This is a Request for Information (RFI) for market research only and does not constitute a future solicitation. The effort involves engineering and sustainment support for the Terrain Following Radar subsystem of the AN/AAQ-13 Navigation Pod. The contractor will be fully responsible for furnishing all required materials, equipment, and services, including maintenance and calibration at their own or a subcontractor's facility. The current sole source for this work is Raytheon Airborne and Space Systems (RTX), and the Government does not own the necessary data for these items. Participation in this RFI is at no cost to the Government and does not guarantee involvement in any future procurement.