Honeywell Aerospace has launched an upgrade designed to give F-35 fighters more cooling capacity as new sensors, mission systems, and computing hardware increase demand for thermal management.
Called P40, the upgrade raises the F-35’s Power and Thermal Management System (PTMS) capacity from about 32 kilowatts to 40 kilowatts, a 25 percent increase. It combines software updates with targeted changes to the aircraft’s liquid-cooling system.
The company expects the upgrade to enter service between 2029 and 2030.
“Operators need additional cooling capacity and improved readiness on a timeline that matters,” Matt Milas, president of Defense and Space at Honeywell Aerospace, said.
Rather than replacing the existing system, P40 expands its capacity within the current architecture.
Honeywell said this approach would allow operators to retain existing repair facilities, tooling, and technical expertise while avoiding the extensive redesign and qualification work required for a new thermal-management system.
What P40 Brings
Cooling has become a bigger concern as the F-35 receives additional computing and mission capabilities. Technology Refresh 3, for example, adds processing power and memory needed for future capabilities, while the broader Block 4 modernization effort is adding new systems to the aircraft.
The Government Accountability Office has also reported that the F-35’s current cooling system has been overtasked, requiring the engine to operate beyond its original design parameters. The resulting additional heat has increased engine wear and reduced its expected service life.
The PTMS has accumulated more than 1 million flight hours across the global F-35 fleet. The system supports 14 mission- and safety-critical functions, including auxiliary and emergency power, engine starting, environmental control, and thermal management.
