Honeywell Aerospace announced a proposed upgrade to the Lockheed Martin F-35 Lightning II Power and Thermal Management System on September 22, 2026, aiming to increase the aircraft’s cooling capacity by 25 percent without requiring structural airframe modifications.

The proposed system, designated P40, would increase cooling capacity from 32 kilowatts to 40 kilowatts. According to a company press release, the upgrade is designed to address the thermal management shortfall associated with the F-35 Block 4 modernization program, which introduces advanced sensors, jammers, and the new AN/APG-85 radar. The current cooling deficit forces the existing system to draw additional bleed air from the Pratt & Whitney F135 engine, a process that increases engine operating temperatures and degrades its lifespan.

The P40 Upgrade and Implementation Timeline

Honeywell projects a rollout timeline of three to four years for the P40 upgrade. The company positions the P40 as a lower-cost, interim solution that utilizes software and liquid-cooling hardware upgrades. Because it builds on the existing architecture, the P40 can be installed concurrently with the upcoming Pratt & Whitney F135 Engine Core Upgrade (ECU) during routine maintenance.

Honeywell developed the original F-35 Power and Thermal Management System (PTMS) in the 1990s in collaboration with Lockheed Martin and the F-35 Joint Program Office (JPO). To date, the company has delivered 1,325 PTMS units, which have accumulated over one million flight hours across the global fleet.

“Operators need additional cooling capacity and improved readiness on a timeline that matters. P40 delivers both by building on the proven PTMS architecture already operating across the global F-35 fleet,” stated Matt Milas, President of Defense and Space at Honeywell Aerospace.

The announcement follows Honeywell’s September 15, 2026, disclosure of internal investments aimed at F-35 sustainment, manufacturing capacity, and PTMS reliability improvements. Rich DeGraff, President and CEO of Control Systems at Honeywell Aerospace, noted that sustaining readiness requires ongoing investments in both technology and support capacity to maximize fleet performance.

Competitive Landscape and Block 4 Requirements

The F-35 JPO is currently evaluating options to resolve the thermal management issues. Honeywell’s P40 proposal competes directly with a clean-sheet replacement system pitched by Collins Aerospace, an RTX business.

On August 24, 2026, Collins Aerospace announced that its alternative, the Enhanced Power and Cooling System (EPACS), had completed altitude testing. The EPACS demonstrated a cooling capacity of 80 kilowatts during 2024 laboratory testing. Ira Grimmett, Vice President of Environmental & Airframe Control Systems for Power & Controls at Collins Aerospace, stated that the altitude testing validates system performance in real-world flight conditions and advances the maturity of the EPACS.

The competition centers on balancing immediate cost and integration concerns against long-term capability requirements. While the P40 offers a 40-kilowatt capacity, earlier program discussions indicated that future Block 4 power and cooling requirements could range between 47 and 51 kilowatts, potentially rising further with the integration of the APG-85 radar.

AirPro News analysis

We note that the F-35 Joint Program Office faces a complex procurement decision between an iterative upgrade and a clean-sheet redesign. Honeywell’s P40 proposal offers a pragmatic, lower-risk path that avoids airframe modifications and aligns with the F135 Engine Core Upgrade schedule. However, the 40-kilowatt output falls short of the 47 to 51 kilowatts previously cited for full Block 4 capability. If the P40 is selected as an interim measure, the JPO may still need to fund a more comprehensive thermal management solution later in the aircraft’s lifecycle to fully support the APG-85 radar and subsequent electronic warfare suites. Conversely, selecting the 80-kilowatt Collins Aerospace EPACS would provide significant growth margin but likely at a higher initial integration cost and with a more complex retrofit process for the existing fleet.

Sources: Honeywell Aerospace

The Belgian Air Force received a new batch of three Lockheed Martin F-35A Lightning II fighter jets at Florennes Air Base on September 18, 2026, advancing the nation’s transition to fifth-generation aircraft and keeping its planned transfer of retired F-16s to Ukraine on schedule.

According to reporting by The Aviationist, the transatlantic delivery flight originated at Lockheed Martin Corporation’s facility in Fort Worth, Texas, on September 15, 2026. The aircraft, bearing tail numbers FL-013, FL-015, and FL-016, completed a multi-day journey that included a stopover at Lajes Field in the Azores before arriving in Belgium.

