Honeywell Power And Thermal Management System Marks One Million Flight Hours Aboard F-35

PHOENIX, March 11, 2025 – Honeywell (NASDAQ: HON) today announced that its F-35 Power and Thermal Management System (PTMS) has achieved one million flight hours since the F-35 first took flight in late 2006. Honeywell’s PTMS is the only system of its kind on any aircraft, and its performance and maturity have been proven on over 1,100 F-35 aircraft delivered to the U.S. and allied nations.

Honeywell partnered with Lockheed Martin from the inception of the F-35 Joint Strike Fighter program to jointly develop the PTMS in concert with the aircraft, combining all functions of an auxiliary power unit, emergency power unit, environmental control system and thermal management system into one integrated package that reduced aircraft weight by 1,000 pounds and length by 10 inches 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.

“Our PTMS achieving one million flight hours reinforces why Honeywell is best positioned to deploy extensive experience, resources and technical capabilities to meet current and future F-35 cooling capacity needs for American and allied warfighters,” said Matt Milas, President, Defense and Space, Honeywell Aerospace Technologies. “Honeywell’s PTMS is interwoven into the key systems of the F-35, and the schematics clearly show that it is the heart and circulatory system of the F-35. In addition to supplying cooling ­­– which is its most basic function – the PTMS performs 13 other mission- and safety-critical aircraft functions that require extensive integration and software qualification.”

The proven Honeywell PTMS is 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 include systems 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 during an in-flight emergency.

“Honeywell’s solution for increasing the PTMS cooling capacity minimizes risk and cost,” said Rich DeGraff, President, Control Systems, Honeywell Aerospace. “This approach preserves the F-35's critical functions and has been proven not only through in-service flight hours, but thousands of additional hours in our dedicated F-35 test cell – the world’s most representative test cell of the F35 thermal ecosystem. Our engineering experience and investment in air and thermal management systems for both military and commercial aircraft is unmatched.”

Honeywell’s PTMS is supported by a world-class service network around the globe. Honeywell 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 Woensdrecht, Netherlands. A modular test cell is on track for delivery to Aeronamic in late 2025 to enable full turbomachine test capability after repairs.

The U.S. military has also worked with Honeywell to establish a PTMS depot and test capabilities at Fleet Readiness Center East in Cherry Point, North Carolina. Additionally, Honeywell is pursuing opportunities in Australia to transfer repair capabilities for a select group of PTMS components to ensure global support for this critical system wherever F-35s are fielded.

About Honeywell

Products and services from Honeywell Aerospace Technologies are found on virtually every commercial, defense and space aircraft, and in many terrestrial systems. The Aerospace Technologies business unit builds aircraft engines, cockpit and cabin electronics, wireless connectivity systems, mechanical components, power systems, and more. Its hardware and software solutions create more fuel-efficient aircraft, more direct and on-time flights and safer skies and airports. For more information, visit aerospace.honeywell.com or follow Honeywell Aerospace Technologies on LinkedIn.

Honeywell is an integrated operating company serving a broad range of industries and geographies around the world. Our business is aligned with three powerful megatrends – automation, the future of aviation and energy transition – underpinned by our Honeywell Accelerator operating system and Honeywell Forge IoT platform. As a trusted partner, we help organizations solve the world's toughest, most complex challenges, providing actionable solutions and innovations through our Aerospace Technologies, Industrial Automation, Building Automation and Energy and Sustainability Solutions business segments that help make the world smarter and safer as well as more secure and sustainable. For more news and information on Honeywell, please visit www.honeywell.com/newsroom.