Presolicitation notice from the Department of Defense, Department of the Navy, for the procurement of mainframe and other replacement parts. The parts are used in miscellaneous aircraft accessories and components. The notice specifies the National Stock Number (NSN), technical data package (TDP) version, and quantity of 20 each. Delivery is required FOB origin. The parts require engineering source approval from the design control activity to maintain quality. The approved source(s) retain data rights and manufacturing/repair knowledge that are not economically available to the government. An alternate source must qualify according to the design control activity's procedures. The government does not have sufficient data to purchase the part from sources other than the current one. The item is flight critical and requires government source approval prior to contract award. Interested parties must submit the necessary information for source approval. The notice also provides links to source approval information brochures and commercial item identification brochure. The proposed contract action is for supplies or services for which the government intends to negotiate with only one source. All responsible sources may identify their interest and capability to respond to the requirement. This notice is not a request for competitive proposals. The government will consider all proposals received within 45 days. The government is not using the policies contained in FAR Part 12 for this solicitation, but interested persons may identify their capability to satisfy the requirement with a commercial item within 15 days.