F-35 power- and thermal-management system marks 1 million flight hours
NewsApril 22, 2025
PHOENIX. Honeywell announced that its F-35 Power and Thermal Management System (PTMS) marked one million flight hours since the supersonic F-35 strike fighter aircraft first took flight in late 2006.
The company describes its PTMS as "so integral to key aircraft systems that alterations to its functions would require a high-risk and massively expensive reintegration and retest program to requalify many safety-critical systems." These critical systems include those that cool and pressurize the cockpit, provide oxygen to the pilot, supply emergency power to primary flight controls if the main engine fails, and supply air-cooled avionics to enable a safe landing in case of an in-flight emergency.
Honeywell's announcement about the 1 million flight hours detailed some of the history of the PTMS: Honeywell partnered with Lockheed Martin from the inception of the F-35 Joint Strike Fighter program to jointly develop the PTMS while the aircraft was designed, combining all functions of an auxiliary power unit, emergency power unit, environmental-control system, and thermal-management system into a single integrated package that reduced aircraft weight by 1,000 pounds and aircraft length by nearly a foot from previous-generation systems. Honeywell achieved Technology Readiness Level 6 for the PTMS in 2000 before launching the System Design and Development (SDD) phase, which culminated in its first flight in 2006.
The company also details that it has partnered with Lockheed Martin, the F-35 Joint Program Office, and international allies to establish PTMS repair capabilities in the European and Asia-Pacific regions. In 2022, Honeywell successfully transferred PTMS turbomachine repair capability to Aeronamic, which is co-located at the Royal Netherlands Air Force (RNLAF) base in the Netherlands. Additionally, the company says that a modular test cell is set for delivery to Aeronamic in late 2025 to enable full turbomachine test capability after repairs.
