How far must controllers advise pilots of hazardous weather impacts?

The requirement for controllers to advise pilots of hazardous weather impacts within 150 nautical miles (NM) of their sector is based on the principle of ensuring safety and providing comprehensive situational awareness to pilots. By alerting pilots to hazardous weather that far out, controllers enhance the ability of flight crews to make informed decisions regarding their flight paths and operational strategies.

This distance allows adequate time for pilots to adjust their route, altitude, or other flight parameters to avoid severe weather conditions, thereby improving safety and potentially preventing accidents. The 150 NM radius takes into consideration the typical range of aircraft operations, allowing enough lead time for pilots to react and for any necessary coordination with air traffic control and other operational units.

In contrast, the shorter distances mentioned in other options may not provide sufficient warning for pilots, reducing their ability to effectively manage their flight in response to hazardous weather conditions that could impact safety. Therefore, the chosen answer reflects the most comprehensive measure to ensure full awareness and safety regarding hazardous weather in aviation operations.