1-5 operating on instrument flight rules (IFR) flight plans within controlled airspace, principally during the en route phase of flight. When equipment capabilities and controller workload permit, certain advisory/assistance services may be provided to visual flight rules (VFR) aircraft.
En route controllers become familiar with pertinent weather information and stay aware of current weather information needed to perform ATC duties. En route controllers advise pilots of hazardous weather that may impact operations within 150 nautical miles (NM) of the controller’s assigned sector(s), and may solicit PIREPs from pilots.
1.2.3 Airport Traffic Control Tower (ATCT) and Terminal Radar Approach Control (TRACON).
An ATCT is a terminal facility that uses air/ground communications, visual signaling, and other devices to provide ATC services to aircraft operating in the vicinity of an airport or on the movement area.
Terminal controllers become familiar with pertinent weather information and stay aware of current weather information needed to perform ATC duties. Terminal controllers advise pilots of hazardous weather that may impact operations within 150 NM of the controller’s assigned sector or area of jurisdiction and may solicit PIREPs from pilots.
ATCTs and TRACONs may opt to broadcast hazardous weather information alerts only when any part of the area described is within 50 NM of the airspace under the ATCT’s jurisdiction.
The tower controllers are also properly certified and act as official weather observers, as required.
An automated terminal information service (ATIS) is a continuous broadcast of recorded information in selected terminal areas. Its purpose is to improve controller effectiveness and to relieve frequency congestion by automating the repetitive transmission of non-controlled airport/terminal area and meteorological information.
1.2.4 Flight Service Station (FSS).
FSSs provide pilot weather briefings, en route weather, receive and process IFR and VFR flight plans, solicit and disseminate pilot reports and urgent pilot reports, relay ATC clearances, and issue Notices to Airmen (NOTAM). They also provide assistance to lost aircraft and aircraft in emergency situations, as well as conduct VFR search and rescue services.
1.3 Dissemination of Aviation Weather Products.
The ultimate users of aviation weather services are pilots, aircraft dispatchers, and air traffic management (ATM) and air traffic controllers. Maintenance personnel may use the service to keep informed of weather that could cause possible damage to unprotected aircraft.
Pilots contribute to and use aviation weather services. PIREPs help other pilots, dispatchers, briefers, and forecasters as an observation of current conditions.
1-6 In the interest of safety and in compliance with Title 14 of the Code of Federal Regulations (14 CFR), all pilots should get a complete weather briefing before each flight. The pilot is responsible for ensuring he or she has all information needed to make a safe flight.
1.3.1 Weather Briefings.
Prior to every flight, pilots should gather all information vital to the nature of the flight.
This includes a weather briefing obtained by the pilot from an approved weather source, via the Internet, and/or from an FSS specialist.
The FSS’ purpose is to serve the aviation community. Pilots should not hesitate to ask questions and discuss factors they do not fully understand. The briefing should be considered complete only when the pilot has a clear picture of what weather to expect.
Pilots should also make a final weather check immediately before departure, when possible.
To provide an appropriate weather briefing, specialists need to know which of the three types of briefings is needed—standard, abbreviated, or outlook. Other necessary information includes whether the flight will be conducted with VFR or IFR, aircraft identification and type, departure point, estimated time of departure, flight altitude, route of flight, destination, and estimated time en route. If the briefing updates previously received information, the time of the last briefing is also important. This allows the briefer to provide only pertinent data.
The briefer enters this information into the FAA’s flight plan system. The briefer also notes the type of weather briefing provided. If necessary, the information can be referenced later to file or amend a flight plan. It is also used when an aircraft is overdue or is reported missing. Internet data is time-stamped and archived for 15 days. Voice recordings are retained for 45 days.
1.3.1.1 Standard Briefing.
A standard briefing provides a complete weather picture and is the most detailed of all briefings. This type of briefing should be obtained prior to the departure of any flight and should be used during flight planning. A standard briefing provides the following information (if applicable to the route of flight) in sequential order:
• Adverse Conditions. This includes information about adverse conditions that may influence a decision to cancel or alter the route of flight. Adverse conditions include significant weather (e.g., thunderstorms, aircraft icing, turbulence, windshear, mountain obscuration, and areas of current and forecasted IFR conditions) and other important items, such as airport/runway closings, air traffic delays, and temporary flight restrictions (TFR).
