Hindustan Aeronautics Limited said it expected production clearance for the HTT-40 by the end of this year. HTT-40, the indigenously-built basic trainer aircraft, on Saturday cleared a challenging milestone — its first spin test — HAL said

BANGALORE: In flight-testing on Saturday in Bangalore, HAL’s test pilots threw the HTT-40 into multiple spins and, each time, the trainer returned to level flight smoothly. In so doing, the HTT-40 cleared the so-called “six-turn spin test”, regarded as the ultimate and most difficult test for a trainer aircraft.

A few more tests are due to follow before the aircraft can get its operational certification, likely in end-2019, according to a person familiar with the program.

HAL said it expected production clearance for the HTT-40 by the end of this year. The Defence Acquisition Council has approved buying of 70 HAL-built basic trainers for the Indian Air Force. The HTT-40, when acquired, will join the 75 Swiss Pilatus PC-7 Mark II trainers that are already in service.

Congratulating the design and project team, HAL CMD R. Madhavan said, “The successful start of the spin testing gives a boost to HAL and also restores its credibility in successfully designing a spin-worthy aircraft.”

The spin test is the most crucial phase in developing a safe and airworthy aircraft, according to HAL. Novice military pilots begin their flying careers with a basic trainer and then graduate on to fighters and transport planes.

“This is a big boost [for the team]. We got the spin right after two generations, the last was in the 1980s for the Kiran,” said the official associated with trainer development.

A statement said, “HTT-40 began the most awaited phase of the ‘spin test’ by successfully entering into a multiple-turn spin and subsequently recovering with the appropriate controls.”

HTT-40, too, had been earlier rejected by the IAF which opted for the imported Pilatus.

The HTT-40 has already met and, in many aspects of flight performance, surpassed the “Air Staff Qualitative Requirements” (ASQRs), which lists out the flight performance — speed, turn, ceiling, etc. — that the IAF demands from an aircraft.