Plain English Meaning

It is a measurement of how far a pilot can see down the runway, taken by a sensor placed near the spot where the aircraft will touch down. This is the visibility number that usually decides whether an approach can be flown to its minimums.

Full Definition

The Runway Visual Range value reported from a transmissometer or visibility sensor located near the touchdown zone of an instrument runway, representing the horizontal distance a pilot can expect to see down the runway from the approach end. TDZ RVR is the controlling RVR value for most precision approach minima, including CAT I, CAT II, and CAT III operations.