Within one hour before and after ETA, what is the minimum visibility related to fog or restriction?

• A. 2 statute miles
• B. 1 statute mile
• C. 4 statute miles
• D. 3 statute miles

Answer: (D)

The key idea is weather minimums in reduced visibility conditions around the expected arrival time. When fog or other visibility-restricting conditions are present, the required minimum flight visibility within one hour before and after the estimated time of arrival is 3 statute miles. This provides enough forward visibility to identify the runway environment and maintain safe approach and landing under IFR, even as conditions may vary within that hour.

Choosing a lower value (1 or 2 miles) wouldn’t give enough sight distance for safe maneuvering in fog, and a higher value (4 miles) isn’t the standard minimum in this scenario. If visibility is expected to dip below 3 miles in that window, plan would typically involve using an alternate airport or adjusting timing.