• VFR Flight NOT RECOMMENDED (VNR). If the weather for the route of flight is below VFR minimums, or if it is doubtful the flight can be made under VFR conditions due to the forecasted weather, the briefer
1-7 may state that VFR is not recommended. The pilot can then decide whether or not to continue the flight under VFR, but this advisory should be weighed carefully. This advisory is not provided via the Internet.
• Synopsis. The synopsis is an overview of the larger weather picture.
Fronts and major weather systems along or near the route of flight and weather that may affect the flight are provided.
• Current Conditions. This portion of the briefing contains the current surface weather observations, PIREPs, and satellite and radar data along the route of flight. If the departure time is more than 2 hours away, current conditions will not be included in the briefing.
• En Route Forecast. The en route forecast is a summary of the weather forecast for the proposed route of flight.
• Destination Forecast. The destination forecast is a summary of the expected weather for the destination airport at the estimated time of arrival (ETA).
• Winds and Temperatures Aloft. Winds and temperatures aloft is a forecast of the winds at specific altitudes along the route of flight.
However, the temperature information is provided only on request.
• NOTAMs. This portion supplies NOTAM information that has not been published in the NOTAM publication, but is pertinent to the route of flight. Published NOTAM information is provided during the briefing only on request.
• Prohibited Areas and Special Flight Rules Areas (SFRA). Information on Prohibited Areas P-40 and P-56, and the SFRA for Washington, D.C.
are given when appropriate to the route of flight.
• ATC Delays. This is an advisory of any known ATC delays that may affect the flight.
• Other Information. Any additional information requested is also provided at this time.
1.3.1.2 Abbreviated Briefing.
An abbreviated briefing is a shortened version of the standard briefing. It should be requested when a departure has been delayed or when specific weather information is needed to update a previous standard briefing. When this is the case, the weather specialist needs to know the time and source of the previous briefing so he or she does not inadvertently omit the necessary weather information.
1.3.1.3 Outlook Briefing.
An outlook briefing should be requested when a planned departure is 6 or more hours away. It provides initial forecast information that is limited in scope due to the timeframe of the planned flight. This type of briefing is a
1-8 good source of flight planning information that can influence decisions regarding route of flight, altitude, and ultimately the “go, no-go” decision. A follow-up standard briefing prior to departure is advisable, since an outlook briefing generally only contains information based on weather trends and existing weather in geographical areas at or near the departure airport.
1.3.2 Pilot Briefing via the Internet.
1.3.2.1 Aviation Digital Data Service (ADDS).
ADDS is a joint effort of the FAA, NOAA, and the National Center for Atmospheric Research (NCAR). ADDS provides text, digital, and graphical forecasts, analyses, and observations of aviation-related weather variables.
1.3.3 Hazardous In-Flight Weather Advisory Service (HIWAS).
HIWAS is a national program for broadcasting hazardous weather information continuously over selected Navigational Aids (NAVAID). The broadcasts include advisories such as AIRMETs, SIGMETS, Convective SIGMETs, and urgent PIREPs.
These broadcasts are only a summary of the information, and pilots should contact an FSS for detailed information.
The HIWAS broadcast area is defined as the area within 150 NM of HIWAS outlets.
HIWAS broadcasts are not interrupted or delayed, except for emergency situations, when an aircraft requires immediate attention, or for reasonable use of the voice override capability on specific HIWAS outlets in order to use the limited remote communications outlet (RCO) to maintain en route communications. The service is provided 24 hours a day. An announcement is made for no hazardous weather advisories.
Hazardous weather information is recorded if it is occurring within the HIWAS broadcast area. The broadcast includes the following elements:
• A statement of introduction including the appropriate area(s) and a recording time.
• A summary of Convective SIGMETs, SIGMETs, AIRMETs, Urgent PIREPs, Aviation Watch Notification Messages (SAW), Center Weather Advisories, and any other weather, such as isolated thunderstorms that are rapidly developing and increasing in intensity, or low ceilings and visibilities that are becoming widespread, which are considered significant and are not included in a current hazardous weather advisory.
• A request for PIREPs, if applicable.
• A recommendation to contact FSS for additional details concerning hazardous weather.
Once the HIWAS broadcast is updated, an announcement will be made once on all communications/NAVAID frequencies, except emergency and navigational frequencies already dedicated to continuous broadcast services. In the event a HIWAS broadcast area is out of service, an announcement is made on all communications/NAVAID frequencies,
1-9 except on emergency and navigational frequencies already dedicated to continuous broadcast services.
