Systemic Failures in India’s Indigenous Fighter Engine Development

 A Critical Assessment of GTRE’s Kaveri Program

The development of a modern fighter-class turbofan engine represents one of the most technologically demanding undertakings in aerospace engineering. It requires mastery over high-temperature metallurgy, advanced aerothermodynamics, precision manufacturing, control systems integration, long-duration reliability validation, and a deeply integrated industrial ecosystem. Over the past several decades, India’s principal institutional vehicle for achieving this capability has been the Gas Turbine Research Establishment (GTRE), a laboratory under the Defence Research and Development Organisation (DRDO).

The most ambitious expression of this mandate was the GTX-35VS Kaveri engine program, launched in 1989 to power the Light Combat Aircraft, later known as the HAL Tejas. The program was intended to deliver a fully indigenous, afterburning turbofan capable of producing approximately 52 kN of dry thrust and 81–90 kN of wet thrust. After nearly four decades of effort, the engine failed to qualify for fighter service and was delinked from the Tejas program. The consequences were strategic: India’s indigenous fighter entered service powered by foreign engines.

While aero-engine development is universally complex and often prolonged, the Kaveri experience reveals not merely technical difficulty but a pattern of systemic failure. These failures spanned thermodynamic design assumptions, materials capability, governance structure, infrastructure readiness, and ecosystem integration. By 2021, the program had expended over ₹20 billion (equivalent to ₹50 billion in 2023), with only partial milestones met.

The Core Technical Problem: Failure to Achieve Rated Dry Thrust

The Kaveri engine's primary technical failure centres on its inability to consistently achieve targeted dry thrust levels across the full operational envelope, a critical measure of core integrity. Dry thrust, generated without afterburner, hinges on the efficient integration of compressor, combustor, and turbine stages, encompassing airflow management (designed at 78 kg/s), pressure ratios (21.5:1 overall), and thermal tolerances.

Despite efforts, the engine attained only 48.5–51 kN in dry thrust during high-altitude tests by 2022—below the 52 kN design goal—and fell short of the 83–85 kN wet thrust required for advanced Tejas variants. As DRDO Chairman Samir V. Kamat noted in 2025, while the engine performs adequately at 72 kN wet thrust, it lacks the scalability for Tejas integration.

Analyses, including the 2011 Comptroller and Auditor General (CAG) report, identified key deficiencies: inefficiencies in compressor stages (featuring transonic blading in low-pressure sections and variable inlet guide vanes in high-pressure), constraints on turbine inlet temperature (TIT ≈1,427°C) due to material limitations, and airflow mismatches. Absent advanced single-crystal superalloy turbine blades with internal cooling channels and thermal barrier coatings, the thermodynamic cycle was inherently restricted, necessitating derating to avert creep, thermal fatigue, and structural failure.

This underperformance arose from an overly ambitious cycle design that surpassed India's domestic materials and manufacturing capabilities at the time. Repeated turbine blade failures in the early 2000s prompted imports from France's Snecma (now Safran), underscoring the gap. Fundamentally, dry thrust shortfalls—not merely afterburning deficits—exposed core-level flaws in compressor efficiency, achievable TIT, and integration, as thermodynamic aspirations outpaced available ecosystem support.

Ambition–Capability Mismatch in Cycle Design

The Kaveri was conceived as a near fourth-generation class engine in a country without prior operational turbofan production experience. Its targeted pressure ratios and temperature regimes required advanced single-crystal turbine blades, sophisticated internal cooling passages, and high-precision casting technologies.

India did not possess a mature ecosystem for single-crystal superalloys during critical development phases. Without this capability, sustained high-temperature operation at design limits becomes structurally unviable. Turbine blades experience creep, thermal fatigue, and life-cycle instability. As a result, TIT must be reduced, which in turn lowers thrust.

This created a structural contradiction: the engine’s design cycle demanded performance levels that the industrial base could not yet support. Instead of recalibrating ambition to ecosystem readiness, the program attempted incremental fixes within an over-ambitious architecture.

Weight Growth and Performance Degradation

As development progressed, the engine reportedly gained weight relative to its original targets. Weight growth in turbofan programs typically reflects structural reinforcement, redesign for stress tolerance, or compensatory adjustments to address performance shortfalls.

An increase in mass reduces thrust-to-weight ratio and further constrains fighter integration viability. In high-performance aircraft, propulsion margins are unforgiving. Even moderate weight escalation can render an engine noncompetitive.

This weight spiral was not merely a numerical inconvenience; it was symptomatic of deeper, unresolved engineering trade-offs.

Altitude Testing and Operational Envelope Collapse

A pivotal moment in the Kaveri program occurred during high-altitude testing conducted abroad in the early 2000s. These tests revealed that the engine could not consistently demonstrate stable performance across the required operational envelope.

