When conducting an approach with an ALS out of service, what should the minimum visibility be raised to?

When conducting an approach with the Approach Lighting System (ALS) out of service, the minimum visibility requirement must be raised to 1/2 statute mile. This adjustment is necessary because the ALS plays a significant role in aiding pilots during the final stages of an approach, particularly under low visibility conditions. It enhances the pilot's ability to see and identify the runway, especially at night or in adverse weather.

With the ALS out of service, the absence of this visual aid means that pilots have less support in maintaining orientation and judging distances during landing. Therefore, raising the visibility minimum is a precautionary measure to ensure that pilots have sufficient visual reference to safely conduct the approach and landing. Maintaining safety standards is crucial, and this adjustment helps mitigate the increased risk associated with reduced visual aids.