Honeywell proposes P40 cooling upgrade for F-35 power system

Honeywell Aerospace has unveiled a proposed upgrade to the power and cooling system fitted to the Lockheed Martin F-35 stealth fighter. The company's "P40" package would raise the aircraft's onboard cooling capacity by 25%, from 32kW to 40kW, according to the manufacturer.

The change would be a modification to the existing Honeywell-made Power and Thermal Management System (PTMS), relying on software updates and what the company describes as targeted liquid-cooling enhancements. Honeywell said the upgrade would not require airframe modifications and could be introduced alongside the ongoing Engine Core Upgrade programme for the F-35's single Pratt & Whitney F135 engine.

Matt Milas, president of Honeywell's defence and space unit, said operators need more cooling capacity and better readiness on a near-term timeline, and that the P40 builds on the PTMS architecture already in service across the global F-35 fleet.

The PTMS is used on all three F-35 variants to cool the fighter's sensors and electronic systems. According to the source, improvements to the aircraft's onboard systems since its original design have pushed it outside its original power and cooling tolerances, requiring more frequent maintenance on the F135 turbofan and raising long-term sustainment costs. That situation prompted the Pentagon to pursue a multibillion dollar engine core upgrade for the F135, which Pratt & Whitney is designing. Rival engine maker GE Aerospace had pushed for a complete replacement of the engine.