Mig-21 Unmanned Combat Air System - A Resurrection

Victory smiles upon those who anticipate the change in the character of war, not upon those who wait to adapt themselves after the changes occur. — Giulio Douhet The Command of the Air

 

A Sobering Thought   

A MiG-21 converted to a Kamikaze UCAS can be a very effective bunker buster with high KE penetration (1.4 - 1.8 GJ). Considering 400 kg of jet fuel and a 200 kg HE warhead, it delivers a thermobaric blast inside hardened structures caused by kinetic vaporisation followed by fuel-air catalysis with the warhead acting as secondary charge.   

For comparison, it possesses 60,000 times > KE than propeller driven Shahed-136 Kamikaze drone (7,500 times > jet-powered Shahed-238).  A Shahed-136 carries ≈ 50 kg explosives and ≈ 50 L fuel, generating roughly 2,000 MJ of total chemical energy with virtually zero kinetic penetration. The MiG-21 UCAS unleashes nearly 10 times the total energy of a standard drone strike, with the added capability of delivering that blast inside hardened bunkers due to its high speed kinetic entry.

 

EXECUTIVE SUMMARY

This white paper advocates for the strategic conversion of the Indian Air Force's (IAF) legacy MiG-21 BISON fleet into multi-role UCAS. These retired airframes represent a significant untapped resource for enhancing India’s mass, attrition tolerance, and technological edge in contested environments.

 

STRATEGIC RATIONALE

IAF currently operates around 30 fighter squadrons against a sanctioned strength of 42. Repurposing retired BISONs provides an effective solution to the combat fleet "thinning" in a cost effective manner. Unlike traditional scrapping or display, converting these aircraft into UCAS can bridge legacy manned operations and next-gen unmanned systems.

By breathing new life into these machines, the IAF can transform the perceived weakness of ageing aircraft into a "shield and a spear" for 21st-century conflicts. This strategy aligns with the "Atmanirbhar Bharat" agenda for acquiring autonomous flight controls and AI-enabled kill chain capabilities.

 

UCAS OPERATIONAL ROLES

The proposed BISON UCAS would fulfil three critical roles, maximizing the utilisation of the aircraft’s unique flight characteristics. However, prior to examining them it would be pertinent to briefly examine a typical layered air defence network with overlapping tiers of sensors, command networks, and weapons to detect, track, and neutralize aerial threats at various altitudes and ranges as shown in Figure 1.

Fig.1 – Layered Air Defence Network

1. Kamikaze and Decoy Platforms (SEAD Roles)

The UCAS can be deployed for Kamikaze strike or as attritable decoy.

·       Kamikaze Strike: UCAS could perform an expendable strike mission, carrying HE warhead (up to 500 kg) to destroy hardened infrastructure in high-risk zones.

·       Attritable Decoy: It could simulate RCS and electronic signatures of high-value assets like the Rafale or Su-30MKI, forcing enemy air defences to reveal their positions or exhaust expensive missile inventories on expendable targets.

2. Full Scale, High-Speed Aerial Targets

The UCAS will be uniquely suited for testing Surface-to-Air and Air-to-Air Effectors which require targets that can realistically mimic Mach 2, 17-km service ceiling, and high-G manoeuvres of modern fighter jets. As reusable targets, UCAS will provide far more realistic testing environment and test data than existing low speed targets.

For training missions where no live ordnance is used, the UCAS is flown autonomously, and flying crew practice tracking and locking onto the UCAS using Radar and EO/IR sensors. In such cases, the UCAS lands safely and is reused for future flights. 

In ‘live-fire’ testing and advanced combat exercises, a pilot or AD system actually fires an effector at the UCAS. If the missile makes a direct physical hit or detonates within lethal range, the UCAS is destroyed and crashes into the sea. The retrofitted MDI System provides accurate data on the effector performance as shown in Figure 2. 

Fig.2 – Realistic, Supersonic Target with MDI

 3. Manned-Unmanned Teaming

In an M-UMT framework, the UCAS acts as a "sensor amplifier" for a mothership (e.g., Su-30 MKI or Rafale). Controlled by the manned fighter, the drone could fly ahead for high-threat area surveillance, provide supplementary cover, and engage targets autonomously if required. This collaborative combat role significantly enhances the survivability of the human pilot by allowing the UCAS to absorb enemy fire during deep-strike operations.

Instead of relying on remote ground operators, a ‘loyal wingman’ uses edge-computed AI autonomy to perform dynamic mission profiles based on the manned fighter's real-time needs: -

·       Sensor Forward Scouting: Flying ahead of the crewed fighter to expand the tactical radar and EO/IR image while shielding the human pilot from enemy defences.

·       Weapon Extension: Carrying supplementary effectors that can be targeted and fired via commands from the manned fighter.

·       EW: Active jamming of adversary radars and communication nodes to create safe corridors for the strike package.

·       Tactical Decoys: Flying in high-visibility swarm profiles to confuse enemy AD and absorb incoming missile strikes.

·       Affordable Attritability: Built intentionally at a lower cost-point so they are economically expendable in high-threat, Anti-Access / Area-Denial (A2/AD) zones.

Once policymakers and warfighters absorb the attributes of human-CCA teams, they can address how CCA should operate, manoeuvre, and partner with humans to achieve mission success. Figure 3 illustrates one such concept.

 

Fig.3 – Exploiting CCA for a First-Shot, First-Kill Advantage

A collaborative combat mission scenario with effective communication and survivability for CAP with support of 02 UCASs is shown in Figure 4. 

