Weather Awareness; Weather Awareness; Data Transmission Limitations; Line Of Sight Reception - Garmin GPS 175 Pilot's Manual

Weather Awareness

WARNING
DO NOT RELY SOLELY ON DATALINK WEATHER FOR WEATHER
INFORMATION. DATALINK WEATHER PROVIDES A SNAPSHOT IN TIME.
IT MAY NOT ACCURATELY REFLECT THE CURRENT WEATHER
SITUATION.
NOTE
Datalink weather is not intended to replace weather briefings or in-flight
weather reports from AFSS or ATC.
The FAA provides FIS-B as a Surveillance and Broadcast Service operating on the UAT
(978 MHz) frequency band. FIS-B uses a network of FAA-operated ground-based
transceivers to transmit weather datalink information to the aircraft's receiver on a
scheduled continuous basis.
The Flight Information Service-Broadcast (FIS-B) Weather service is freely available for
aircraft equipped with a capable datalink universal access transceiver (UAT). Ground
stations provide uninterrupted services for the majority of the contiguous U.S.,
Hawaii, Guam, Puerto Rico, and parts of Alaska. No weather subscription service is
required. For the latest FAA ground station coverage information, visit:
www.faa.gov/nextgen/programs/adsb/
5.1

Data Transmission Limitations

FIS-B broadcasts provide weather data in a repeating cycle which may take several
minutes to completely transmit all available weather data. Therefore, not all weather
data may be immediately present upon initial FIS-B signal acquisition.
5.1.1

Line of Sight Reception

To receive FIS-B weather information, the aircraft's datalink receiver must be within
range and line-of-sight of an operating ground-based transceiver. Reception may be
affected by altitude, terrain, and other factors. Per the FAA, much of the United
States has FIS-B In airborne coverage at and above 3,000 feet AGL. Terminal
coverage is available at altitudes below 3,000 feet AGL and is available when flying
near approximately 235 major U.S. airports. Surface coverage allows FIS-B ground
reception at approximately 36 major U.S. airports.
190-02207-02 Rev. 1 GPS 175/GNX 375 Pilot's Guide
Hazard Awareness
5-3