Fis-B Weather - Garmin GTN 650 Series Pilot's Manual Upgrade Supplement

5.7

FIS-B Weather

The Flight Information Services (FIS-B) function is capable of displaying text
and graphic weather information with GDL 88 installations. No subscription for
FIS-B services is required with the GDL 88.
The FIS-B Function is a graphic weather display capable of displaying
graphical weather information on UAT equipped installations. Graphical data is
overlaid on the map indicating the rainfall detected by ground based radar for a
specific area. Colors are used to identify the different NEXRAD echo intensities
(reflectivity) measured in dBZ (decibels of Z). "Reflectivity" (designated by the
letter Z) is the amount of transmitted power returned to the radar receiver.
The dBZ values increase as returned signal strength increases. Precipitation
intensity is displayed using colors corresponding to the dBZ values. Review the
Limitations section in the front of this guide for the limitations that apply to the
FIS-B data. An example of how rainfall data is color coded follows:
The FIS-B Function is based on a ground-to-air data link and requires that
the appropriate ground systems are broadcasting weather data and the aircraft is
within reception range of the Ground Broadcast Transceiver (GBT).
GTN 650/750 Series SW V3.00 Upgrade Supplement 190- 01007-05 Rev A
Figure 5-45 FIS-B Weather Precipitation Legend
67