Raytheon Technologies‘ [RTX] Collins Aerospace said last week at the Paris Air Show that it has conducted a lab test in Windsor Locks, Conn., of the Enhanced Power and Cooling System (EPACS) that Collins Aerospace plans to offer as a Power and Thermal Management System (PTMS) replacement for the Honeywell [HON] PTMS now carried on the Raytheon Pratt and Whitney F135 engine that powers the

Lockheed Martin [LMT] F-35 fighter.

EPACS, which includes a Collins Aerospace air cycle system, electric power generator and controller and a Pratt & Whitney auxiliary power unit, is to achieve Technology Readiness Level 6 this year and could enter “an Engineering and Manufacturing Development program as early as 2024,” Collins Aerospace said.

The PTMS uses air pressure from the engine to cool aircraft subsystems and enables main engine start, emergency power, cockpit conditioning, equipment cooling, and some electrical power.

Last month, a Government Accountability Office (GAO) report said that the F135 will need a new or improved PTMS to accommodate future weapons and sensors on the aircraft (Defense Daily, May 30). The question appears to be when.

The U.S. Air Force decided this year to cancel the Advanced Engine Transition Program to develop and field a new, adaptive cycle engine on the F-35 and instead to move ahead with the Pratt & Whitney F135 Engine Core Upgrade (ECU).

The GAO report said that the F135’s cooling system “is overtasked, requiring the engine to operate beyond its design parameters” and that “the extra heat is increasing the wear on the engine, reducing its life, and adding $38 billion in maintenance costs.”

While the F-35 Joint Program Office (JPO) has said that it is “very confident we can minimize the $38 billion impact simply with ECU,” the GAO report called into question whether the F135 ECU will provide enough cooling to accommodate new Block 4 weapons and sensors on the F-35 or whether the F135 ECU will need a new or upgraded PTMS as well to allow Block 4.

“Through its more efficient thermodynamic cycle, EPACS provides significantly more cooling capacity to the platform and requires less energy from the engine, thus helping to unlock improved engine performance and durability,” Collins Aerospace said last week at the Paris Air Show. “The system will deliver more than twice the current cooling capability to support additional growth beyond Block 4 and is expected to provide enough cooling capacity for the life of the aircraft. In addition, EPACS fits within the existing envelope and is intended to be compatible with all three F-35 variants.”

Ira Grimmett, the vice president of Collins Aerospace’s environmental and airframe control systems, said that EPACS “is a mature system that will help maximize F-35 performance for decades to come.”

Jill Albertelli, president of Pratt & Whitney’s military engine business, said last week that “the F135 ECU paired with an upgraded PTMS can provide 80KW [kilowatts] or more of cooling power for the F-35, which will exceed all power and cooling needs for the F-35 through the life of the program.”

Pratt & Whitney is gearing up to finish the preliminary design review (PDR) of the F135 ECU and is planning to enter the detailed design phase for the F135 ECU early next year (Defense Daily, June 22). P&W said that it has more than doubled the number of F135 ECU workers from 200 to 500 to satisfy that goal.