From Tejas rejection to 5th-gen fighter jet hopes: Can Kaveri 2.0 finally deliver?

NEW DELHI: Nearly 18 years after India's indigenous Kaveri jet engine was dropped from the Tejas fighter programme, the project is showing signs of a revival. Defence Minister Rajnath Singh's call for DRDO scientists to develop sixth-generation fighter engines within the next five to seven years, recent successful afterburner tests of the Kaveri engine and the government's renewed push for self-reliance in military aviation have brought the long-delayed programme back into focus.While the original GTX-35VS Kaveri failed to meet the Indian Air Force's requirements for the Tejas Light Combat Aircraft (LCA), the technologies developed over more than three decades are now expected to support future programmes such as the Advanced Medium Combat Aircraft (AMCA), the Ghatak stealth unmanned combat aerial vehicle and marine gas turbines.The renewed focus comes as India continues to rely on imported General Electric engines for its frontline fighter fleet while pursuing an indigenous powerplant for next-generation combat aircraft.Rajnath Singh sets ambitious targetDuring a visit to DRDO's Gas Turbine Research Establishment (GTRE) in Bengaluru in February this year, defence minister Rajnath Singh urged scientists to compress decades of aero-engine development into a much shorter timeframe.Describing fighter engine development as one of the most technologically demanding areas of defence research, Rajnath said advanced countries typically require 25 to 30 years to develop new fighter engines."We must assume that 20 years have already passed and we now have only 5–7 years left."The minister also called on scientists to look beyond fifth-generation propulsion systems. "We are rapidly moving towards the design and development of the Advanced Medium Combat Aircraft (AMCA). We have made numerous attempts in the past to achieve expertise in the field of aero engines. Now, the time has come to complete those efforts. We cannot limit ourselves to only 5th generation engines. We must begin the development of the 6th generation. Research on them is the need of the hour. The use of AI, machine learning and new materials is increasing. We must stay ahead of the curve."During the visit, Rajnath also witnessed a successful full-afterburner test of the Kaveri engine, which used a newly designed afterburner developed with support from BrahMos Aerospace. The upgraded configuration is aimed at generating around 81-83 kilonewtons (kN) of thrust, bringing it closer to the levels required for future combat aircraft.Why the Kaveri engine was developedIndia approved the Kaveri engine programme in 1989 as part of the Light Combat Aircraft project to develop an indigenous afterburning turbofan engine for the Tejas fighter. The programme, led by DRDO's Gas Turbine Research Establishment (GTRE) in Bengaluru, was initially sanctioned at a cost of Rs 382 crore and was expected to be completed in less than eight years.The plan was for the early Tejas prototypes to fly with imported General Electric engines before production aircraft transitioned to the indigenous Kaveri. However, the programme soon encountered technological challenges that delayed development and ultimately prevented the engine from meeting the Indian Air Force's operational requirements.Why Kaveri failed to power TejasThe Kaveri programme fell short of the performance needed for the Tejas. The engine produced around 70-72 kN of afterburning thrust against the 83-85 kN required by the aircraft. It also remained about 150 kg heavier than its design target and faced persistent challenges related to turbine blade durability, compressor performance, afterburner efficiency, engine control systems, reliability and high-altitude operation.Developing a modern fighter engine is widely regarded as one of the most complex technological challenges in aerospace. It requires mastery of high-temperature metallurgy, single-crystal turbine blades, advanced compressor design, precision manufacturing and sophisticated Full Authority Digital Engine Control (FADEC) systems. The programme also faced external setbacks. International sanctions imposed after India's 1998 nuclear tests restricted access to critical technologies, specialised materials and testing facilities. India also lacked a dedicated high-altitude engine testing facility, forcing several rounds of testing to be conducted in Russia.Successive Comptroller and Auditor General (CAG) reports highlighted delays in achieving milestones, increasing development costs and technical deficiencies, including excessive engine weight and inadequate thrust. Former GTRE officials have argued that India attempted to develop an advanced fighter engine with a fraction of the funding invested by major aerospace powers. While modern Western fighter engine programmes typically require investments running into billions of dollars, India's expenditure on the Kaveri programme stood at around Rs 3,000 crore, according to the last official estimate presented in Parliament by then defence minister Manohar Parrikar in 2016.As development delays mounted, the government officially delinked the Kaveri from the Tejas programme in September 2008. The Tejas Mk-1 was powered by the General Electric F404-IN20 engine, while the more powerful F414 was later selected for the Tejas Mk-2 and the initial AMCA prototypes.Although the Kaveri never powered the Tejas, the programme established indigenous capabilities in high-temperature metallurgy, turbine blade manufacturing, compressor design, FADEC systems, gas turbine engineering and engine testing infrastructure. These technologies are now being applied to future indigenous propulsion programmes and are expected to form the foundation of India's next-generation fighter engine efforts.Kaveri's second lifeThe Kaveri programme did not end with its rejection from the Tejas. Instead, it has gradually evolved into a broader indigenous aero-engine effort, with technologies developed over three decades being adapted for unmanned combat aircraft, marine propulsion and