Sitara HJT-36 Intermediate Jet Trainer

The HJT-36 Sitara [Star] Intermediate Jet Trainer project was expected to replace the IAF's aging Kiran aircraft. HAL's main focus was on the single engine HJT-36, which was intended to replace the 200-odd HJT-16s as the intermediate jet trainer.

The HJT-36 Intermediate Jet Trainer (IJT), was being developed for training of pilots. IJT was to replace the ageing Kiran trainers. HJT-36 is an indigenous product developed by the Hindustan Aeronautics Ltd, Bangalore. It is a sub-sonic aircraft with a fuel-efficient engine, advanced avionics systems and increased weapon load. This will help to improve the pilots' training effectiveness and lead to easier transition to the advanced training for modern fighter aircraft.

As of June 2002 India's HJT-36 intermediate jet trainer project was running behind the schedule. As of mid-2003 initial operational clearance of IJT was expected by 2005-06 and deliveries to Indian Air Force are expected to start from the same year onwards. As of 2003, around 150 aircraft were expected to be procured by the Indian Air Force to replace the ageing Kiran trainers, which had been in use with the IAF for nearly 30 years.

The project was sanctioned in July 1999 with a grant of Rs 180 crore. The powerplant will be the Snecma Larzac 04-30 turbofan engine and the semi-glass cockpit will have French/British avionics with the pilot seated on a Zwezda K36CT ejection seat. Assembly of aircraft and integration of all systems is expected to be complete in 20 months. The rollout was planned for August 2002 and first flight in October 2002. The PT2 was to follow in six months and flight testing would total 4,500 hours leading to series production in 2004-05. The plan was to build 225 HJT36s.

HAL had pegged the overall project cost at Rs.200 crores and expected the prototype to roll out 39 months after it gets the go-ahead. The plane was to enter service two years thereafter. HAL engineers said that the project cost had been capped at Rs.18 crores.

HAL was looking for "off-the-shelf" equipment in order to save time and money. About 200 vendors have so far been identified. In June 2001 Smiths Aerospace and Hindustan Aeronautics Limited (HAL) signed a contract for the design and development of the Integrated Avionics System for the HJT-36 Intermediate Jet Trainer. The system consists of an open systems architecture mission computer, head up display, HUD repeater, rear data entry panel, attitude and heading reference system and air data computers.

The IJT made it's maiden flight in March 2003, just 20 months after the project was actually taken up. But two back to back accidents in 2005 and 2007 air shows, and an engine change program sent the project into a tail spin.

The prototypes were initially fitted with the the French company Snecma's Larzac 04-30 turbofan engine. However, in 2005, Russia and India signed a pact to transfer technology to HAL to develop the AL-55I engine for the IJT. As per the agreement, India was issued a licence by NPO Saturn, a Russian aerospace firm, for making the AL-55I engines at its Koraphut complex in Orissa. The AL-55I will propel the subsequently produced IJTs. HAL estimated a demand for about 200 IJTs from the Indian Air Force (IAF) for training its fighter pilots.

The estimated cost of the development is Rs. 1.85 billion. Around 1,000 engines are expected to be produced by HAL since it is estimated that each IJT needs four engines during its lifetime of 20,000-25,000 flying hours. The AL-55I engine will have a power thrust of 1.7 tonnes, higher than the 1.4 tonnes of the French engine fitted in two IJT prototypes initially underwent development test flights.

As of 2005, the IAF had placed an order for 16 IJTs. It was estimated that HAL will produce about 20 trainers per year. As per the original schedule the first batch of IJTs was to have been delivered to the Air Force in 2005-06., now June 2010. Besides the 12 LSP aircraft HAL received an order for 60 production aircraft.

In June 2006 the intermediate jet trainer passed the first phase of hot weather trials. The two prototypes, PT1 and PT2, had logged eight hours within a week during tests conducted at Nagpur. Planned for induction into the IAF in early 2008, the IJT's performance was once more milestone towards certification, said the HAL Chairman, Mr Ashok Baweja.

