F-35 Cooling Crisis: Collins and Honeywell Engage in High-Stakes Battle

The F-35 Lightning II, America's most advanced fighter jet, has a major problem: it runs too hot. The increasing number of sensors, jammers, and processors added to the jet have generated more heat than its original design can handle, putting a strain on its thermal management system.

Collins Aerospace, an RTX business, has completed altitude testing of its Enhanced Power and Cooling System (EPACS), which is designed to replace the current Honeywell system. EPACS demonstrated 80 kW in lab testing in 2024, more than double what the current system provides. Collins claims that EPACS can handle real-world flight conditions.

Honeywell, the incumbent supplier, is fighting to keep its contract by offering a phased upgrade of the existing system. This would involve a software change that would lift capacity to around 40 kW within two to three years, avoiding the cost and risk of replacing the entire system.