future fighter engines.One of its most advanced offshoots is the Kaveri Derivative Engine (KDE), also known as the dry Kaveri, which is being developed to power DRDO's Ghatak stealth unmanned combat aerial vehicle. Unlike the original fighter engine, the dry variant does not use an afterburner and is designed to generate around 49-51 kN of thrust. The engine has completed altitude testing in Russia and undergone extensive ground validation. According to GTRE, only limited flight testing remains before certification. Parallel work is also underway on an upgraded afterburning version, commonly referred to as Kaveri 2.0. While earlier versions were expected to produce around 75-79 kN of thrust, the latest full-afterburner trials witnessed by Defence Minister Rajnath Singh are aimed at increasing output to 81-83 kN, bringing the engine closer to the thrust class required for future combat aircraft.Technology developed under the programme has also resulted in the Kaveri Marine Gas Turbine (KMGT). The engine has been tested at the Naval Dockyard in Visakhapatnam, where it generated around 12 megawatts (approximately 16,000 horsepower) of propulsion power. Although less powerful than the 22 MW GE LM2500 gas turbines used on larger Indian Navy warships such as INS Vikrant and the Shivalik-class frigates, the KMGT has met the Navy's performance requirements and continues to undergo further validation.Why India still depends on GE enginesDespite decades of investment in indigenous engine development, India's frontline fighter fleet continues to rely heavily on engines supplied by US aerospace major GE Aerospace.The General Electric F404-IN20 powers the Tejas Mk-1 and Tejas Mk-1A, while the more powerful F414 has been selected for the Tejas Mk-2. The same engine family is also expected to power the first prototypes of the Advanced Medium Combat Aircraft (AMCA) until an indigenous engine becomes available. GE engines also power several other key Indian military platforms. The Indian Navy's P-8I long-range maritime patrol aircraft and MH-60R Seahawk helicopters use GE powerplants, while the Indian Air Force's AH-64E Apache attack helicopters are also equipped with GE engines. At sea, LM2500 marine gas turbines provide propulsion for INS Vikrant, the Shivalik-class stealth frigates and several other frontline warships.India's dependence extends beyond procurement to maintenance and lifecycle support. Earlier this year, GE Aerospace signed an agreement with the Indian Air Force to establish an in-country depot facility for the F404-IN20 engines powering the Tejas fleet. The facility will undertake repair and overhaul work within India, reducing turnaround times and dependence on overseas maintenance facilities.However, recent supply chain disruptions have highlighted the risks of relying on imported propulsion systems. Deliveries of F404 engines for the Tejas Mk-1A were delayed by more than a year, slowing aircraft production. HAL imposed contractual penalties on GE Aerospace for the delays, although the company has assured that deliveries will accelerate during 2026.For India, developing an indigenous fighter engine is therefore more than a technological milestone. It is a strategic necessity that would reduce dependence on foreign suppliers for one of the most critical components of a combat aircraft while strengthening operational autonomy and long-term defence preparedness.Link with the AMCA programmeThe renewed momentum behind the Kaveri programme coincides with India's plans to develop the fifth-generation Advanced Medium Combat Aircraft (AMCA), a project expected to shape the future of the Indian Air Force.The government has shortlisted three private-sector consortia to partner with the Aeronautical Development Agency (ADA) in building five AMCA prototypes under an initial allocation of Rs 15,000 crore. While the first prototypes are expected to fly with imported GE F414 engines, the long-term objective is to equip the fighter with an indigenous powerplant.To accelerate that effort, the government has launched the National Aero Engine Mission, which aims to bring together Indian industry, research institutions and foreign technology partners to develop a modern fighter engine. The initiative has opened the door for collaboration with countries such as France and the United Kingdom to bridge critical technology gaps in areas such as high-temperature materials, turbine blades, advanced manufacturing and engine design.During his visit to GTRE, Rajnath Singh welcomed such partnerships, saying they would help India understand technological challenges while strengthening domestic capability.Can Kaveri finally succeed?The original Kaveri engine is unlikely to power frontline Tejas fighters after being delinked from the programme in 2008. However, what began as an engine for a single aircraft has evolved into a broader national effort to master one of the world's most complex defence technologies.The programme has already yielded indigenous capabilities in metallurgy, compressor and turbine design, digital engine controls and testing infrastructure. Those technologies are now finding applications in the Kaveri Derivative Engine for the Ghatak UCAV, the Kaveri Marine Gas Turbine and the upgraded Kaveri 2.0 programme.The successful full-afterburner test witnessed by the defence minister, coupled with renewed government backing and the National Aero Engine Mission, has injected fresh momentum into India's long-standing ambition of developing an indigenous fighter engine. Even if Kaveri 2.0 does not directly power the AMCA, the knowledge and technologies generated through the programme are expected to contribute significantly to future indigenous propulsion systems.Whether India can field a fully indigenous fighter engine within the next decade remains uncertain. Yet, after more than three decades of setbacks, the Kaveri programme is increasingly being viewed not as a failed Tejas engine, but as the technological foundation for India's next generation of military aero engines and a critical step towards self-reliance in aerospace propulsion.