What visibility requirement is needed under a Special VFR clearance?

Under a Special VFR (SVFR) clearance, the visibility requirement is specifically set at 1 mile or more. This is designed to allow pilots to operate in lower visibility conditions than normally permitted for Visual Flight Rules (VFR), which typically require greater visibility and cloud clearance.

The purpose of this requirement is to provide pilots with the opportunity to conduct operations in situations where they might otherwise be restricted due to limited visibility but still maintain enough visual reference to ensure safe flight. This implies that even though the visibility is reduced, it is still considered safe under certain conditions, thus allowing for greater operational flexibility while maintaining safety standards.

The other options suggest higher visibility requirements, which are not applicable to SVFR. In standard VFR conditions, the visibility generally required is above 3 miles, depending on airspace classification, and situations involving visibility under 1 mile typically fall into Instrument Flight Rules (IFR) territory. However, the specific SVFR criterion uniquely accommodates lower visibility conditions while ensuring pilots can still safely navigate and maintain visual separation from other aircraft.