In February 2007 a prototype version of the Intermediate Jet Trainer careened off the runway after its canopy inadvertently opened just as the pilot was getting airborne for an aerobatic sortie at Aero India 2007 exposition, triggering a wave of panic on Thursday afternoon. With the canopy opening on one side, the aircraft tilted and lost balance and shot off the runway. When the aircraft pulled back to the runway, a tire burst. The aircraft's right wing was damaged, and unconfirmed reports said the undercarriage was also broken.

On 28 April 2011 two test pilots of a trainer aircraft belonging to Hindustan Aeronautics Ltd (HAL) ejected to safety minutes before the plane crashed near a forest in Krishnagiri district of Karnataka. According to Krishnagiri police officials, the Intermediate Jet Trainer (IJT) aircraft crashed in an area near the forest Thursday afternoon and the pilots have been rescued and flown back to Bangalore. The aircraft was totally damaged by fire and security personnel from HAL had reached the site, besides Tamil Nadu police. HAL said the IJT prototype aircraft was carrying out routine flight testing when it met with a mishap.

By 2013 HAL had not abandoned its commitment of manufacturing an intermediate jet trainer (IJT) for stage 2 training of the rookie fighter pilots of the IAF. In Febraury 2013 it was reported that BAE Systems, the multinational aerospace major, had said it would offer consultancy to sort out some of the issues the Intermediate jet trainer (IJT), being manufactured by Hindustan Aeronautics Limited, was facing. The issues pertaining to aerodynamics and the poor manoeuvrability of the aircraft was said to have been chief worries on the IJT front. It was especially with regards to the issues faced by the aircraft during a high angle of attack that had been a cause for concern.

The Bangalore headquartered PSU under the Defence Ministry had faced flak from all quarters for delay in the production of IJT. HAL had been working to develop the IJT, or the Sitara, since 1999. The government had paid about Rs 600 crore (up from an initial estimate of Rs 180 crore) in Reserach and Development (R&D) costs. One prototype aircraft and three Limited Series Production aircraft were being flight tested in 2013 towards obtaining IOC.

On 13 March 2013 the Indian Air Force (IAF) signed two contracts with HAL for delivery of 12 Limited Series Production Intermediate Jet Trainer (IJT) aircraft and 73 Series Production IJT aircraft. The IJT aircraft was targeted to be inducted in IAF in the year 2014 onwards. HAL has confirmed the delivery of aircraft in a phased manner after grant of Initial Operational Clearance.

HAL began design work onthen Intermediate Jet Trainer (IJT) designated HJT-36 Sitara in 1997. After 15 years of design and development, HAL admitted that the IJT needs basic design review. The then defence minister Arun Jaitley informed the Parliament in August 2014 that the IJT program was well behind schedule and has not so far been able to resolve critical wing and airframe design and development issues related to stall and spin. To circumvent the stall and spin characteristics problems help of a foreign consultant was sought, who suggested major airframe modification that could push the programme further back.

Till date over 4,000 crore had been already committed. The 73 IJT aircraft with associated spares and equipment would require multiples of additional funds. With the heavier Russian engine the final performance may remain in question. HAL BTA has yet to be given a go ahead.

Engineers and designers at HAL’s Aircraft Research & Design Centre had the daunting task of identifying and correcting the inherent asymmetry of the aircraft. HAL hoped to get the Initial Operational Clearance for the IJT by the end of December 2013, though insiders said the deadline might get pushed to 2015.

The Russian engine needed to be overhauled more frequently than suited the Air Force. The engine would need to be overhauled about every 150 hours of flying, while the air force wants the engine to operate at least 900 hours before an overhaul is needed. A Russian diplomat, however, said the engine meets the basic requirements of the IJT, adding that the service life of the engine was being increased to 500 hours.

“The project suffered at every stage of its execution,” said a report by India’s Comptroller & Auditor General. “While the planning went awry with indecisiveness about the weight, thrust and life of the engine at the design stage itself, taking up production without Initial Operational Clearance did not serve the purpose of the IAF, which had projected requirement for the aircraft way back in 1999.” The IJT project has exposed the rudimentary state of Indian aeronautics. When it comes to state of the art aircraft, India seems to be good only at screwdriver technology – which is euphemistically described as locally assembled.