Collins Aerospace has completed altitude testing for its Enhanced Power and Cooling System (EPACS), advancing its bid to replace the incumbent thermal management system on the F-35 Lightning II.

In a press release issued on August 24, 2026, the RTX Corporation subsidiary announced that the system ran for several days at power levels replicating mission requirements at its Windsor Locks, Connecticut, facility. The testing validates performance models for delivering emergency power and cooling under flight conditions.

Meeting F-35 cooling demands

The F-35 Joint Program Office (JPO) and prime contractor Lockheed Martin are evaluating options for a new or upgraded Power and Thermal Management System (PTMS). The aircraft requires increased cooling capacity to support the heat generated by Block 4 and subsequent technology upgrades.

The JPO established a cooling capacity objective of 80 kilowatts. Collins Aerospace previously demonstrated that EPACS can achieve this 80-kilowatt threshold in a laboratory setting on January 30, 2024. This output represents more than double the capacity of the current system.

Ira Grimmett, Vice President of Environmental & Airframe Control Systems for Power & Controls at Collins Aerospace, stated that the successful altitude testing validates system performance in real-world Test-Flights conditions.

“Completing this phase of testing advances EPACS maturity and reinforces confidence in the system’s capability and performance,” Grimmett said.

The PTMS competition landscape

Collins Aerospace is competing directly against Honeywell Aerospace, the manufacturer of the incumbent PTMS. Honeywell has proposed upgrading the existing system rather than replacing it entirely to reduce integration risk.

Collins Aerospace announced on February 28, 2025, that EPACS had met requirements for aircraft integration and was cleared internally for full-scale development. The completion of altitude testing marks the next phase in that development pipeline.

Lockheed Martin indicated in March 2025 that the selection process for the F-35 cooling system upgrade could take up to 24 months to finalize.

AirPro News analysis

We view the completion of altitude testing as a necessary technical milestone for Collins Aerospace to prove that a clean-sheet PTMS replacement is viable without introducing unacceptable risk. The F-35 program faces a distinct choice between Honeywell’s upgrade path and the EPACS replacement. With Lockheed Martin’s selection timeline extending into 2027, Collins Aerospace will likely use these test results to argue that EPACS is mature enough to mitigate the integration concerns typically associated with replacing a critical subsystem on an active fighter platform.

Sources: RTX / Collins Aerospace

Shield AI and GE Aerospace have successfully integrated a 1990s-era thrust-vectoring nozzle into the F110-GE-129E engine, clearing a critical Propulsion milestone for the X-BAT autonomous vertical takeoff and landing (eVTOL) strike fighter.

The adaptation of the Axisymmetric Vectoring Exhaust Nozzle (AVEN) enables the 22,000-pound X-BAT to launch and land vertically, eliminating the need for traditional runways. By utilizing flight-proven hardware from previous decades, the companies have significantly accelerated the development timeline for the uncrewed aircraft, which is projected to make its first flight in late 2026.

Resurrecting 1990s Propulsion Technology

Originally developed in the 1990s for the Multi-Axis Thrust Vectoring (MATV) program, the AVEN nozzle was initially tested on a specialized F-16 aircraft at Edwards Air Force Base. During that period, the hardware accumulated 135 flight hours across 95 sorties.

Historical records regarding the nozzle’s initial ground testing vary slightly. GE Aerospace reported 87 hours of ground tests in an August 20, 2026, retrospective article, while a July 20, 2026, joint press release from the companies cited 73 hours.

Shiva Vallabhaneni, Senior Propulsion Engineer for X-BAT at Shield AI, noted the unique nature of the adaptation in a corporate release.

“By combining decades of propulsion engineering with modern autonomy and new aircraft architecture, we’ve transformed a technology built for one mission into the foundation for something its original designers could never have envisioned,” Vallabhaneni stated.

Engine Light-Off and Integration

On July 20, 2026, Shield AI and GE Aerospace announced the completion of integration, actuation, and engine light-off testing at GE Aerospace’s Peebles Test Operation in Ohio. This event marked the first fully integrated test campaign of the AVEN nozzle since its original 1990s development.

The testing validated that the nozzle, the F110-GE-129E engine, actuators, and control systems functioned together as a single propulsion unit.