Altitude testing exposes surge margin deficiencies, airflow instability, temperature stress behaviour, and transient response weaknesses. Failures at this stage indicate that laboratory-level validation had not translated into flight-representative robustness.

Following these setbacks, the engine was removed from the Tejas integration roadmap. That decision marked the effective termination of its fighter role.

Governance and Systems Engineering Deficiencies

Technical challenges alone do not fully explain the program’s outcome. Several systemic governance weaknesses appear to have compounded the engineering problems.

First, there were reports that external consultants and international experts raised concerns about core sizing, achievable pressure ratios, and realistic temperature limits. Allegations persist that more radical redesign options were not adopted decisively when these warnings emerged. In complex aerospace programs, early architectural reset is often painful but necessary. Delayed course correction can lock a project into incremental compromise rather than structural resolution.

Second, the design freeze discipline appears to have been weak. The Tejas airframe itself evolved over time, gaining weight and altering performance demands. Instead of resetting the propulsion architecture to match revised aircraft requirements, the engine program continued along its established trajectory. Requirement drift layered complexity onto an already stressed design.

Third, the institutional structure under which GTRE operated was oriented toward research and prototype development rather than industrial-scale certification and reliability growth. Fighter engines require not only technological innovation but thousands of hours of endurance validation, statistical reliability tracking, and production engineering culture. That industrial maturity was not fully aligned with program ambition.

Infrastructure and Ecosystem Constraints

At the time of critical development phases, India lacked comprehensive indigenous high-altitude test facilities and long-duration endurance test cells for fighter-class engines. Reliance on foreign testing infrastructure meant that key performance truths emerged late in the program lifecycle.

Equally significant was the limited integration of private-sector metallurgy, precision manufacturing, and advanced coating technologies. A fighter turbofan is not the product of a single laboratory; it is the output of a coordinated industrial ecosystem. That ecosystem was still embryonic during Kaveri’s formative years.

Moreover, coordination between designer (GTRE), manufacturer (HAL), and end user (Indian Air Force) appears to have lacked the tight iterative feedback mechanisms seen in established engine houses. Effective propulsion development requires continuous user-informed refinement.

Strategic Consequences

The delinking of the Kaveri engine from the Tejas program had significant strategic consequences. Tejas entered service with GE engines under contracts exceeding $105 million in 2004, reinforcing foreign propulsion dependence and increasing cost and schedule exposure. The move also affected DRDO’s propulsion credibility, with implications for future ambitions such as the AMCA, where engine autonomy is critical.

However, the program yielded technological spin-offs. A dry-thrust Kaveri Derivative Engine (48–50 kN) is being positioned for the Ghatak UCAV, while a 12 MW marine variant (KMGT) has been explored for naval use. Industrial partnerships, including with BHEL, and advances in combustor technology, indigenous FADEC (KADECU), and metallurgy have strengthened technical foundations for future efforts, including a potential 75–79 kN “Kaveri 2.0.”

Despite these gains, India has yet to field an operational indigenous fighter-class turbofan, leaving the original strategic objective unfulfilled.

Inference

The Kaveri program did not fail simply because aero-engines are difficult to build. It failed because systemic misalignments were never fully corrected.

1) Thermodynamic ambition exceeded material capability.

2) Cycle design was not recalibrated when ecosystem constraints became evident.

3) Dry thrust shortfalls exposed core-level limitations.

4) Altitude testing revealed operational fragility.

5) Governance mechanisms did not enforce early architectural reset.

6) Infrastructure lagged performance targets.

Taken together, these factors constitute a systemic failure rather than an isolated technical setback.

GTRE did build valuable knowledge in gas turbine science, combustor design, and control systems. However, the central strategic mandate—to deliver a certified indigenous fighter turbofan—remains unmet.

If future propulsion programs are to succeed, ambition must be synchronised with industrial readiness, design governance must enforce hard reset decisions when required, and ecosystem development must precede rather than follow thermodynamic aspiration.

Only then can propulsion sovereignty move from aspiration to operational reality.

Navigating the HAL Crossroads: A 2026 Pivot from Dominance to Adaptation

 In the dynamic world of aerospace, Hindustan Aeronautics Limited (HAL), India's venerable state-owned powerhouse, stands at a pivotal juncture as we enter 2026. Boasting a market capitalisation of around ₹2.7-2.9 lakh crore—roughly $32-35 billion USD—HAL holds its ground as one of the globe's top aircraft manufacturers, often ranked fourth behind titans like Airbus, Boeing, and Lockheed Martin. This financial stature is commendable, yet it conceals underlying challenges that demand attention. As a cornerstone of India's defence landscape, HAL is finding itself gradually edged out of marquee initiatives such as the Advanced Medium Combat Aircraft (AMCA) due to persistent delays, technological hurdles, and operational inefficiencies. The emerging emphasis on private sector collaboration marks a welcome shift away from HAL's long-held monopoly, encouraging the company to evolve and secure its place in a rapidly changing industry it has long shaped.

