This acquisition is restricted to sources previously approved by the Government for a flight-critical item, as engineering source approval is required to maintain part quality. Only approved sources have been solicited, and award cannot be delayed to allow new source approval. Any offeror not already approved must submit all required source approval information with their proposal, as outlined in the NAVSUP WSS brochures, or the offer will not be considered. Award will be made only if the offeror, product, or manufacturer meets qualification requirements at the time of award. The acquisition may be subject to trade agreements depending on applicable clauses.