1.3.4 Flight Information Service-Broadcast (FIS-B).
FIS-B over universal access transceiver (UAT) data-link service provides Aeronautical Information (AI) to the flightdeck for aircraft operating in the NAS. These products are broadcast over the Automatic Dependent Surveillance-Broadcast (ADS-B) UAT link so pilots have timely information of regional weather and NAS status/changes that might affect flight. It is critical that pilots understand that FIS-B meteorological information and AI products provide strategic information to the flight deck that enhances a preflight briefing. FIS-B AI products do not include all NOTAMs. FIS-B NOTAM information is limited to the past 30 days. As a result, FIS-B AI may not include all NOTAMs that a preflight briefing includes. The pilot in command (PIC) is responsible for reviewing all necessary information prior to flight. Therefore, AI information obtained via FIS-B may not be relied upon for a thorough preflight briefing. For additional information on standard briefing, refer to the Aeronautical Information Manual (AIM), Chapter 7, Safety of Flight, Subparagraph 7- 1-4b, Weather Products.
The following list represents the initial suite of textual and graphical products available through FIS-B and provided free-of-charge. This advisory circular (AC) and AC 00-63, Use of Cockpit Displays of Digital Weather and Aeronautical Information, contain det ailed information concerning FIS-B meteorological products. AIM Chapter 3, Airspace; Chapter 4, Air Traffic Control; and Chapter 5, Air Traffic Procedures contain information on Special Use Airspace (SUA), TFR, and NOTAM products.
• Text: METAR and SPECI;
• Text: PIREP;
• Text: Winds and Temperatures Aloft;
• Text: TAF;
• Text: NOTAM Distant and Flight Data Center;
• Text/Graphic: AIRMET;
• Text/Graphic: SIGMET;
• Text/Graphic: Convective SIGMET;
• Text/Graphic: SUA;
• Text/Graphic: TFR NOTAM;
• Graphic: Next generation weather radar (NEXRAD) Composite Reflectivity Products (Regional and National);
• Lightning;
• Turbulence;
• Cloud Tops;
1-10
• Icing;
• Graphical AIRMETs (G-AIRMET); and
• CWA.
Users of FIS-B should familiarize themselves with the operational characteristics and limitations of the system, including: system architecture, service environment, product lifecycles, modes of operation, and indications of system failure.
Up date intervals are defined as the rate at which the product data is available from the source for transmission. Transmission intervals are defined as the amount of time within which a new or updated product transmission must be completed and/or the rate or repetition interval at which the product is rebroadcast. Table 1-1, FIS-B Over UAT Product Update and Transmission Intervals, provides update and transmission intervals for each product.
Where applicable, FIS-B products include a look-ahead range expressed in nautical miles for three service domains: Airport Surface, Terminal Airspace, and En route/Gulf of Mexico. Table 1-2, Product Parameters for Low/Medium/High Altitude Tier Radios, provides service domain availability and look-ahe ad ranging for each FIS-B product.
Prior to using this capability, users should familiarize themselves with the operation of FIS-B avionics by referencing the applicable user’s guides. Users should obtain guidance concerning the interpretation of information displayed from the appropriate avionics manufacturer.
Us ers should report FIS-B malfunctions not attributed to aircraft system failures or covered by active NOTAM via the ADS-B/Traffic Information Services-Broadcast (TIS-B)/FIS-B Problem Report on the following website:
http://www.faa.gov/exit/?pageName=this%20form&pgLnk=http%3A%2F%2Fgoo%2Egl %2Fforms%2FisWDKYpYYv. Users may also report malfunctions by submitting FAA Form 8740-5, Safety Improvement Report, via mail, fax, or email to your local F light District Standards Office (FSDO) Safety Program Manager (SPM).
