The requirement is for 4 each of a flight-critical part (NSN 0R-7010-017078551-P8), delivery FOB origin, with acquisition limited to Government-approved sources. The item requires engineering source approval by the design control activity because approved sources retain essential design, manufacturing, and repair data not economically available to the Government. The Government intends to solicit and negotiate with only one source under FAR 6.302-1, and only previously approved sources have been solicited; award cannot normally be delayed pending approval of a new source. Responsible non-approved sources may identify interest and capability and must submit the source approval information required by the applicable NAVSUP WSS brochure with their proposal. The Government states FAR Part 12 commercial-item policies are not being used, though interested parties may identify commercial-item capability to the contracting officer.