This is a procurement for a commercial, off-the-shelf, flight-critical part where only previously government-approved sources are being solicited. The Government intends to negotiate with a single source, and while it is not a formal competitive request, proposals from other sources may be considered if received within 45 days of the notice's publication. Unapproved sources must submit a comprehensive source approval package with their proposal, as the approval process is lengthy and cannot delay an award. The item is to be delivered FOB Origin.