The Department of Defense, specifically the Department of the Navy through NAVSUP Weapon Systems Support, is seeking proposals for the repair and modification of a combustion chamber liner, identified by NSN 7R-2840-016784153-TN, with a quantity of 13 units required. This procurement necessitates engineering source approval due to the flight-critical nature of the item, which mandates that only approved sources may be considered for the contract, as they possess the unique design capabilities and technical data essential for maintaining quality. Interested parties must submit their proposals along with the necessary source approval documentation within 45 days of this presolicitation notice, and any proposals lacking the required information will not be considered. For further inquiries, potential bidders can contact Charles F. Horan at (215) 697-1303 or via email at CHARLES.F.HORAN@NAVY.MIL.