Controllers must advise pilots of hazardous weather that may impact operations within how many nautical miles of their sector or area of jurisdiction?

• A. 25 NM
• B. 50 NM
• C. 100 NM
• D. 150 NM

Answer: (D)

The key idea here is giving pilots enough lead time to react to weather hazards. When hazardous weather could affect a flight, controllers provide the pilots with advisory information that covers a wide area around their sector, so the crew has time to plan deviations, changes in altitude, or alternate routes, and so ATC can coordinate traffic flow accordingly.

Choosing the largest radius among the options ensures pilots receive this warning well before the weather actually impacts their path, which helps prevent late evasive actions and keeps traffic moving safely and smoothly. Shorter radii wouldn’t give as much lead time and could force abrupt decisions or delays.

In practice, while pilots rely on SIGMETs, AIRMETs, PIREPs, and radar data, the explicit advisory distance is set large enough to maximize safety and operational flexibility, hence the larger radius is preferred over the smaller ones.