French Navy’s First FDI Frigate Completes 123-Day Global Combat Trial Before Active Service.

The French Navy’s first Defence and Intervention Frigate, Amiral Ronarc’h, has completed the main evaluation phase of its long-duration deployment, Naval Group reported on July 21, 2026. The 123-day mission tested whether the 4,500-tonne warship can sustain combat operations across widely different climates while maintaining crew effectiveness and system reliability.

After sailing 24,850 nautical miles from the Arctic to the Gulf of Mexico and the Mediterranean, the frigate generated operational data on its combat system, propulsion, cooling, maintenance demands, and workload. A scheduled maintenance period in Brest from September to December 2026 will prepare the ship for the final steps toward active service and strengthen France’s capacity for long-range naval deployment.

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French Navy frigate Amiral Ronarc’h undergoes extended operational trials to validate its Sea Fire radar, Aster air-defence missiles, Exocet anti-ship armament and anti-submarine warfare systems before entering active service (Picture source: Naval Group).

The frigate is the first of five French FDI ships ordered through a programme launched in 2017. Amiral Ronarc’h was floated in November 2022, began sea trials on October 7, 2024, and was delivered almost one year later than the schedule announced when construction started. The remaining ships, Amiral Louzeau, Amiral Castex, Amiral Nomy and Amiral Cabanier, are planned for delivery between 2027 and 2032. Their arrival will allow France to withdraw the five La Fayette-class frigates while retaining a force of 15 first-rank frigates: two Horizon air-defence frigates, eight FREMM frigates and five FDI frigates. That number is a force-planning requirement rather than a reserve; individual ships must cover carrier escort, ballistic-missile submarine protection, NATO assignments, national deployments and maintenance periods.

Amiral Ronarc’h measures 122 metres in length and 18 metres in beam, has a maximum speed of 27 knots and is designed for deployments of up to 45 days. Naval Group lists accommodation for 125 crew members and 28 additional personnel, while the French Navy reported an operating complement of 132 sailors in July 2026. The machinery arrangement includes four diesel engines and six main generators plus one reserve generator. This conventional propulsion choice limits acquisition and support complexity, but it also makes the extended trial important: operating computer rooms, sensors, weapons and hotel services at air temperatures of 36-37 degrees Celsius places sustained demand on electrical generation and chilled-water systems.

The frigate’s air-defence system combines the Naval Group SETIS combat management system, a Thales Sea Fire radar and Sylver A50 vertical launchers for MBDA Aster missiles. Sea Fire uses four fixed active electronically scanned array faces rather than a mechanically rotating antenna. It can conduct air and surface surveillance while supporting missile engagements, scans to 90 degrees in elevation and, according to Thales qualification data, covers several hundred kilometres. The fixed-array arrangement provides continuous sector coverage and short update intervals, which are relevant when tracking low-altitude anti-ship missiles or several threats approaching on different bearings. Aster 15 has an approximate engagement range of 30 kilometres and is primarily intended for self-defence and local escort protection; Aster 30 extends the defended area to approximately 100 kilometres. Both use active radio-frequency terminal guidance and combined aerodynamic and lateral-thrust control, with Aster 30 reaching up to Mach 4.5.

The current French configuration has 16 Sylver cells, compared with 32 cells on the Greek FDI frigates. This is a material limitation rather than a minor configuration difference. A 16-cell magazine must cover aircraft, cruise missiles, unmanned aerial vehicles and potentially anti-ship ballistic threats, while some engagements may require more than one interceptor. French Senate hearings in November 2025 confirmed that ships four and five were being considered for 32 cells, and subsequent parliamentary documents called for the first three frigates to receive the same capacity. Doubling the launcher count would improve endurance during repeated attacks, but it would not by itself solve the broader issue of missile availability; France ordered 180 additional Aster missiles for the 2025–2035 period and has been increasing production after operational expenditure in the Red Sea.

Anti-surface armament consists of eight Exocet MM40 Block 3C missiles in two four-round launch groups. The missile weighs 530 kilograms, is 4.7 metres long and uses programmable three-dimensional waypoints, allowing the flight path to avoid defended sectors or approach a target from a selected bearing. MBDA also specifies simultaneous terminal attacks, operation in dense electronic-warfare conditions and a land-attack function. The Block 3C therefore gives the frigate an over-the-horizon strike option against warships and selected coastal targets, although target-quality data at extended range must come from the ship’s helicopter, another aircraft, an unmanned aerial vehicle or an external surveillance network. A Leonardo 76/62 Super Rapid gun provides a lower-cost weapon against surface craft and some air targets. Its selectable firing rate reaches 120 rounds per minute, with 80 ready rounds in the mounting, while a Thales STIR radar supplies gun-fire control. Two remotely operated Narwhal 20 mm guns cover close-range threats such as small boats.

For anti-submarine warfare, Amiral Ronarc’h carries a CAPTAS-4 Compact variable-depth sonar, a bow sonar, four reloadable torpedo tubes and MU90 lightweight torpedoes. CAPTAS-4 Compact can lower its active source and receiving array below temperature layers that reduce the effectiveness of a hull-mounted sonar, giving the frigate a better probability of detecting a submarine operating in deep or acoustically complex water. The MU90 provides the terminal attack weapon, while CANTO-V acoustic countermeasures are intended to confuse an incoming torpedo by producing multiple false contacts rather than merely seducing it toward one decoy. The hangar can support an NH90 Caïman Marine helicopter, whose dipping sonar, sonobuoys and torpedoes extend the search and attack area well beyond the ship. The frigate can also operate a rotary-wing unmanned aerial vehicle of up to 700 kilograms.

France requires the FDI because the La Fayette class cannot provide comparable area air defence or long-range submarine detection, and because the eight FREMM and two Horizon frigates are insufficient to cover every first-rank task without a third frigate class. The FDI provides more combat capability than its displacement suggests, but its value will depend on practical factors now being measured: radar availability, software stability, acoustic performance, cooling margins, missile inventory, helicopter integration and maintenance burden with a relatively small crew. The 2026 deployment was therefore not proof that development had ended; it was a controlled effort to identify deficiencies before four additional French frigates inherit the same design.

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