Unpacking HAL's Challenges: Reflections on a Legacy of Caution

For more than two decades, HAL has thrived under the umbrella of government-backed exclusivity in India's aerospace arena, drawing on lucrative contracts and international technology-sharing pacts. Founded in 1940 and reorganised in 1964 via the fusion of Hindustan Aircraft Ltd. and Aeronautics India Ltd., HAL has traditionally excelled in licensed manufacturing over bold, homegrown innovation. This has earned it the unfortunate moniker of a "garage for foreign jets," where it assembles models like the MiG-21, Su-30MKI, BAE Hawk and Jaguar without fully ascending to the ranks of a holistic design innovator.

The Challenge of Technology Integration

HAL's collaborations with overseas original equipment manufacturers (OEMs) were meant to foster deep technological uptake, but the results have fallen short of expectations. The Su-30MKI initiative, launched in the late 1990s, saw HAL produce 272 units at its Nasik plant under license from Russia's Sukhoi. Likewise, the Jaguar program from the 1980s yielded over 125 aircraft, many still operational after enhancements. Regrettably, these ventures were approached more as routine assembly lines than gateways to mastering essential technologies such as "hot-core" engines or cutting-edge avionics.

This measured pace contrasts sharply with the strides made by China's Aviation Industry Corporation of China (AVIC). In a similar timeframe, AVIC has pursued foreign know-how with Vigour through partnerships, joint ventures, and robust domestic R&D, leaping from mere licensed builds to pioneering fifth-generation fighters like the J-20. China's approach, bolstered by targeted supply chain investments and supportive policies, has positioned it as a global contender. India, by comparison, continues to rely on imported components, which underscores ongoing vulnerabilities in its defence infrastructure.

The Gap in Operational Urgency

Further straining stakeholder trust are HAL's execution setbacks. In early 2025, during Aero India, the Indian Air Force Chief voiced a lack of confidence in HAL, pointing to recurring postponements and an absence of "mission mode" intensity. This spotlighted the Tejas Light Combat Aircraft (LCA) Mk1A, whose timelines were extended by two years in February 2026. Currently, just five Mk1A units are delivery-ready, with nine others pending General Electric (GE) engines. The IAF has observed that HAL's commitments to timelines and standards are sometimes not met, intensifying concerns over fleet readiness.

These reflect HAL's wider hurdles, including an order backlog surpassing ₹2.7 lakh crore, institutional sluggishness, and R&D spending that trails international benchmarks.

A Comparative Lens: HAL and AVIC in Focus

In aerospace and defence, HAL and AVIC embody their countries' ambitions for self-sufficient military and civil aviation. While both advance national goals, AVIC's swift rise and expansive footprint highlight differences rooted in policy, funding, and heritage.

HAL has progressed from basic assembly to elements of indigenous creation over the years, yet it grapples with critiques over its gradual path to complete design independence. AVIC, established in 1951 and restructured in 2008 after earlier divisions, has optimised its structure to spark innovation. Building on Soviet foundations, it has chased technology transfers aggressively via joint ventures, morphing from replicating Russian models to crafting sophisticated systems.

AVIC exemplifies "technological leapfrogging," commanding expertise in hot-core engines, advanced avionics, and composites through intensive R&D and acquisitions like Continental Motors (2010) and Cirrus (2011). With over 30 aviation labs and alliances with Honeywell, GE, and Safran, AVIC advanced from MiG derivatives to native fifth-generation tech in mere decades, fuelled by substantial state support.

HAL, though engaged in similar partnerships (Su-30MKI, Jaguar), has been seen as a "laggard" for viewing them primarily as production exercises rather than absorption catalysts. It trails in engine development, depending on GE F414 and Safran agreements, and contends with delays like those in Tejas Mk1A. Encouragingly, HAL is adopting platform-based accountability as advised by the Boston Consulting Group (BCG) and pursuing authentic tech transfers for AMCA engines (100% IP via Safran). Nonetheless, bureaucratic hurdles and contract dependency have somewhat sidelined it from leading roles.

The Ripple Effects: Exclusion from the AMCA Spotlight

HAL's accumulated issues peaked with its de facto sidelining from the AMCA's primary stewardship in February 2026.

The Basis for Disqualification

The Aeronautical Development Agency (ADA) highlighted HAL's outsized order book—exceeding three times its yearly revenue—and a track record of timeline slips as reasons it posed risks to this flagship endeavour. This mirrors the protracted 30-year Tejas journey, which ADA is keen to sidestep.

