Here are answers to frequently asked questions.
Where does the snapshot image come from?
The images are provided by Flight Explorer, the leading provider of real-time, Internet based flight tracking and information systems. They were specifically designed for FlightWeb and are refreshed every 5 minutes.
How is the image data generated?
The information comes from flight plans and radar track data from the FAA Air Route Traffic Control Centers. This information is combined into one data stream and fed to Flight Explorer. Until recently, this information was available only to airlines and large corporate flight centers.
What determines which aircraft are displayed?
The Lifeguard Snapshot includes only those aircraft that have filed an IFR flight plan and have requested Lifeguard status. This generally means fixed-wing air ambulances and IFR EMS helicopters. A VFR fixed-wing or helicopter may appear while transitting through Class 'B' airspace if they have declared as Lifeguard or if they are crossing multiple ATC control areas and are being flight-followed by ATC.
Lifeguard is a special radio callsign used by air ambulances to receive special handling by Air Traffic Controllers. Some programs use Lifeguard on virtually all flights, while others only use it rarely. This is why some services may appear on the snapshot more than others, regardless of the actual number of flights being done. Any aircraft with a medical emergency on board or a flight involving medical supplies, vital organs and blood products may use this callsign as well. For more information, see this link:
Lifeguard and Priority Handling - Aviation Safety and Reporting System (NASA)
Why is there a delay in position reports?
The FAA recently imposed a mandatory delay in live air traffic data that is released to the general public.
Where can I get more information on Flight Explorer?
Please visit the Flight Explorer website. They offer PC-based software that can be used to track specific aircraft and with many more features. If you end up purchasing any Flight Explorer products, please mention that you heard about it first on FlightWeb.
FlightWeb
http://www.flightweb.com/staticpages/index.php/LG_FAQ