1-11 Table 1-1. FIS-B Over UAT Product Update and Transmission Intervals Product FIS-B Over UAT Service Update Interval1 FIS-B Service Transmission Interval2 AIRMET As available 5 minutes Convective SIGMET As available 5 minutes METARs/SPECIs 1 minute/as available 5 minutes NEXRAD Composite Reflectivity (CONUS) 15 minutes 15 minutes NEXRAD Composite Reflectivity (Regional) 5 minutes 2.5 minutes NOTAMs–D/FDC/TFR As available 10 minutes PIREP As available 10 minutes SIGMET As available 5 minutes Special Use Airspace Status As available 10 minutes TAF/AMEND 6 hours/as available 10 minutes Temperature Aloft 12 hours 10 minutes Winds Aloft 12 hours 10 minutes Lightning Strikes 5 minutes 5 minutes Turbulence 15 minutes 15 minutes Icing Forecasts 15 minutes 15 minutes Cloud Tops 15 minutes 15 minutes Graphical AIRMETS 00Z,03Z, 06Z, 09Z/12 hr forecasts 3 hour Center Weather Advisories As available As available
1. The Update Interval is the rate at which the product data is available from the source.
2. The Transmission Interval is the amount of time within which a new or updated product transmission must be completed and the rate or repetition interval at which the product is rebroadcast.
3. Notice to Airmen-Distant (NOTAM-D) and Notice to Airmen-Flight Data Center (NOTAM-FDC) products broadcast via FIS-B are limited to those issued or effective within the past 30 days.
1-12 Table 1-2. Product Parameters for Low/Medium/High Altitude Tier Radios Product Surface Radios Low Altitude Tier Medium Altitude Tier High Altitude Tier
CONUS NEXRAD N/A CONUS NEXRAD not provided
CONUS NEXRAD imagery
CONUS NEXRAD imagery Winds & Temps Aloft 500 NM look-ahead range 500 NM look-ahead range 750 NM look-ahead range 1,000 NM look-ahead range METAR 100 NM look-ahead range 250 NM look-ahead range 375 NM look-ahead range CONUS: CONUS Class B & C airport METARs and 500 NM look-ahead range Outside of CONUS:
500 NM look-ahead range TAF 100 NM look-ahead range 250 NM look-ahead range 375 NM look-ahead range CONUS: CONUS Class B & C airport TAFs and 500 NM look-ahead range Outside of CONUS:
500 NM look-ahead range
AIRMET, SIGMET, PIREP and Special Use Airspace/SAA 100 NM look-ahead range.
PIREP/SUA is N/A 250 NM look-ahead Range 375 NM look-ahead range 500 NM look-ahead range Regional NEXRAD 150 NM look-ahead range 150 NM look-ahead range 200 NM look-ahead range 250 NM look-ahead range NOTAMs–D/FDC/TFR 100 NM look-ahead range 100 NM look-ahead range 100 NM look-ahead range 100 NM look-ahead range Lightning Strikes N/A 150 NM look-ahead range 200 NM look-ahead range 250 NM look-ahead range Turbulence N/A 150 NM look-ahead range 200 NM look-ahead range 250 NM look-ahead range Icing Forecasts N/A 150 NM look-ahead range 200 NM look-ahead range 250 NM look-ahead range Cloud Tops N/A 150 NM look-ahead range 200 NM look-ahead range 250 NM look-ahead range Graphical AIRMETS N/A 250 NM look-ahead range 375 NM look-ahead range 500 NM look-ahead range Center Weather Advisories N/A 250 NM look-ahead range 375 NM look-ahead range 500 NM look-ahead range Users should obtain guidance concerning the content, format, and symbology of individual FIS-B products from the manufacturer of the avionics equipment used to receive and display them.
1-13
1.3.5 Operational Use of FIS-B Products.
FIS-B information may be used by the pilot for the safe conduct of flight and aircraft movement. However, FIS-B does not replace a thorough preflight briefing that may be from one or several Meteorological Information and AI sources. Pilots are encouraged, but not required, to use the dispatch/System Operations Control (SOC) (if applicable), or access an FSS via telephone. Title 14 CFR part 91, § 91.103 requires the pilot in command (PIC) to be familiar with all available information concerning that flight. A pil ot should be particularly alert and understand the limitations and quality assurance (QA) issues associated with individual products. This includes graphical representation of NEXRAD imagery and NOTAM/TFR.
2-1 CHAPTER 2. AVIATION WEATHER PRODUCT POLICY The demand for new and improved aviation weather products continues to grow, and with new products introduced to meet the demand, some confusion has resulted in the aviation community regarding the relationship between regulatory requirements and new weather products.
This chapter will clarify that relationship by providing:
• Policy guidance for using aviation weather products,
• Descriptions of the types of aviation weather information, and
• Categorization of the sources of aviation weather information.
