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Pilot/Controller Glossary 

12/2/21 

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 responsibil-
ity 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, bound-
aries, 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 horizon-

tal 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 visi-

bility 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 instrumen-

tally 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. 

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

PCG V