Here's a little info on SAFE FLIGHT 21 via this link:
http://www.mitrecaasd.org/work/proje...fm?item_id=150
So, it's possible that the thousands of SAFE FLIGHT 21 registrations have been participants / test subjects to the SAFE FLIGHT 21 project. I was out at Kitty Hawk for the Centennial of Flight Celebration in 2003 and I remember SAFE FLIGHT (Capstone) was a big deal back then.
Mike
First paragraph from the website:
Safe Flight 21 is a cooperative effort between government and industry to develop enhanced capabilities for Free Flight based on evolving Communications, Navigation, and Surveillance (CNS) technologies. Safe Flight 21 will demonstrate an in-cockpit display of traffic, weather, and terrain information for pilots. The technology will also provide improved information for controllers. This program uses Global Positioning System (GPS), Automated Dependent Surveillance-Broadcast (ADS-B), Flight Information Services-Broadcast (FIS-B), Traffic Information Service-Broadcast (TIS-B), and their integration with enhanced pilot and controller information displays. Safe Flight 21 will evaluate the safety, service, and procedure improvements these technologies make possible. The first evaluations were performed in the Ohio Valley in July 1999 and in Alaska one month later in what is called Alaska/Capstone.