Which is more controlling during flight operations: RVR or visibility in statute miles?

RVR, or Runway Visual Range, is generally considered more controlling during flight operations compared to visibility measured in statute miles. RVR provides a more precise measurement of how far a pilot can see down the runway, which is crucial for takeoffs and landings, particularly in low visibility conditions.

When it comes to approaches and landings, pilots must maintain a clear view of the landing zone and the specific runway environment. RVR takes into account factors such as atmospheric conditions, runway lighting, and other elements that can affect visibility immediately ahead on the runway. Thus, it offers a tailored metric that is more relevant to the operational needs of flight crews.

Visibility in statute miles is a broader measure that may not reflect the actual conditions impacting runway use. It does not provide the same level of detail regarding the operational environment close to the aircraft, which may lead to inconsistencies in flight operations, especially if the visibility is reported as being good in general but not sufficient for safe landing on a specific airport runway.

Therefore, RVR is the more controlling metric because it aligns closely with the critical needs for safety when pilots are executing landings and takeoffs in varying visibility conditions.