Fig.4 – CAP with Support of Two UCAS

The friendly fighter's radar detects an enemy aircraft flying towards the airspace. The fighter and UCAV immediately head towards the enemy aircraft. The fighter uses its radar to identify the enemy aircraft. After identifying the enemy aircraft, the fighter, and UCAV divide the tasks. The friendly fighter carries out a frontal attack while the UCAV attacks enemy aircraft from behind.

M-UMT survivability metrics with variable number of UCAVs (‘loyal wingmen’) in a Lethal Envelope Model is shown in Figure 5. 

Fig.5 – M-UMT Survivability Metrics

Note: - Full scope of M-UMT capability discussed in this paper may not be realised in the prototype MiG-21 UCAS or its initial serially produced versions. However, the platform will be a experimental testbed for refining the philosophy and technologies for M-UMT and autonomous combat air vehicles which will control the skies in the near future.  

 

TECHNICAL PROCESS & CONVERSION PATHWAY

The conversion of BISON into UCAS is a complex but manageable engineering task, leveraging mature technologies. The four conversion phases are as follows:-

Phase 0

·       Aircraft Survey: Survey available MiG-21 BISON Airframes and Engines at IAF bases & storage sites 

·       Aircraft Selection: Identify suitable candidate Airframes and Engines for prototype UCAS and serial production 

·       Condition based Life Extension: Limited life extension checks relevant for UCAS role based on sample checks on retired airframes. 

·       Storage Servicing & Preservation:  Develop servicing & preservation schedule of ac in UCAS role based on legacy ac  maintenance schedule 

·       Life Extension of Aircraft:  Perform LE of  prototype UCAS candidates 

·       Servicing of Aircraft:  Storage servicing and preservation of serial production candidates will be performed periodically

The conceptual view of the conversion process is given in Figure 6.

Fig.6 – UCAS Conversion Concept 

Phase 1 – Structural Modification

·       Remove Crew Systems: Non-essential subsystems like Cockpit Controls, Life Support Eqpt, Gun, Ejection Seat & Displays are removed to reduce weight and free internal volume for new avionics.

·       Structural Integrity: Maintain integrity for new autonomous Flight Loads

Phase 2 – Avionics Integration

·       New Systems: Since the BISON lacks modern fly-by-wire systems, an autonomous flight control system and autopilot with terrain matching must be installed to actuate control surfaces and integrated with existing INGPS.

·       Sensor Suite and Avionics Integration: INGPS and Terrain Matching Systems

·       C²: Installation of Mission Computer with real-time telemetry / data links & remote functions.

Core components are shown in Figure 7.

Fig. 7 Core UCAS Components

Phase 3 - Combat Subsystems & Payload Integration

·       Weapon Systems: Installation of HE Warhead with autonomous weapon targeting and fire control systems with modification of existing pylons for payload flexibility.

·       Sensors & EW: Integration of existing Radar, new EO/IR Suite & EW Payloads with MDI & other Sensor Pods. Existing self-protection suite to be retained.

·       Cognitive Ability: Integration of Autonomous Target Recognition & Engagement Capabilities in Control Algorithms 

Note: - While the BISON has a large RCS (making it a good decoy), combat-oriented variants could be coated with Radar Absorbent Material (RAM) to provide limited low-observability during approach.

The conversion process requires significant IAF support in terms of: - 

·       Airbase Infrastructure.

·       MiG-21 BISON Airframes and Engines.

·       Ground and Flight Testing.

·       Airworthiness.

Brief elucidation of the required support is given at Figure 8.

         Fig. 8 – Required IAF Support

Note: - IAF support excludes trained manpower required to perform the conversion. Typically this would be provided through private industry initiative.  

COST BENEFIT ANALYSIS – COMPELLING ECONOMICS

The financial logic of conversion is a powerful argument for UCAS.

·       Conversion Costs: Transforming a BISON into an expendable target drone is estimated to cost between ₹5 to ₹10 crore. A more complex, reusable combat drone conversion is estimated at ₹50 to ₹100 crore.

·       Procurement Comparison: In contrast, procuring a new advanced UCAV like the MQ-9B costs several hundred crores.

·       Maintenance Savings: By utilizing retired airframes as expendable assets, the IAF eliminates the long-term, multi-decade maintenance costs associated with keeping 50-year-old jets airworthy for manned flight.

 

COMPARITIVE GLOBAL PRECEDENTS

·       China: The PLAAF has successfully converted hundreds of J-6 and
J-7 aircraft into a "zombie fleet" designed to saturate enemy air defences in regional conflicts.

·       United States: The USAF uses retired F-16s as QF-16 FSATs and utilizes them in the Skyborg program to test AI-enabled autonomous flight through Project VENOM.

 

CHALLENGES & MITIGATION

Critics of conversion cite the logistics of maintaining an aging fleet and the scarcity of spare parts as major hurdles. Judicious use of existing inventory and newly installed systems can mitigate this concern. As realised by strategists, these airframes are meant to be attritable and expendable and their primary value lies in acting as testbeds for future autonomous technologies and providing mass in "drone-centric" warfare — roles where they are expected to be lost in combat.

 

CONCLUSION

The Indian Air Force stands at a crossroads. Scrapping the MiG-21 BISON fleet would be a loss of high-performance airframes that can still serve the nation as low-cost, supersonic unmanned assets. By converting these aircraft into UCAS for Kamikaze / Decoy, High Speed Aerial Target and M-UMT roles, the IAF can achieve "algorithmic deterrence," enhancing the credibility of its military options while preserving its human capital and high-end fighter fleet.

Actionable Recommendation: The Indian Air Force should seriously consider authorizing a pilot project to convert two BISON aircraft into UCAS for field trials.