Embracing Private Sector Dynamism

To hasten AMCA progress, the government has channelled the project into a Special Purpose Vehicle (SPV) spearheaded by private entities. From seven contenders, three consortia advanced: Tata Advanced Systems Limited (TASL), Larsen & Toubro (L&T) alongside Bharat Electronics, and Bharat Forge teamed with BEML and Data Patterns. These groups will oversee prototype building and mass production, targeting the initial prototype in 3-4 years. HAL retains a possible contributory position but steps back from the helm.

This move underscores a policy tilt toward private agility, echoed in recent online dialogues on platforms like X, which underscore HAL's delays and the value of competitive edges.

Charting a Resilient Future: HAL's Transformative Steps

To navigate this shift, HAL is embracing essential changes, propelled by both outside influences and internal resolve.

1. Platform-Based Accountability: Guided by BCG insights, HAL is pivoting from regional setups to Platform Business Units by March 2026. This empowers managers with direct responsibility for aircraft schedules, fostering greater efficiency and punctuality.

2. Authentic Technology Adoption: New pacts prioritise meaningful integration. The GE-F414 deal, with 80% technology transfer, will energise Tejas Mk2 and early AMCA models, eyeing the first home-built engine by 2029. Safran's collaboration on a 120 kN AMCA engine grants 100% IP rights and complete transfer, enlisting private firms as oversight partners.

3. Evolving to a Key Supplier: HAL may transition from chief integrator to a premier component provider for domestic alliances and international leaders like Boeing and Airbus. This strategy plays to its fabrication strengths while alleviating full-project oversight demands.

Closing Thoughts

HAL is evolving beyond being the sole player in the field. The AMCA SPV's emergence, alongside private innovators, signals the close of an era of unchallenged state dominance. To thrive, HAL must demonstrate parity with private-sector nimbleness, lest it settle into a subcontractor niche in the sector it pioneered. As India advances self-reliance through Atmanirbhar Bharat, this transition holds promise for sparking widespread creativity—provided HAL seizes the moment for true reinvention. Meanwhile, AVIC's expansive vision and ingenuity cement its status as a global frontrunner, offering India valuable insights from China's proactive tech integration model, even as HAL carves its path as an essential, India-centric contributor.

Author: GR Mohan

VIP Charter Operations, and the Regulatory Blind Spot in Indian Aviation

 On the morning of 28 January 2026, Maharashtra Deputy Chief Minister Ajit Pawar was killed when a Learjet 45XR chartered from VSR Aviation crashed during its approach to Baramati Airport. The accident claimed the lives of all on board, including Captain Sumit Kapoor and First Officer Shambhavi Pathak. Within hours, the nation mourned. Within days, the familiar script began to unfold: speculation, selective leaks, and an unspoken but inevitable question—what did the pilots do wrong?

That question, while emotionally satisfying, is dangerously incomplete.

Because Baramati was not merely an aviation mishap. It was the foreseeable outcome of systemic regulatory neglect in India’s non-scheduled and VIP charter operations—a failure repeated often enough that it can no longer be dismissed as a coincidence.

This tragedy joins a grim list: Madhavrao Scindia, G.M.C. Balayogi, Y.S. Rajasekhara Reddy, and General Bipin Rawat. Different aircraft, different years, different circumstances—but a disturbingly consistent pattern. Each accident prompted solemn assurances and official inquiries. Yet two decades on, the structural weaknesses that imperil VIP aviation remain stubbornly intact.

A High-Consequence Flight Into a Low-Capability Airport

Baramati Airport is a Visual Flight Rules (VFR) aerodrome, primarily used for flying training. It has no instrument approach procedures, no permanently manned Air Traffic Control tower, and no on-site meteorological office. Pilots operating there receive landing advisories, not clearances, and are required to maintain continuous visual contact with the runway environment.

None of this is inherently unsafe if operations are strictly limited to suitable conditions.

Under DGCA Civil Aviation Requirements (CARs) governing VFR and all-weather operations, flights into such aerodromes are permitted only when prescribed visibility minima—typically 5 km or more—are met. Post-accident reporting consistently pointed to poor visibility at the time of the approach. Some media outlets loosely invoked “dense fog,” a term more dramatic than technical. The real issue was simpler and more troubling: conditions were marginal or unsuitable for VFR operations into a non-instrument airfield.

The most revealing detail came after the crash. The Indian Air Force swiftly deployed ATC and meteorological personnel to Baramati to support ongoing operations. This was operationally prudent—but symbolically damning. It tacitly acknowledged that the level of air traffic and weather support required for safety was absent until lives were lost.

