 another prototype version of the aircraft met with an accident in Krishnagiri District, Tamil Nadu during a test sortie.

Due to design flaws and delays in induction -- Surya Kiran aerobatics team -- a cynosure of the biennial Aero India Show since its inception in 1996, have been flying the Hawk Mk-132 Advanced Jet Trainer (AJT) instead.