The French Air Force is retiring its KC-135RG aircraft in favor of the A330 MRTT, strengthening its refueling and strategic transport capabilities.

On July 7, 2025, the French Air and Space Force officially retired its last KC-135RG refueling aircraft, marking the end of a cycle of more than 60 years of operational service. Transferred from the United States in the 1990s, these aircraft have played an essential role in in-flight refueling missions for the French Air Force, both in mainland France and overseas. They are now being replaced by a fleet composed entirely of more modern and versatile Airbus A330 MRTT Phénix aircraft.

The retirement of the KC-135RG aircraft comes with the delivery of a thirteenth A330 MRTT, consolidating a transition that began in 2018. This technological upgrade significantly improves France’s operational performance in terms of refueling, cargo transport, and strategic projection. It also reflects a desire to streamline resources, with the implementation of a single multi-role system replacing several platforms.

The end of service for the KC-135RG also raises questions about France’s logistical independence from the United States, as the older aircraft have required US structural support for decades. This withdrawal highlights a shift in doctrine, focusing on aircraft versatility and alignment with European standards. It is less a gradual modernization than a deliberate change in the logistics model.

A refueling aircraft inherited from the Cold War

The American origin of the French KC-135RG

The KC-135RG aircraft integrated into the French Air Force between 1997 and 2000 came from the former US KC-135E fleet. These rigid-boom refueling aircraft were modified at the time to incorporate CFM56 engines—a Franco-American design—offering greater thrust and reduced fuel consumption. The designation “RG” corresponds to the modernized variant upgraded to French aviation safety standards.

With a refueling capacity of 91,000 liters of fuel, the KC-135RG could supply Mirage 2000, Rafale, and allied aircraft equipped with compatible probes. It had a range of over 6,500 kilometers with a full tank and a cruising speed of around 850 km/h. The aircraft carried a dedicated refueling operator, positioned at the rear, with a direct view of the refueling station.

A total of 11 aircraft were operated by France from the 125th Air Base in Istres. They played a central role in Operation Chammal, the Barkhane mission in the Sahel, and NATO exercises. Their average availability was 60%, a rate considered acceptable but which has deteriorated since 2020 due to the aging of the airframes and the reduction in available spare parts.

Increasing logistical constraints

With an average age of over 60 years, the KC-135RG aircraft required extensive inspections, costly upgrades, and technical expertise that has become scarce. Maintaining them in operational condition required the use of US subcontractors, particularly for specific structural components such as stringers, boom mounts, and original Boeing hydraulic sensors.

Maintenance costs per flight hour amounted to more than $25,000, not including frequent interruptions due to fuel system wear or metal cracks. In comparison, the operating cost of an A330 MRTT is estimated at $12,000 per flight hour, while offering significantly greater fuel capacity: 111,000 liters.

The MRTT Phénix gains momentum in a streamlined format

The choice of a single, modular platform

The MRTT Phénix program was launched to replace not only the KC-135RG, but also the Airbus A310 and A340 strategic transport aircraft previously used for cargo and medical evacuation. This capability sharing approach is based on a multi-role aircraft derived from the A330-200, configured for in-flight refueling, passenger, cargo and medical evacuation.

The MRTT uses a rigid refueling system operated from a digital control station with panoramic vision. It can refuel two fighter jets simultaneously via underwing pods, or a large aircraft via the boom. The integration of French military IT architecture (SIC-S) enables centralized monitoring of operations and inter-service coordination.

France has ordered 15 aircraft in total, of which 13 have been delivered to date. Each aircraft costs around €210 million, including military equipment and the necessary ground infrastructure. The MRTTs are stationed at Istres, but can also be deployed to planned bases such as Niamey, Djibouti, and the United Arab Emirates.

Enhanced performance and extended range

Compared to the KC-135RG, the A330 MRTT offers 22% more fuel, a cabin that can be configured as needed, a transport capacity of 272 passengers or 45 tons of cargo, and a range of 14,800 kilometers without refueling. It is also compatible with new aircraft in service, including European MALE drones, which require specific liaison standards.

The MRTT also features modernized civil avionics that comply with European air safety standards, facilitating its integration into civil air corridors. It can fly in radar-silent mode, operate in complete darkness and integrate 16-hour mission cycles with two crews. This flexibility enables airborne nuclear deterrence missions with the Rafale ASMPA.

The MRTT is now a cornerstone of French deterrence and strategic projection, strengthening its ability to conduct long-range raids or maintain a presence in the Indo-Pacific region. The modernization of the aircraft format is therefore closely linked to France’s military posture outside its national territory.

A symbolic and doctrinal break for the French Air Force

End of a transatlantic legacy

The abandonment of the KC-135RG marks the end of a major logistical link between Paris and Washington. Even when modernized, these aircraft remained tied to US standards for maintenance, refueling, and doctrine. Their replacement by a system designed and assembled in Europe represents a strategic refocusing on sovereign capabilities, in line with France’s desire for strategic autonomy.

This transition is also reflected in training. MRTT pilots and operators are now trained on a European simulator in Blagnac, rather than on an American platform. Maintenance cycles are carried out by Airbus Defence and Space, with a logistics network based in France and Spain. The withdrawal of the KC-135RG also frees up specialized hangars, which will be refurbished for the MRTT fleet and the future Eurodrone MALE drone.

An operational gain but a loss of endurance

Despite the MRTT’s many advantages, some former pilots regret the mechanical robustness of the KC-135, which was able to take off again after a failure thanks to its technical simplicity. Although more reliable on paper, the MRTT requires more complex maintenance logistics due to its advanced avionics and integrated components.

In addition, the unavailability of a single MRTT can have a significant impact on deployment plans, given the small number of aircraft. One unavailable aircraft represents nearly 7% of France’s total strategic refueling capacity. The optimized format therefore relies on impeccable technical availability, with reduced margins of error.

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