Collins Aerospace completes altitude tests for F-35 cooling system

Collins Aerospace has completed altitude testing for its Enhanced Power and Cooling System (EPACS), designed to significantly increase the thermal capacity of the Lockheed Martin F-35 Lightning II. The testing involved several days of operation at power levels replicating mission requirements and across various simulated altitudes to validate performance under real-world flight conditions.

EPACS is intended to provide up to 80kW of cooling, which is more than double the capacity of the current Honeywell power and thermal management system. This increased capacity is necessary to support future technology upgrades, such as new sensors, computing hardware, and mission systems that generate significant heat and electrical power demands.

Collins Aerospace stated that the existing system is currently overtasked, forcing the F135 engine to operate beyond its design parameters and increasing lifecycle costs. The EPACS technology reached technology readiness level 6 in February 2025 and is designed to fit within the aircraft’s existing installation to minimize integration and operational risks across all three F-35 variants.