Brazilian Air Force F-39E Gripen completes Operation Thor bomb-release tests

Operation Thor validates F-39E Gripen bomb release

As part of a new stage in the programme to bring Saab F-39E Gripen fighters into service, the Brazilian Air Force’s experimental aircraft, FAB 4100, began trials involving the release of guided and free-fall bombs during Operation Thor at Natal Air Base, Brazil. This latest development confirms the Gripen’s preparedness for air-to-ground attack missions, following the achievement of full operational capability at the end of 2025.

During Operation Thor, the Gripen E underwent demanding assessments intended to confirm that bombs could be released safely, with stable and predictable separation and no risk to the aircraft’s structural integrity. Aviator Colonel Alisson Henrique Vieira, the operation’s general co-ordinator, noted that weapon release is among the most critical stages of flight because “aerodynamic phenomena may occur that generate unsafe situations or damage to the aircraft; therefore everything is meticulously analyzed prior to operational certification.”

The trials used aircraft 4100, assigned to the Gripen Flight Test Centre in Gavião Peixoto, São Paulo. Aviator Major Thiago Camargo of the Institute of Flight Research and Testing (IPEV) flew the aircraft, becoming the first Brazilian pilot to release bombs from an F-39. Every release was observed in real time to assess the fighter’s stability and the precision of separation across varying conditions. Teams at the Maxaranguape firing range prepared the targets and recorded the impacts for later examination.

Mk-84 and Lizard 500 releases

Saab’s Head of Flight Testing, Mikael Olsson, confirmed the successful completion of Operation Thor on 6 February. He underlined that Brazil had become the first operator to release Mk-84 bombs and laser-guided Lizard 500 bombs from the Gripen. He stated that “the data obtained reinforce how the aircraft significantly expands the capabilities of the Brazilian Air Force.” The result is an important step towards further operational testing of the F-39 in ground-attack and tactical-support roles.

Operation Thor joins a series of Gripen programme milestones achieved during 2025. In November, the FAB conducted the first firing of an MBDA Meteor air-to-air missile, completing the integration of the most advanced weapons system in Brazilian combat aviation. The trial demonstrated the F-39E’s capacity to identify and neutralise threats at distances exceeding 150 km, placing Brazil among the limited number of nations operating this long-range weapon. Several weeks later, the fighter carried out its first live-firing exercise with the 27 mm Mauser BK-27 cannon at Santa Cruz Air Base, confirming its accuracy and performance in simulated combat conditions.

Extreme-condition trials and refuelling integration

Earlier in 2025, the experimental Gripen also completed rigorous extreme-condition trials at Anápolis Air Base, where its performance with external stores was assessed at high temperatures and altitude. Fitted with fuel tanks, Diehl IRIS-T missiles and MBDA Meteor missiles, it flew 14 missions in conditions of 32 °C and 1,100 metres above sea level, including eight hot refuelling operations on the ground. The assessments verified the resilience of the flight-control system and the engine’s efficiency under heavy loads, confirming its ability to operate in the demanding climatic conditions found across Brazil.

A further significant advance came in August, when a Gripen was refuelled on the ground for the first time by a KC-390 Millennium under the FARP (Forward Arming and Refuelling Point) procedure. The exercise demonstrated interoperability between the two platforms, cutting turnaround time and extending the fighter’s combat endurance. In November 2025, Saab and Embraer then formally certified the KC-390’s ability to refuel the Gripen in flight. This technical milestone strengthened the integration of both systems and established a new level of operational range for the FAB.

Each earlier test campaign-including missile firings, cannon live-fire exercises, extreme-condition assessments and refuelling certifications-demonstrates the FAB’s commitment to advancing the training and readiness of its Gripen fighters, which will form the future backbone of its combat aviation for decades to come.