Airborne weather radar equipment requirements

This regulation requires Part 121 operators to install approved airborne weather radar on transport category airplanes (except C-46s) and newer nontransport category airplanes. The key operational requirement is that you cannot dispatch a flight under IFR or night VFR when thunderstorms or detectable hazardous weather is reasonably expected along the route unless the radar is working properly.

If the radar fails during flight, you must follow procedures in your operations manual. The regulation exempts flights operating solely within Hawaii, within a defined area of Alaska and western Canada, and training/test/ferry flights. Notably, weather radar does not require a backup electrical power supply, unlike some other required equipment.

This matters because it ensures Part 121 aircraft can detect and avoid severe weather when conditions suggest such weather may be present, directly affecting dispatch decisions and flight safety.

*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.*