2.1 Use of Aviation Weather Products.
This AC describes the weather products distributed by the NWS. Pilots and operators using the Internet to access weather from a third-party vendor should request and/or review an appropriate description of services and provider disclosure. This should include, but is not limited to, the type of weather product (i.e., current weather or forecasted weather), the currency of the product (i.e., product issue and valid times) and the relevance of the product. Pilots and operators should be cautious when using unfamiliar weather products. When in doubt, consult with a Flight Service Specialist.
Note that the FAA does not approve or qualify Internet providers of aviation weather service.
The development of new weather products, coupled with the termination of some legacy textual and graphical products, may create confusion between regulatory requirements and the new products. All flight-related aviation weather decisions must be based on all available pertinent weather products. As every flight is unique and the weather conditions for that flight vary hour-by-hour, day-to-day, multiple weather products may be necessary to meet aviation weather regulatory requirements. Many new weather products have a precautionary use statement displayed that details the proper use or application of the specific product.
2.2 Types of Aviation Weather Information.
The FAA has identified the following three distinct types of weather information that may be needed to conduct aircraft operations: observations, analyses, and forecasts.
2.2.1 Observations.
Observations are raw weather data collected by sensor(s). The observations can either be in situ (i.e., surface or airborne) or remote (i.e., weather radar, satellite, profiler, and lightning).
2.2.2 Analyses.
Analyses of weather information are an enhanced depiction and/or interpretation of observed weather data. Examples of these types of analyses can be seen in paragraph 4.1.1. Another type of analysis is the representation of an atmospheric variable
(e.g., temperature, ceiling height, and visibility) derived from a finite set of irregularly
2-2 dis tributed observations onto a regular grid. See the figures in paragraph 4.2 for examples.
2.2.3 Forecasts.
Forecasts are the predictions of the development and/or movement of weather phenomena based on meteorological observations and various mathematical models.
In-flight weather advisories, including Terminal Aerodrome Forecast (TAF), significant meteorological information (SIGMET), Convective SIGMETs, Airman’s Meteorological Information (AIRMET), Center Weather Advisories (CWA), and Meteorological Impact Statements (MIS) are considered forecast weather information products.
2.3 Categorizing Aviation Weather Sources.
The regulations pertaining to aviation weather reflect that, historically, the Federal Government was the only source of aviation weather information. That is, the FAA and NWS, or their predecessor organizations, were solely responsible for the collection and dissemination of weather data, including forecasts. Thus, the term “approved source(s)” referred exclusively to the Federal Government. The Federal Government is no longer the only source of weather information, due to the growing sophistication of aviation operations and scientific and technological advances.
Si nce all three types of weather information defined in paragraph 2.2 are not available from all sources of aviation weather information, the FAA has categorized the sources as fol lows: Federal Government and commercial weather information providers.
2.3.1 Federal Government.
The FAA and NWS collect weather observations. The NWS analyzes the observations and produces forecasts, including in-flight aviation weather advisories (e.g., SIGMETs).
The FAA and NWS disseminate meteorological observations, analyses, and forecast products through a variety of systems. The Federal Government is the only approval authority for sources of weather observations (e.g., contract towers and airport operators).
Commercial weather information providers contracted by the FAA to provide weather observations (e.g., contract towers and Lockheed Martin) are included in the Federal Government category of approved sources by virtue of maintaining required technical and quality assurance standards under FAA and NWS oversight.
2.4 Commercial Weather Information Providers.
Commercial weather information providers are a major source of weather products for the aviation community. In general, they produce proprietary weather products based on NWS information with formatting and layout modifications, but no material changes to the weather information itself. This is also referred to as “repackaging.”
In other cases, commercial providers produce forecasts, analyses, and other proprietary weather products which may substantially differ from the information contained in NWS-produced products. Operators who desire to use products prepared by a commercial weather provider, as opposed to using products that are simply repackaged, may require FAA approval. This approval is granted under the provisions in Operations Specification
2-3 (OpSpec) paragraph A010. Please provide which services and products you are contemplating using, to include the appropriate description of the service. This should include, but is not limited to:
• The type of weather product (e.g., current weather or forecast weather);
• The currency of the product (i.e., product issue and valid times); and
• The relevance of the product.
Pilots and operators should be cautious when using unfamiliar products, or products not supported by FAA/NWS technical specifications.