This is a sole-source solicitation for 20 flight-critical parts, requiring government source approval prior to contract award. Only previously approved sources have been solicited, and the approval process for a new source is typically too lengthy to delay an award. Unapproved sources must submit a detailed source approval request with their proposal, using specified NAVSUP WSS brochures. The Government intends to negotiate with only one source, but it will consider proposals received within 45 days of the synopsis publication for the purpose of determining whether to conduct a future competitive procurement.