Transatlantic crossing and logistical support

The delivery flight was a joint movement involving six F-35A aircraft, comprising three destined for Belgium and three for the Finnish Air Force. Two United States Air Force (USAF) Boeing KC-135 Stratotankers provided aerial refueling support for the crossing.

While the three Belgian jets successfully completed the final leg from Portugal to Florennes Air Base, The Aviationist reported that one of the accompanying Finnish F-35As remained grounded in the Azores due to an unspecified technical issue.

Fleet modernization and Ukrainian F-16 transfers

Belgium has ordered a total of 34 F-35A fighter jets to replace its aging fleet of General Dynamics F-16 Fighting Falcons. The first batch of three F-35As arrived at Florennes Air Base on October 13, 2025, marking the official start of the type’s operations in the country.

The pace of these fifth-generation deliveries directly impacts European military aid to Ukraine. Militarnyi notes that the arrival of new F-35As dictates the timeline for Belgium to transfer its retired F-16s to the Ukrainian Air Force. Belgium plans to transfer seven F-16s to Ukraine by the end of 2026.

European shared fleet integration

The Belgian Air Force is actively integrating its growing F-35 fleet into broader European defense structures. On September 17, 2026, Belgian aircraft participated in a six-nation mission over Norway under the “Capacity on Call” agreement.

This initiative allows partner nations, including Denmark, the Netherlands, and Norway, to share fleet capabilities. The model supports cross-servicing by allied technicians and the use of shared munitions, optimizing operational readiness across European F-35 operators.

AirPro News analysis

We view the synchronized delivery of Belgian and Finnish F-35As as a demonstration of the growing standardization of European air power. As more NATO nations transition to the Lockheed Martin platform, joint transatlantic ferry flights and shared logistical support will likely become standard practice. The direct link between F-35 deliveries and F-16 transfers highlights how production and deliveries schedules at Lockheed Martin’s Texas facility now have immediate downstream effects on the tactical capabilities of the Ukrainian Air Force.

Sources: Belgian Ministry of Defence

Dassault Aviation has successfully flight-tested two sovereign AI algorithms on the Dassault Rafale fighter jet, advancing the integration of supervised cockpit assistants intended for the upcoming Rafale F5 standard.

In a press release issued on September 22, 2026, from its headquarters in Saint-Cloud, France, the manufacturer announced that the algorithms have reached a maturity level suitable for future aircraft upgrades. One algorithm was developed internally by Dassault Aviation engineers, while the second was co-developed with Thales through its cortAIx artificial intelligence division.

Cockpit automation and pilot workload

The newly tested algorithms are designed to act as controlled and supervised assistants in the cockpit. By handling repetitive tasks, the systems aim to reduce pilot workload during high-intensity operations.

This reduction in manual task management allows human crews to focus on complex combat missions and tactical decision-making. The company stated that the development of these functions is part of a broader initiative to integrate AI into the cockpit, “serving the human crew.”

Integrating these systems into a combat aircraft presents specific engineering hurdles. Dassault Aviation outlined the technical requirements in its announcement:

“This capability requires mastering several key challenges specific to military aviation: ensuring the availability and quality of operational data (real or simulated), leveraging and synergizing domain expertise, and optimizing resource efficiency on an embedded platform subject to stringent constraints.”

The Rafale F5 standard and sovereign defense

The successful flight tests pave the way for the Rafale F5 upgrade, which is targeted for rollout in the 2030s. On September 11, 2026, France awarded contracts to secure the industrial foundation for this new standard.

The Rafale F5 will heavily feature crew assistance, predictive maintenance, and collaborative combat capabilities. These systems will integrate the fighter with unmanned combat aerial systems (UCAS) and other networked assets on the battlefield.

The emphasis on sovereign AI aligns with France’s defense autonomy goals, ensuring critical combat technology remains independent of foreign control. Dassault Aviation has also recently partnered with Harmattan AI to develop embedded AI and electronic-warfare capabilities. This partnership has included collaborative flight-tested demonstrations involving the Dassault Rafale and unmanned aircraft.

AirPro News analysis

We view the emphasis on sovereign AI as a critical differentiator in the European combat aircraft market. By keeping the development of these algorithms strictly within French industrial partners like Thales and Harmattan AI, Dassault Aviation is positioning the Rafale F5 as a fully autonomous platform free from International Traffic in Arms Regulations (ITAR) or other foreign export controls. This independence is a major selling point for export customers seeking advanced collaborative combat capabilities without third-party veto power over their deployment or operational data.

Sources: Dassault Aviation