In aviation, safety measures introduced after an accident are not solutions. They are confessions.

The Seduction of Pilot Blame

Every air crash eventually finds its way to the cockpit. The pilots were there. They made the final call. End of story.

Except it never is.

Aviation accidents rarely result from a single bad decision. They emerge from pressure, context, and constrained choices. To isolate the pilot’s judgment while ignoring the forces shaping that judgment is not analysis—it is abdication.

Consider a simple root-cause chain:

a) Why did the aircraft attempt a landing in marginal weather?
Because the flight needed to be completed.

b) Why did completion feel non-negotiable?
Because VIP schedules allow little tolerance for delay or diversion.

c) Why does that pressure weigh more heavily on charter pilots?
Non-scheduled operations offer weaker institutional protection than airlines.

d) Why is there no effective counterweight to that pressure?
Because regulatory oversight of non-scheduled operators is lighter and less risk-based.

e) Why has this imbalance persisted?
Because the system has normalised elevated risk for VIP mobility—until tragedy intervenes.

This is not about bravado or heroics. It is about structural coercion, where pilots are left to absorb competing demands from passengers, employers, and circumstances—while the regulator remains largely invisible until after the fact.

What the Rulebook Actually Says—and What Happens in Practice

India is not short of aviation regulations. The problem is how selectively they are applied.

DGCA’s CAR on All-Weather Operations clearly requires that flights be conducted only when weather conditions meet prescribed minima, and that approaches be discontinued when visual reference is inadequate. ICAO Annexe 6, which India is bound to follow, reinforces the obligation on states to ensure operators maintain operational control systems that prevent unsafe continuation of flight.

Yet in practice, VIP charter operations are allowed to proceed into VFR-only aerodromes without additional safeguards, even when conditions deteriorate.

Similarly, DGCA CARs on aerodrome operations require that facilities and services be commensurate with the nature of operations. ICAO Annexe 11 (Air Traffic Services) and Annexe 3 (Meteorology) emphasise the provision of ATS and weather information necessary for safety “to the extent practicable.”

The question writes itself: If ATC and meteorological support become “practicable” immediately after a fatal crash, why were they not required beforehand for high-consequence VIP flights?

The Pressure Nobody Wants to Name

DGCA regulations are unambiguous on paper: the Pilot-in-Command has absolute authority, and operators must ensure that pilots are not coerced into unsafe decisions.

But authority without insulation is an illusion.

In scheduled airlines, pilots operate within a robust ecosystem—dispatch departments, independent weather assessments, formal diversion protocols, fatigue risk management systems, and just-culture protections. In many non-scheduled operations, especially those carrying VIPs, these buffers are thinner or absent altogether.

ICAO Annexe 19 on Safety Management explicitly recognises the danger of organisational pressure and mandates Safety Management Systems that address it. Yet non-scheduled operators are not held to the same SMS maturity as airlines, despite operating flights where the political, social, and reputational stakes are far higher.

When a VIP charter pilot diverts, the cost is not just fuel and time. It is embarrassment, political inconvenience, and potential loss of future business. The pressure may never be spoken—but it is always understood.

Investigations Without Reform

India’s Aircraft Accident Investigation Bureau (AAIB) operates under rules aligned with ICAO Annexe 13, which emphasises accident prevention over blame. Yet history suggests that investigations into VIP crashes rarely translate into visible systemic reform.

Findings are delayed. Reports are opaque. Recommendations—if issued—fade quietly into administrative files. Meanwhile, the operational environment that enabled the accident remains largely unchanged.

This investigative culture does not just fail the public. It fails the next crew.

The Real Blind Spot: Non-Scheduled Operations

The most uncomfortable truth is this: India regulates its highest-consequence flights with lower safety margins than its routine airline operations.

Non-Scheduled Operator Permit (NSOP) holders are granted operational flexibility that was meant to encourage connectivity and enterprise. Over time, that flexibility has hardened into leniency—without a corresponding risk-based oversight framework.

ICAO’s philosophy is explicit: regulation must be proportionate to risk, not category. A flight carrying a chief minister into a marginal airfield in winter conditions is not “less risky” because it is non-scheduled. It is more risky—and should be treated as such.

What Meaningful Reform Would Look Like

This tragedy did not occur because India lacks rules. It occurred because rules were not aligned with reality.

Real reform would include:

a) Risk-based restrictions on VIP flights into VFR-only aerodromes

b) Mandatory independent weather assessment and diversion authority

c) Airline-equivalent SMS requirements for charter operators conducting VIP flights

d) Transparent AAIB investigations with enforceable follow-up mechanisms

VIPs do not need privileges in the air. They need higher safety margins.

