The wind direction indicator is to be illuminated as follows.

The wind direction indicator is to be illuminated as follows.

• A. internally
• B. externally
• C. both
• D. not at all

Answer: (B)

Visibility of the wind direction indicator at night or in low-visibility conditions hinges on how it’s illuminated. The outside lighting makes the indicator’s silhouette and orientation clearly visible to pilots from distance, regardless of the interior lighting or condition inside the housing. Illuminating from outside ensures the mark is bright on the exterior surface where it’s supposed to be seen, which is essential for quick recognition during approach or taxi. Lighting inside the enclosure wouldn’t reliably show the direction to aircraft and could be blocked by the housing or create inconsistent glare. Lighting both is unnecessary and wasteful, while not lighting it at all would leave the indicator invisible when it’s most needed.

Visibility of the wind direction indicator at night or in low-visibility conditions hinges on how it’s illuminated. The outside lighting makes the indicator’s silhouette and orientation clearly visible to pilots from distance, regardless of the interior lighting or condition inside the housing. Illuminating from outside ensures the mark is bright on the exterior surface where it’s supposed to be seen, which is essential for quick recognition during approach or taxi. Lighting inside the enclosure wouldn’t reliably show the direction to aircraft and could be blocked by the housing or create inconsistent glare. Lighting both is unnecessary and wasteful, while not lighting it at all would leave the indicator invisible when it’s most needed.