Pilot/Controller Glossary

conditions are at or below VFR minimums. It does
not abrogate the pilot"s authority to make his/her own
decision.
VFR-ON-TOP- ATC authorization for an IFR
aircraft to operate in VFR conditions at any
appropriate VFR altitude (as specified in 14 CFR and
as restricted by ATC). A pilot receiving this
authorization must comply with the VFR visibility,
distance from cloud criteria, and the minimum IFR
altitudes specified in 14 CFR Part 91. The use of this
term does not relieve controllers of their responsibility to separate aircraft in Class B and Class C airspace
or TRSAs as required by FAA Order JO 7110.65.
VFR TERMINAL AREA CHARTS-
(See AERONAUTICAL CHART.)

VFR WAYPOINT-
(See WAYPOINT.)

VHF-
(See VERY HIGH FREQUENCY.)

VHF OMNIDIRECTIONAL RANGE/TACTICAL
AIR NAVIGATION-
(See VORTAC.)

VIDEO MAP- An electronically displayed map on
the radar display that may depict data such as airports,
heliports, runway centerline extensions, hospital
emergency landing areas, NAVAIDs and fixes,
reporting points, airway/route centerlines, boundaries, handoff points, special use tracks, obstructions,
prominent geographic features, map alignment
indicators, range accuracy marks, and/or minimum
vectoring altitudes.
VISIBILITY- The ability, as determined by
atmospheric conditions and expressed in units of
distance, to see and identify prominent unlighted
objects by day and prominent lighted objects by
night. Visibility is reported as statute miles, hundreds
of feet or meters.
(Refer to 14 CFR Part 91.)
(Refer to AIM.)

a. Flight Visibility- The average forward horizontal distance, from the cockpit of an aircraft in flight,
at which prominent unlighted objects may be seen
and identified by day and prominent lighted objects
may be seen and identified by night.
b. Ground Visibility- Prevailing horizontal visibility near the earth"s surface as reported by the

United States National Weather Service or an
accredited observer.
c. Prevailing Visibility- The greatest horizontal
visibility equaled or exceeded throughout at least half
the horizon circle which need not necessarily be
continuous.
d. Runway Visual Range (RVR)- An instrumentally derived value, based on standard calibrations,
that represents the horizontal distance a pilot will see
down the runway from the approach end. It is based
on the sighting of either high intensity runway lights
or on the visual contrast of other targets whichever
yields the greater visual range. RVR, in contrast to
prevailing or runway visibility, is based on what a
pilot in a moving aircraft should see looking down the
runway. RVR is horizontal visual range, not slant
visual range. It is based on the measurement of a
transmissometer made near the touchdown point of
the instrument runway and is reported in hundreds of
feet. RVR, where available, is used in lieu of
prevailing visibility in determining minimums for a
particular runway.
1. Touchdown RVR- The RVR visibility
readout values obtained from RVR equipment
serving the runway touchdown zone.
2. Mid-RVR- The RVR readout values obtained
from RVR equipment located midfield of the runway.
3. Rollout RVR- The RVR readout values
obtained from RVR equipment located nearest the
rollout end of the runway.

ICAO term FLIGHT VISIBILITY.)
ICAO term GROUND VISIBILITY.)
ICAO term RUNWAY VISUAL RANGE.)
ICAO term VISIBILITY.)

VISIBILITY [ICAO]- The ability, as determined by
atmospheric conditions and expressed in units of
distance, to see and identify prominent unlighted
objects by day and prominent lighted objects by
night.
a. Flight Visibility- The visibility forward from
the cockpit of an aircraft in flight.
b. Ground Visibility- The visibility at an
aerodrome as reported by an accredited observer.
c. Runway Visual Range [RVR]- The range over
which the pilot of an aircraft on the centerline of a
runway can see the runway surface markings or the
lights delineating the runway or identifying its
centerline.