Until regulators accept that truth, India will continue to cycle through grief, blame, and forgetfulness—each time promising lessons learned, and each time leaving the system largely untouched.

Aviation safety advances, as history grimly reminds us, only when tragedy is met with honest accountability rather than convenient scapegoating. Baramati deserves nothing less.

Author: GR Mohan

The 2025 IndiGo Flight Disruption Crisis

 Regulatory Non-Compliance, Systemic Failures, and the Case for Smarter Fatigue Risk Management

In December 2025, India’s aviation system went through one of its most disruptive operational episodes in recent memory. IndiGo Airlines—by far the country’s largest carrier, with roughly 60 per cent of the domestic market—was forced to cancel thousands of flights over a matter of days. What initially appeared to be a mix of weather issues, congestion, and technical glitches soon revealed a more fundamental problem: the airline was unable to operate its published schedule while complying with the revised Flight Duty Time Limitation (FDTL) regulations issued by the Directorate General of Civil Aviation (DGCA).

These revised FDTL norms were introduced specifically to address long-standing concerns around pilot fatigue, a recognised safety risk globally. The rules were rolled out in two phases during 2025, with the second and more restrictive phase coming into effect on 1 November 2025. Within weeks, the cracks began to show. By early December—right in the middle of peak winter travel and the wedding season—IndiGo’s operation started to unravel, leaving passengers stranded and triggering intense scrutiny of airline management decisions as well as regulatory preparedness.

This article looks beyond the headlines to examine what really went wrong. It analyses IndiGo’s internal planning and execution failures, evaluates the DGCA’s regulatory framework and oversight approach, and explores whether India now needs to move beyond purely prescriptive duty limits toward a more mature Fatigue Risk Management System (FRMS). Drawing on DGCA circulars, audit findings, and industry commentary, the discussion asks a central question: was this crisis caused by rigid regulation—or by inadequate preparation and execution at the airline level?

Background: DGCA’s Revised FDTL Framework

The DGCA formally notified revised FDTL requirements in January 2024 through an updated Civil Aviation Requirement (CAR). The intent was clear: bring India’s fatigue regulations closer to international best practices and address chronic concerns around extended duty periods, night operations, and cumulative fatigue.

To allow airlines time to adjust, implementation was deliberately phased:

a) Phase 1 (effective 1 July 2025):
Weekly rest requirements increased from 36 hours to 48 hours.

b) Phase 2 (effective 1 November 2025):
Tighter controls on night operations, a sharp reduction in permitted night landings (from six to two per week), and more restrictive duty-hour limits.

The framework set clear, prescriptive limits for Flight Duty Period (FDP), Flight Time (FT), and minimum rest, with additional provisions covering acclimatisation, split duty, standby, and unforeseen operational disruptions. Airlines were required to submit revised FDTL compliance schemes for DGCA approval. While initial compliance deadlines were set for 2024, extensions pushed full implementation into 2025.

There was little ambiguity in regulatory intent. The changes were known more than a year in advance, giving operators time to adjust hiring plans, training pipelines, and rostering models. That said, IndiGo’s high-frequency, tightly optimised network meant that even small planning errors carried outsized operational consequences.

Operational Timeline and Impact

Once Phase 2 came into force, the situation deteriorated quickly:

Period	Flight Cancellations	On-Time Performance
November 2025	1,232	67.7%
1–2 December	Escalating	49.5%, 35%
3–4 December	200–550 per day	19.7%, 8.5%
5 December	~1,600 (peak)	Severely degraded
Mid-December (cumulative)	~4,500	—

The knock-on effects were significant. Passenger disruption was widespread, refund liabilities were estimated at over ₹5 billion (around USD 59 million), and airfares on competing airlines surged. IndiGo’s market capitalisation reportedly dropped by nearly ₹400 billion (USD 4.7 billion). Indian Railways even had to add extra services to accommodate displaced travellers—an unusual but telling indicator of the system's overall impact.

What Went Wrong: A Closer Look

1. Planning and Manpower Management Failures

IndiGo initially pointed to weather, congestion, and technology issues. While these factors always play a role, they did not explain the scale or persistence of the disruption. Subsequent audits and industry analysis pointed to more basic problems: inadequate anticipation of the operational impact of Phase 2 FDTL rules, despite ample advance notice.

Fleet growth continued aggressively, but pilot recruitment, training, and rostering did not keep pace with the more restrictive duty and rest limits. Industry observers highlighted lean manpower assumptions, delayed hiring cycles, and heavy reliance on maximising crew productivity. Informal non-poaching practices were also cited as limiting short-term workforce flexibility.

DGCA audits found that IndiGo’s overall pilot numbers were not dramatically out of line with global benchmarks. The real weakness lay in rostering and utilisation. Poor scheduling decisions led crews to violate FDTL, triggering cancellations. IndiGo later acknowledged that it had underestimated the operational impact of Phase 2 implementation.