Armor Harris, Senior Vice President of Aircraft Engineering at Shield AI, emphasized the efficiency of this approach. He explained that taking hardware with a flight-proven track record and adapting it for the X-BAT mission allowed the team to move through development at a rapid pace rather than starting from zero.

U.S. Navy Rimes Program Contract

The propulsion milestones align with growing military interest in runway-independent platforms. On August 14, 2026, Aviation Week reported that the U.S. Navy awarded Shield AI a $50 million Contracts to develop the X-BAT under the Runway Independent Maritime Expeditionary Strike (Rimes) program.

According to the publication, the Navy intends to operate the VTOL aircraft from destroyers, expeditionary sea bases, and aircraft carriers to execute long-range strike missions.

AirPro News analysis

We view the integration of the AVEN nozzle as a highly pragmatic engineering decision by Shield AI. Developing a clean-sheet VTOL propulsion system for a 22,000-pound strike fighter would typically require billions of dollars and over a decade of testing. By mating an existing, flight-proven thrust-vectoring nozzle to the widely used F110 engine family, the company bypasses the highest-risk phases of aerospace propulsion development.

Furthermore, the X-BAT concept directly addresses a primary concern for modern military planners: the vulnerability of fixed airbases and large aircraft carriers. Distributing autonomous strike capabilities across smaller surface vessels like destroyers and expeditionary sea bases requires robust VTOL performance, which the AVEN technology now appears ready to provide.

Sources: GE Aerospace

Saab AB unveiled a full-scale concept model of a supersonic, low-observable uncrewed combat air system, designated the A3-001, during the Jubilee Air Show at Malmen Air Base in Linköping, Sweden, on August 22, 2026.

The presentation, which coincided with the 100th anniversary of the Swedish Air Force, outlines the manufacturers vision for a high-end autonomous platform designed to operate alongside crewed fighters like the Saab Gripen E. According to a company press release, the A3-001 is intended for high-risk missions in heavily defended airspace, including electronic warfare, suppression of enemy air defenses (SEAD), and precision strikes.

Pathway to the A3-001 concept

While the A3-001 represents a future operational vision targeted for the mid-2030s, Saab is currently developing two uncrewed technology demonstrators, designated A1 and A2, under its Autonomous Collaborative Platform (ACP) roadmap. These initial demonstrators are funded by the Swedish Ministry of Defence.

Reporting by The War Zone indicates that the A1 demonstrator is expected to make its first flight within approximately 15 months. The A1 will be powered by a General Electric (GE) F414 engine, which is the same powerplant utilized in the Gripen E and F models.

“We are currently in an intensive development phase where, together with Sweden, we are exploring technologies that will lay the foundation for the next generation of combat air systems,” said Peter Nilsson, Head of Business Unit Advanced Programs at Saab AB. “As part of this work, we intend to fly uncrewed demonstrators with fighter-like characteristics before 2030 as we support Sweden in considering their future options.”

Strategic positioning and future combat systems

The A3-001 concept falls under Sweden’s broader Koncept för Framtida Stridsflygplan (KFS), or Concept for Future Combat Aircraft project. The War Zone notes that the A3-001 is positioned as a higher-end, larger, and faster platform compared to the Collaborative Combat Aircraft (CCA) currently under development for the United States Air Forces.

Saab intends for the A3-001 to leverage the company’s existing sensor and command infrastructure. Nilsson stated that the A3 system is a concept for what could follow the demonstrator phase should the Swedish government decide to proceed with development.

“Saab is well positioned to develop the next generation of combat air systems building on Gripen and GlobalEye, combined with our long experience in advanced aerospace systems,” Nilsson said.

AirPro News analysis

We view Saab’s decision to power the near-term A1 demonstrator with the GE F414 engine as a pragmatic approach to reducing developmental risk. By utilizing the same propulsion system as the Gripen E, Saab ensures immediate logistical and maintenance commonality, which is critical for testing manned-unmanned teaming concepts. It is necessary to distinguish between the funded A1 and A2 demonstrators and the A3-001 mock-up showcased on August 22, 2026. The A3-001 remains a company-funded concept illustrating potential future capabilities rather than an active acquisition program. Its realization will depend entirely on future procurement decisions by the Swedish Armed Forces following the data gathered from the A1 and A2 flight test campaigns.

Sources: Saab AB