Spain, Germany and Belgium moved ahead on 8 October 2026 with the second phase of a European Defence Agency (EDA) Research, Technology and Innovation project towards the automation of mid-air hose-and-drogue refuelling of military aircraft. The final aim of the project is to enable air-to-air refuelling between unmanned aircraft.
The new phase, estimated at €8 million, builds on the project EDA launched with Spain and Germany in 2022.
Phase One, which used an Airbus A330 MRTT tanker, a German Tornado jet and a Spanish F-18 for flight tests, proved the automation was technically feasible. It developed camera-based tracking of the drogue and receiver aircraft and tested ways to stabilise the drogue in flight.
Phase Two, led by Spain with the support of Germany, and with Belgium now joining, focuses on refuelling unmanned aerial vehicles (UAVs). Where the first phase sought to prove automation could work with piloted jets, the new phase aims to bridge the technical gaps in the automation of air-to-air refuelling operations required to coordinate multiple unmanned receivers with a single tanker at once.
The project lays the groundwork for future automated air-to-air refuelling capabilities, essential to the interoperability of European and NATO air forces.
Phase Two will explore technologies for relative navigation, which lets an aircraft determine its position and motion with respect to another aircraft rather than to a fixed global reference like GPS. It will also cover image sensors, connectivity between assets, and the hardware needed to process sensor data and run tracking algorithms. The project should enable future autonomous air-to-air refuelling (A4R) operations with European technology.
Work will unfold in three stages:
- simulated multi-aircraft refuelling operations involving several receivers at once;
- laboratory testing using robotic arms to mimic the motion between hose and receiver;
- ground and flight tests to gather additional data from tanker and receiver aircraft.
Spain’s priority and partners
Spain sees itself as a global leader in air-to-air refuelling, and its Defence Technology and Innovation Strategy (ETID 2026) identifies the area as a priority. By advancing the technology readiness level of the hose-and-drogue system, Spain aims to consolidate that position.
EDA’s role
As the contracting authority, EDA's role is to support the three Member States, including in coordinating the multinational effort, agreeing on technical requirements and managing risks.