Who will notify the tower as soon as possible when the prevailing visibility at the official weather observation point decreases to less than 4 statute miles?

• A. ATC directives
• B. EUs with AMOS systems
• C. Weather technicians at augmented EUs
• D. Observing Aids for Visibility

Answer: (C)

When prevailing visibility at the official weather observation point drops to 4 statute miles or less, the responsibility for alerting the tower falls to the weather technicians assigned to augmented weather units. They are the hands-on observers who monitor visibility changes, verify data, and have direct, established channels to communicate critical weather updates to airfield operations. This ensures the tower receives prompt notice to adjust operations as needed for safety.

Automated AMOS systems and the observing aids provide data, but the notification duty is carried out by the human weather personnel at augmented units. ATC directives are issued by air traffic control to manage flights and may request updates, but they are not the ones who trigger the initial notification.