RTX Corp., Pratt and Whitney Military Engines, East Hartford, Connecticut, is awarded a not-to-exceed $1,310,000,000 cost-plus-incentive-fee, cost-plus-fixed-fee, undefinitized contract to provide for the design, analysis, rig testing, engine test preparation, developmental hardware, test asset assembly, air system integration, airworthiness evaluation, and product support planning in support of the continued maturation of the F135 Engine Core Upgrade Propulsion System for the F-35 Joint Strike Fighter program for the Air Force, Marine Corps, Navy, and Non-Department of Defense cooperative program partners. Work will be performed in East Hartford, Connecticut (53%) a labor surplus area; Indianapolis, Indiana (15%); Middletown, Connecticut (7%); West Palm Beach, Florida (7%); Windsor Locks, Connecticut (6%); North Berwick, Maine (5%); Rockford, Illinois (4%), a labor surplus area; and Aguadilla, Puerto Rico (3%), a labor surplus area, and is expected to be completed in March 2028. Fiscal 2024 research, development, test, and evaluation (Navy) funds in the amount of $88,392,276; fiscal 2024 research, development, test, and evaluation (Air Force) funds in the amount of $88,392,276; and F-35 cooperative program partners funds in the amount of $39,373,384 will be obligated at the time of award, none of which will expire at the end of the current fiscal year. This contract was not competitively procured pursuant to 10 U.S. Code 3204(c)(1). Naval Air Systems Command, Patuxent River, Maryland, is the contracting activity (N0001924C0042).