2. Lack of Contingency and Risk Mitigation Planning

Equally damaging was the absence of proactive mitigation. IndiGo did not meaningfully flag compliance risks to the regulator in advance, nor did it sufficiently trim schedules before enforcement began. Other Indian carriers, facing the same regulatory environment, made targeted capacity reductions and adjusted rosters early, avoiding widespread disruption.

Reports from pilots suggested that available crews were not always deployed effectively, pointing to coordination and planning issues rather than absolute shortages. In a high-utilisation, point-to-point network like IndiGo’s, even small inefficiencies cascaded rapidly into system-wide failure.

3. Regulatory Oversight Constraints

The DGCA was not immune from criticism. Questions were raised about the timing of enforcement actions and the effectiveness of oversight, particularly after the removal of four inspectors during the period. However, the regulator maintained that airlines had sufficient notice and flexibility, and that responsibility for implementation lay squarely with operators.

Regulatory Response

As the crisis peaked, the DGCA stepped in with a temporary, conditional exemption from certain FDTL provisions, valid until 10 February 2026. The relief was tied to periodic reviews and a structured compliance roadmap.

Enforcement actions included:

a) A record penalty of ₹22.2 crore (approximately USD 2.6 million) for 68 days of non-compliance

b) A requirement for financial guarantees

c) A mandated 10 per cent reduction in scheduled capacity

IndiGo is committed to restoring full operations by the end of the exemption period, citing improved pilot availability and revised rostering practices.

Why FRMS Now Matters

The disruption highlighted a long-standing issue: purely prescriptive duty-time rules, while essential, have limits—especially for large, complex airline operations. Recognising this, the DGCA released draft Fatigue Risk Management System (FRMS) guidelines in September 2025.

FRMS shifts fatigue management from fixed limits alone to a data-driven, performance-based approach. Core elements include:

a) Systematic identification of fatigue hazards

b) Continuous monitoring using operational and physiological data

c) Evidence-based mitigation strategies

d) Integration with existing Safety Management Systems (SMS)

Done properly, FRMS can offer flexibility without compromising safety. But it is not a shortcut. It requires strong data capability, scientific validation, regulatory maturity, and genuine organisational commitment. Pilot unions have rightly cautioned against FRMS being used as a backdoor to longer duties without safeguards, underscoring the need for transparency and independent oversight. 

Way Forward

The 2025 IndiGo disruption was not caused by unrealistic regulation. It was largely the result of management-level failures in planning, risk assessment, and execution. The DGCA provided sufficient lead time, and other airlines demonstrated that compliance was achievable with disciplined preparation.

That said, the episode offers clear lessons. Airlines must treat regulatory transitions as major operational risks, not administrative exercises. Regulators must strengthen oversight and enforcement consistency. And the industry as a whole must move toward more mature, evidence-based fatigue management through carefully implemented FRMS.

If Indian aviation is to grow sustainably without repeating crises of this scale, fatigue management must evolve from box-ticking compliance to a genuine safety culture—one built on data, transparency, and collaboration between regulators, operators, and pilots alike.

 

Disclaimer: The views expressed by the author are his personal interpretation of the events.

Author: GR Mohan

Aviation Accident Investigation in India: Transparency, Capability, and Accountability

 Over the past two decades, India has witnessed several serious aviation accidents. Yet, in many cases, the findings of these investigations have either not been published in a timely manner or have been released with limited substantive detail. This persistent opacity raises a fundamental question: is the absence of accessible investigative outcomes a result of deliberate institutional reticence, or does it reflect systemic apathy within the regulatory framework?

The most recent and widely publicised example is the Air India Boeing 787 Dreamliner accident during take-off at Ahmedabad. Despite the passage of several months since the occurrence, there has been little meaningful clarity regarding causal factors. The Aircraft Accident Investigation Bureau (AAIB), which has been tasked with the investigation, is structured primarily as a technical body. While technical competence is indispensable, effective accident investigation—particularly for complex airline operations—demands deep expertise in operational decision-making, human factors, organisational culture, and systemic risk management. In these domains, the AAIB’s capabilities appear limited.

A preliminary report was released in compliance with ICAO Annex 13 requirements. However, the document contained minimal analytical depth and offered little insight into the sequence of events or contributory factors. Rather than providing clarity, the report generated further uncertainty, prompting multiple stakeholders to seek judicial intervention to compel clarification of its contents. These proceedings have been repeatedly adjourned, largely due to the Civil Aviation Ministry’s failure to submit information requested by the court, reinforcing perceptions of deliberate non-cooperation.

