Visibility
Visibility is the greatest horizontal distance at which a specified target can be seen and identified. In aviation, visibility determines whether VFR flight can be conducted and whether an instrument approach can be commenced or continued. It is reported in METARs in statute miles (SM) or metres.
Types of Visibility
- Prevailing visibility: Greatest horizontal visibility observed over at least half the horizon; reported in METARs
- Flight visibility: Horizontal visibility from the cockpit; the pilot’s responsibility
- Ground visibility: Visibility reported from the aerodrome surface
- RVR: Runway Visual Range — specific to the runway; most relevant for low-visibility approaches
- Sector visibility: Reported when visibility differs significantly in different directions
VFR Visibility Minima
Controlled airspace (below 10,000 ft): 3 SM. Uncontrolled airspace: 1 SM (at or above 1,000 ft AGL); 2 SM (below 1,000 ft AGL). Special VFR: 1 SM. These are minimums — always fly with an appropriate safety buffer above minimums.
On the TC Written Exam
VFR visibility minima for different airspace classes and times of day are guaranteed exam material. Know all applicable minimums.