Because demand for ADS-B upgrades to Pro Line 4 and 21 platform aircraft has been great, Rockwell Collins is experiencing long lead times for upgraded and new GPS-4000S GPS/WAAS (Wide Area Augmentation System) receivers.
Anticipating that this might occur, Duncan Aviation sent many unmodified units to Rockwell Collins for upgrades, and we now have an exchange pool available for these units. Each unit is certified and modified, and there will not be any delay during your ADS-B upgrade. Rockwell Collins expects to have a solution soon for this shortage.
Collins Aerospace TDR-94D Transponders
Performance Based Navigation