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 distributed 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.
Since 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 follows: 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, Lockheed Martin, Direct User Access Terminal System (DUATS II)) 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 (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.