ICAO-Mandated Timelines and International Practice

Internationally, aviation accident investigation follows clearly defined timelines intended to balance timeliness with analytical rigour:

a) Initial Notification: Operators must notify the relevant authorities (DGCA and AAIB in India) within 24 hours of an accident or serious incident.

b) Preliminary Report: As per ICAO Annex 13, the State of Occurrence must submit a preliminary report to ICAO within 30 days.

c) Final Report (Target): ICAO guidance recommends publication of the final report within 12 months.

d) Interim Statement: If the final report is not ready within 12 months, an interim statement outlining progress must be issued on the anniversary of the accident.

e) Complex Investigations: In particularly complex cases—such as those involving extensive wreckage damage or intricate system interactions—investigations may extend to 18–24 months. Agencies such as the U.S. National Transportation Safety Board (NTSB) routinely provide periodic updates during this period.

These timelines are designed not merely for procedural compliance but to ensure that safety lessons are identified and disseminated without undue delay.

Disclosure Restrictions and Misinterpretation

Indian regulations and international standards both restrict the public disclosure of certain sensitive materials. Rule 17(5) of the Aircraft (Investigation of Accidents and Incidents) Rules, 2025 explicitly prohibits the release of cockpit voice recordings and airborne image recordings. This mirrors ICAO Annex 13, Appendix 2, which requires States to ensure non-disclosure of such material to protect the integrity of investigations and the privacy of flight crews.

However, the legitimate need for confidentiality should not be conflated with an absence of analytical transparency. While raw audio or video data must remain protected, investigative authorities are still expected to clearly articulate factual findings, validated hypotheses, and emerging safety concerns.

Vacuum of Information and the Rise of Speculation

The lack of substantive detail in the preliminary report created an information vacuum that was rapidly filled by speculation. A proliferation of self-styled aviation experts advanced unverified theories, often through monetised podcasts and websites, prioritising sensationalism over evidence-based analysis. Rather than being countered by authoritative updates, these narratives were allowed to flourish, as the AAIB maintained a prolonged and conspicuous silence.

Simultaneously, professional pilot associations appeared primarily focused on pre-emptively deflecting any attribution of blame to the flight crew. This defensive posture escalated into opposition to investigative steps such as calling witnesses who might provide insight into crew decision-making, psychological stressors, or organisational pressures. Such resistance runs counter to modern safety science, which emphasises understanding—not assigning blame for—human performance within complex systems.

Absence of International Signals

Equally noteworthy is the absence of any public concern or technical advisories from international stakeholders involved in the investigation, including the FAA, the aircraft manufacturer (OEM), and the NTSB. Given the global fleet size of the Boeing 787, even preliminary indications of a systemic technical issue would normally trigger wider scrutiny, operational advisories, or interim safety recommendations. No such signals have emerged, and the aircraft continues to operate worldwide without design-related restrictions—suggesting that, at least thus far, no compelling evidence of a fundamental technical flaw has been identified.

Contrast with International Investigative Transparency

A comparison with international investigative practice is instructive. In the recent mid-air collision over the Potomac River involving a U.S. military helicopter and a commercial airliner, the NTSB issued multiple press briefings and investigative updates. These communications went beyond identifying proximate causes and examined deeper systemic failures, including airspace design, inter-agency coordination, and procedural oversight.

Similarly, following the UPS MD-11 crash during take-off, the NTSB released detailed interim findings that progressively built a comprehensive understanding of both technical and organisational contributors. Such openness has been conspicuously absent in comparable Indian investigations.

Systemic Issues and Normalisation of Deviance

On 12 January 2026, a U.S.-based aviation safety foundation presented findings to the U.S. Senate based on whistleblower disclosures, highlighting how systemic faults are often mischaracterised as isolated anomalies—an archetypal case of the “normalisation of deviance.” In parallel, Safety Matters Foundation (India) has raised concerns regarding potential latent failures in aircraft electrical systems and Flight Control Modules (FCMs). To date, the AAIB has not publicly responded to these allegations. The matter is now expected to be addressed before the Supreme Court on 28 January 2026.

A Persistent and Concerning Pattern

Unfortunately, a troubling pattern appears to have emerged within India’s aviation safety ecosystem. Accident reports frequently underplay or obscure root causes, focusing instead on superficial corrective actions that do little to address underlying systemic deficiencies. Preventive measures are often framed in generic terms, while the public remains largely uninformed about structural weaknesses in regulatory oversight, safety assurance, and organisational accountability.

The overarching priority of investigative and regulatory agencies seems less oriented toward transparent safety learning and more toward deflecting responsibility until public attention dissipates. Such an approach not only undermines confidence in the investigative process but also compromises the very purpose of accident investigation: the prevention of future occurrences.

 

Author: GR Mohan