Spain has selected the Airbus A321 as the platform for a new signals intelligence aircraft, according to a publication from the Spanish Air and Space Force, ending uncertainty over the aircraft that will form the basis of the Santiago II-SCAPA program.
The selection appeared in the October edition of Revista de Aeronáutica y Astronáutica, the service's official publication. Spain's Ministry of Defense has not separately announced the decision, but previous government documents said the first phase of Santiago II would define the aircraft platform before three SIGINT aircraft are acquired.
The program is intended to give Spain a dedicated airborne SIGINT capability again more than a decade after the retirement of its specially equipped Boeing 707. The TM.17-4, known as Reina del Espectro, performed electronic and communications intelligence missions before its final operational flight in 2014.
Airbus and Indra are already working on Santiago II under a definition contract awarded in December 2025. The approximately €16 million (US$19 million) agreement covers an 18-month study, with Airbus responsible for work on the aircraft platform and Indra focused on sensors and mission systems.
Three A321s planned for SIGINT role
Spanish government documentation calls for three aircraft equipped to detect, locate, identify and analyze electromagnetic emissions. The program also requires manufacturing and systems integration in Spain, including national control over the integration of the SIGINT equipment.
The use of the A321 gives the program a considerably larger platform than business jets commonly adapted for intelligence missions. Its cabin provides space for mission operators and equipment, and the aircraft has the endurance and payload capacity required for long intelligence-gathering missions.
Follow Air Data News: WhatsApp | Instagram | LinkedIn | Twitter | Facebook
Spain previously operated other dedicated electronic warfare aircraft in addition to the Boeing 707, including Dassault Falcon 20s. Their retirement left the country without the specialized airborne capability that Santiago II is intended to restore.
The A321 could eventually serve another Spanish surveillance requirement. The Air and Space Force publication discusses the possibility of using the same platform for a future airborne early warning aircraft, although Spain has not launched an A321-based AEW acquisition program.
Airbus is already developing another military special-mission version of the A321 for France. The A321 MPA was selected to replace the French Navy's Atlantique 2 maritime patrol aircraft, although its mission and equipment will differ substantially from Spain's SIGINT configuration.
The next phase of Santiago II is expected to cover development and integration of the intelligence systems into the three aircraft after completion of the current definition work.
