When must controllers issue wind shear reports to all departing and arriving aircraft?

Controllers must issue wind shear reports to all departing and arriving aircraft until it is broadcast on the Automated Terminal Information Service (ATIS). This procedure ensures that all aircraft operating in the vicinity of the airport are aware of any wind shear conditions that could affect their performance, particularly during takeoff and landing phases.

The reason this option is correct is that the ATIS is a continuous broadcast of recorded information that provides essential airport and weather information to pilots. While on-the-spot reporting of wind shear is crucial for safety, the transition of that information to ATIS allows pilots to receive updates as they prepare for departure or approach, ensuring more comprehensive awareness of current conditions.

The other options do not align with proper protocols for wind shear reporting. Requesting information only when prompted by pilots can lead to critical delays in communication. Relying solely on radar detection may not account for local conditions experienced on the ground. Lastly, waiting for ground teams to diagnose and report before issuing warnings could introduce unnecessary risk, as immediate awareness of dangerous conditions is paramount to ensuring safety during flight operations.