AIM ¶ 4-5-9 — FIS-B Weather Broadcast
AIM 4-5-9: FIS-B over 978 MHz UAT delivers cockpit weather and aeronautical info. Learn limitations, products, update intervals for checkride prep.
In Plain English
FIS-B (Flight Information Service-Broadcast) is a free, one-way ground-to-air broadcast delivered through the ADS-B network on the 978 MHz UAT data link. Properly equipped aircraft receive a cockpit display of weather and aeronautical information, but reception is line-of-sight within the ground station's service volume.
Key limitations every pilot must understand:
- FIS-B does not replace a preflight weather briefing or in-flight updates from FSS or ATC.
- It should not be the sole source of weather or aeronautical information.
- Be especially alert to the latency of NEXRAD imagery and the currency of NOTAMs/TFRs (NOTAM-D and FDC products are limited to those issued or effective within the past 30 days).
Products include METAR/SPECI, TAF, PIREPs, AIRMET/SIGMET, NEXRAD, winds/temps aloft, NOTAMs, TFRs, SUA status, lightning, turbulence, icing, and more — each with its own update interval (rate from source) and transmission interval (rebroadcast rate). For example, regional NEXRAD updates every 2 minutes, while CONUS NEXRAD rebroadcasts every 15 minutes.
Report FIS-B malfunctions to the nearest FSS by radio/phone or email [email protected] — include condition, time, altitude, location, aircraft type/call sign, and avionics version.
AIM Source Text
FAA AIM ¶ 4-5-94-5-9. 4-5-9. Flight Information Service- Broadcast (FIS-B)
Introduction. FIS-B is a ground broadcast service provided through the ADS-B Services network over the 978 MHz UAT data link. The FAA FIS-B system provides pilots and flight crews of properly equipped aircraft with a cockpit display of certain aviation weather and aeronautical information. FIS-B reception is line-of-sight within the service volume of the ground infrastructure. (See FIG 4-5-7 and FIG 4-5-8 .) Weather Products. FIS-B does not replace a preflight weather briefing from a source listed in paragraph 7-1-2 , FAA Weather Services, or inflight updates from an FSS or ATC. FIS-B information may be used by the pilot for the safe conduct of flight and aircraft movement; however, the information should not be the only source of weather or aeronautical information. A pilot should be particularly alert and understand the limitations and quality assurance issues associated with individual products. This includes graphical representation of next generation weather radar (NEXRAD) imagery and Notices to Airmen (NOTAMs)/temporary flight restrictions (TFRs). REFERENCE- AIM, Para 7-1-9 , Flight Information Services (FIS). Advisory Circular (AC) 00-63, Use of Cockpit Displays of Digital Weather and Aeronautical Information. Reports of FIS-B Malfunctions. Users of FIS-B can provide valuable assistance in the correction of malfunctions by reporting instances of undesirable system performance. Since FIS-B performance is monitored by maintenance personnel rather than ATC, report malfunctions to the nearest Flight Service Station (FSS) facility by radio or telephone, or by sending an email to the ADS-B help desk at [email protected]. Reports should include: Condition observed; Date and time of observation; Altitude and location of observation; Type and call sign of the aircraft; and Type and software version of avionics system. TBL 4-5-3 FIS−B Over UAT Product Update and Transmission Intervals Product Update Interval Transmission Interval (95%) Basic Product AIRMET As Available 5 minutes Yes AWW/WW As Available, then at 15 minute intervals for 1 hour 5 minutes No Ceiling As Available 10 minutes No Convective SIGMET As Available, then at 15 minute intervals for 1 hour 5 minutes Yes D-ATIS As Available 1 minute No Echo Top 5 minutes 5 minutes No METAR/SPECI 1 minute (where available), As Available otherwise 5 minutes Yes MRMS NEXRAD (CONUS) 2 minutes 15 minutes Yes MRMS NEXRAD (Regional) 2 minutes 2.5 minutes Yes NOTAMs-D/FDC As Available 10 minutes Yes NOTAMs-TFR As Available 10 minutes Yes PIREP As Available 10 minutes Yes SIGMET As Available, then at 15 minute intervals for 1 hour 5 minutes Yes SUA Status As Available 10 minutes Yes TAF/AMEND 6 Hours (±15 minutes) 10 minutes Yes Temperature Aloft 12 Hours (±15 minutes) 10 minutes Yes TWIP As Available 1 minute No Winds aloft 12 Hours (±15 minutes) 10 minutes Yes Lightning strikes 5 minutes 5 minutes Yes Turbulence 1 minute 15 minutes Yes Icing, Forecast Potential (FIP) 60 minutes 15 minutes Yes Cloud tops 30 minutes 15 minutes Yes 1 Minute AWOS 1 minute 10 minutes No Graphical-AIRMET As Available 5 minutes Yes Center Weather Advisory (CWA) As Available 10 minutes Yes Temporary Restricted Areas (TRA) As Available 10 minutes Yes Temporary Military Operations Areas (TMOA) As Available 10 minutes Yes The Update Interval is the rate at which the product data is available from the source. The Transmission Interval is the amount of time within which a new or updated product transmission must be completed (95%) and the rate or repetition interval at which the product is rebroadcast (95%). The transmission and update intervals for the expanded set of basic meteorological products may be adjusted based on FAA and vendor agreement on the final product formats and performance requirements. NOTE- Details concerning the content, format, and symbols of the various data link products provided should be obtained from the specific avionics manufacturer. NOTAM-D and NOTAM-FDC products broadcast via FIS-B are limited to those issued or effective within the past 30 days.
Oral Exam Questions a DPE Might Ask
Q1What frequency and data link does FIS-B use, and what is its reception range?
Per AIM 4-5-9, FIS-B is broadcast over the 978 MHz UAT data link through the ADS-B Services network, and reception is line-of-sight within the service volume of the ground infrastructure.
Q2Can FIS-B be used as your sole source of preflight weather information?
No. Per AIM 4-5-9, FIS-B does not replace a preflight briefing from an approved source or in-flight updates from FSS/ATC. It may be used for safe conduct of flight, but should not be the only source of weather or aeronautical information, and pilots must understand product limitations such as NEXRAD imagery latency and NOTAM/TFR currency.
Q3How do you report a suspected FIS-B malfunction, and what information should the report include?
Per AIM 4-5-9, since FIS-B performance is monitored by maintenance personnel rather than ATC, report malfunctions to the nearest FSS by radio or telephone, or email the ADS-B help desk at [email protected]. Include the condition observed; date and time; altitude and location; aircraft type and call sign; and avionics type and software version.
Related Paragraphs in AIM Chapter 4