Program remains on track to enable Block 4 capabilities in 2029 EAST HARTFORD, Conn., March 23, 2024 /PRNewswire/ -- Pratt & Whitney, an RTX (NYSE: RTX) business, has received full funding in the recently passed fiscal year 2024 Defense Appropriations bill for its F135 Engine Core Upgrade, which will modernize the F-35's propulsion system to increase durability and fully- enable Block 4 capabilities and beyond starting in 2029. "This bill will allow Pratt & Whitney to deliver the current and future propulsi ...