Unconfirmed reports indicate, Hindustan Aeronautics Limited (HAL) has issued a Request for Information (RFI) for a jet engine to power its Hindustan Lead-in Fighter Trainer (HLFT-42), a next-generation supersonic lead-in fighter trainer jet. The RFI specifies a maximum thrust requirement of 95-100 kN and a total technical life of 6,000 hours for the engine.

The HLFT-42 is designed to serve as an advanced training platform for pilots transitioning to more complex aircraft like the TEJAS MK-2 and Advanced Medium Combat Aircraft (AMCA), with an emphasis on enhancing pilot readiness for 4.5 and 5th generation fighter jets.

Initially, HAL considered using the General Electric F414 engine, which delivers around 98 kN of thrust; however, they are now seeking more powerful options to meet the specific performance needs of the HLFT-42. One potential candidate is the AL-31F engine, which produces 123 kN of thrust and has a proven track record in various combat roles, including on the Sukhoi Su-30MKI aircraft used by the Indian Air Force. Its relatively low cost of approximately $10.8 million per unit makes it an attractive option for HAL, aligning with their goals of maintaining cost-effectiveness while ensuring high performance.

Another option HAL can explore is the indigenous GTRE's GTX-35VS Kaveri engine. The suitability of GTX-35VS Kaveri engine for HAL's HLFT-42 trainer jet is a topic of interest, particularly given the engine's specifications and intended applications.

The GTX-35VS Kaveri is an afterburning turbofan engine developed by the Gas Turbine Research Establishment (GTRE) in India. It was initially designed to power the HAL TEJAS Light Combat Aircraft but has faced challenges in meeting performance requirements, leading to its delinking from that program in 2008. As of 2024, the engine is being refined, with a dry variant under development for other applications like the DRDO Ghatak unmanned combat vehicle.

The Kaveri engine can produce up to 81 kN (18,100 lb f) with afterburner and approximately 52 kN (11,700 lb f) in military configuration. Besides the TEJAS and Ghatak, it is also planned for use in HAL's Advanced Medium Combat Aircraft (AMCA) MK-2.

The thrust provided by the Kaveri engine aligns well with the requirements for a trainer jet like the HLFT-42. The thrust levels are adequate for manoeuvrability and performance during training exercises. As the Kaveri engine continues to evolve, its integration into new platforms remains a focus. The HLFT-42's design could potentially benefit from the Kaveri's capabilities if it meets reliability and performance standards.

While the GTX-35VS Kaveri engine has potential suitability for HAL's HLFT-42 trainer jet based on its thrust and performance characteristics, ongoing developments and testing will ultimately determine its effectiveness and reliability in this application.

The HLFT-42 is not only envisioned as a training aircraft but also as a versatile platform capable of performing combat missions. It is designed to carry advanced weaponry, including close-combat missiles and beyond-visual-range missiles, thereby expanding its operational capabilities. As part of its dual-role design, the aircraft may also serve as a "Mothership" for unmanned aerial systems, enhancing its functionality in modern combat scenarios.

As HAL navigates the engine selection process, it must balance performance requirements with budget constraints. The HLFT-42 is expected to play a critical role in India's defence training infrastructure, bridging the gap between basic trainers and frontline combat aircraft while supporting India's broader objectives in defence manufacturing and self-reliance.

About HLFT-42 Supersonic Trainer

The HLFT-42 is an ambitious next-generation supersonic trainer aircraft being developed by Hindustan Aeronautics Limited (HAL). Conceived in 2017, the HLFT-42 aims to serve dual roles: advanced pilot training for modern combat aircraft and light combat missions.

Equipped with state-of-the-art avionics, including Active Electronically Scanned Array (AESA) radar, Electronic Warfare (EW) Suite, Infrared Search and Track (IRST), and Fly-By-Wire (FBW) control system. Designed for advanced pilot training for platforms like TEJAS MK-2, Advanced Medium Combat Aircraft (AMCA), and Multi-Role Fighter Aircraft (MRFA).

The HLFT-42 is not limited to training; it can perform light combat missions with a payload capacity of up to 4.5 tons. It features 11 hard-points capable of carrying a variety of weapons, including air-to-air missiles (Astra MK-1/2, ASRAAM), air-to-surface missiles (BrahMos-NG), anti-ship missiles, precision-guided bombs, and countermeasures like chaffs and flares.

The fighter will be a single-engine supersonic platform inspired by HAL's TEJAS Light Combat Aircraft program. Projected specifications include a maximum take-off weight of 16.5 tons, internal fuel capacity of 3,500 kg, and advanced aerodynamic stability through design refinements.

The project is self-funded by HAL but includes plans to collaborate with private defence entities for prototype development. Wind tunnel testing and fabrication of the prototype are expected to take another two years. The rollout date is projected for the early 2030s due to challenges like engine selection and design refinements.

The HLFT-42 is intended to replace the Indian Air Force’s ageing BAE Hawk-132 trainers while bridging the gap between subsonic jet training and frontline fighter platforms like MiG-21s and Su-30MKIs.

HAL has yet to finalise an engine powerful enough for the HLFT-42’s requirements. Speculation suggests it may use a 110kN engine being developed for the AMCA program, though this engine may not be ready before 2035.

Program Prioritisation

HAL’s focus remains on more immediate programs like TEJAS MK-1A/MK-2 and AMCA, which could delay the HLFT-42’s development timeline.

The HLFT-42 represents a significant leap in India’s aerospace capabilities, combining advanced training systems with combat readiness while offering export potential. However, its success depends on overcoming technical challenges and aligning priorities within HAL’s broader development roadmap.

IDN