India’s defense modernization drive is entering a decisive new phase. Two separate but significant developments this month—one in the skies and the other beneath the seas—have underscored the country’s intent to cut its dependence on foreign technology while simultaneously projecting itself as a reliable partner in global security operations.
On the aviation front, the Gas Turbine Research Establishment (GTRE) has proposed a bold plan to convert two Sukhoi Su-30MKI fighter jets into flying testbeds for indigenous jet engines. Meanwhile, in the maritime domain, the Indian Navy has achieved its first-ever successful “mating” with foreign submarines during multinational submarine rescue drills in the South China Sea.
Taken together, these developments highlight India’s twin-track approach: strengthening its indigenous defense capabilities under the Atmanirbhar Bharat policy, while also showcasing its readiness to cooperate with international partners in critical security operations.
The GTRE proposal submitted to the Ministry of Defence marks a turning point in India’s quest for self-reliant aerospace capabilities. The establishment, which has long been at the heart of India’s aero-engine research, wants to modify two Indian Air Force (IAF) Su-30 MKIs to serve as airborne laboratories for testing indigenously developed engines and their components.
This initiative is designed to cut through one of the biggest hurdles in India’s defense technology ecosystem: the prolonged and uncertain path of engine certification.
“Flying testbeds allow us to collapse timelines that otherwise stretch over years in ground-based simulations and piecemeal validation,” said a senior DRDO official familiar with the proposal. “It bridges the gap between theoretical models and combat realities.”
The choice of the Su-30 MKI is deliberate. As the backbone of the IAF, with more than 260 aircraft in service, the twin-engine heavy fighter offers several advantages:
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Proven Airframe: Its robust structure is well-suited to handle experimental loads and stresses during test flights.
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Operational Familiarity: The IAF has two decades of deep experience flying and maintaining the jet, reducing the risks of handling untested components.
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Twin-Engine Safety Net: A modified engine can be tested while the second, unmodified engine provides redundancy in case of in-flight anomalies.
With specialized sensors, data loggers, and telemetry systems fitted onto the aircraft, GTRE engineers will gather real-time data on parameters like thrust, fuel burn, vibration, and thermal loads.
Currently, indigenous engine components go through long cycles of lab testing, rig trials, and limited ground runs before they can even be considered for flight trials. This creates a bottleneck that has slowed the development of advanced fighter engines, such as those intended for the Tejas Mk-2 and the Advanced Medium Combat Aircraft (AMCA)—India’s planned fifth-generation stealth fighter.
GTRE’s new approach introduces three innovations:
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Performance Mapping
Engineers will monitor thrust efficiency, heat tolerance, and fuel economy in real-time, comparing indigenous parts directly with foreign originals. -
Safety by Design
A detailed Failure Modes, Effects, and Criticality Analysis (FMECA) will be integrated into testing phases. This ensures potential design flaws are identified early, enhancing safety and reliability. -
Phased Clearances
Instead of waiting for an entire engine to be perfected, individual parts will be certified for limited operational use, with lifespans extended gradually as confidence builds.
“This staircase approach ensures faster deployment without compromising safety,” explained a defense aviation analyst. “It’s an agile model compared to the all-or-nothing certification process of the past.”
The timing of this proposal is strategic. With India’s defense import bill still among the world’s highest, the government has made indigenous engine development a top priority. Aero-engines are considered the “holy grail” of military aviation technology—one of the most difficult and closely guarded fields globally.
By taking testing airborne, India is signaling both confidence in its engineers and determination to close the technology gap with advanced aerospace nations. The Su-30 testbeds could cut years off the development cycle, accelerating readiness for the Tejas Mk-2 and AMCA programs.
Still, the initiative is not without risks. Safety of pilots during test flights, coordination between GTRE, Hindustan Aeronautics Limited (HAL), and the IAF, and the sheer cost of modifying frontline fighters remain challenges. But the potential payoff—strategic independence in propulsion technology—makes it a gamble worth taking.
While the skies saw plans for innovation, the seas witnessed achievement. The Indian Navy confirmed that it had successfully achieved its maiden “mating” with foreign submarines during the ongoing Exercise Pacific Reach 2025 (XPR-25) in the South China Sea.
In naval terms, “mating” refers to the docking of a rescue submersible with a distressed submarine, enabling transfer of personnel. Achieving this with foreign submarines during a multinational exercise is a major validation of India’s submarine rescue capability.
Hosted by Singapore since September 15, XPR-25 is one of the world’s largest submarine rescue drills, involving over 40 nations as participants or observers. The Indian Navy deployed its indigenously designed Diving Support Vessel INS Nistar, operating under the Eastern Fleet, to Changi port.
The vessel was inducted in 2023 specifically to enhance India’s underwater rescue and deep-sea diving capabilities. During the exercise, the Navy carried out three successful mating evolutions with foreign submarines, including remotely operated vehicle (ROV)-based operations.
“Indian Navy successfully achieved maiden mating with foreign submarines in South China Sea during ‘XPR-25,’ conducting the full spectrum of intervention and rescue operations,” said an official statement.
This achievement builds on India’s induction of two Deep Submergence Rescue Vehicles (DSRVs) in 2018–19, one on each coast. These systems allow rescue operations up to depths of 650 meters, placing India in a select group of navies with such capability.
“The milestone underscores our readiness, interoperability, and commitment to global submarine rescue, proving India as a dependable maritime partner and proactive contributor to regional safety.”
For India, the exercise goes beyond humanitarian commitments. It demonstrates to partners and rivals alike that India is steadily building niche naval capabilities, essential for credibility in the Indo-Pacific’s increasingly contested waters.
These two developments—GTRE’s flying testbed initiative and the Navy’s submarine rescue milestone—might seem unrelated at first glance. But together, they illustrate the dual trajectory of India’s defense modernization strategy:
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Indigenization and Self-Reliance
By pushing for indigenous aero-engine testing, India is taking a bold step toward cutting free from dependence on Russian, American, and French propulsion systems. A successful indigenous engine would dramatically increase strategic autonomy. -
Global Cooperation and Credibility
By joining multinational submarine rescue drills and proving operational effectiveness, India reassures partners that it is not an insular power but a reliable player in global security frameworks.
The interplay of self-reliance and international cooperation defines India’s emerging role.
Both initiatives, however, face formidable hurdles.
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For GTRE’s Testbeds:
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Technical complexities of integrating unproven hardware into frontline fighters.
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Ensuring flight safety for test pilots.
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Sustaining funding and political support through inevitable setbacks.
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For the Navy’s Submarine Rescue Ambitions:
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Maintaining the high readiness levels of DSRVs and support vessels.
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Continuous training with diverse submarine classes across navies.
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Balancing humanitarian commitments with operational secrecy in sensitive waters.
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India’s defense establishment is clearly signaling urgency. Whether in the skies or under the seas, the message is consistent: India is determined to master critical technologies at home while contributing responsibly to global security abroad.
If GTRE’s Su-30 testbeds succeed, they could redefine the future of Indian combat aviation. If the Navy continues to expand its submarine rescue capabilities, it cements India’s place among the world’s leading maritime powers.
