Weather reporting facilities

This regulation establishes weather information requirements for Part 121 air carriers operating domestic or flag routes.

Airlines must demonstrate that adequate weather reporting services exist along their routes to support safe operations. When using weather reports to make operational decisions (like dispatch or flight planning), the reports must come from approved sources: within the continental U.S., this means the National Weather Service or NWS-approved sources; outside the continental U.S., the FAA must approve the source.

Forecasts used for flight control must be based on these approved weather reports. Additionally, airlines must implement an FAA-approved system for obtaining information about hazardous weather phenomena—such as clear air turbulence, thunderstorms, and low-altitude wind shear—that could affect safety along their routes and at their airports.

In practice, this ensures airlines base critical operational decisions on reliable, vetted weather information rather than unverified sources, reducing weather-related risks in commercial aviation.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*