Pilot/Controller Glossary 

4/20/23 

VISUAL HOLDING

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 The holding of aircraft at selected, prominent geographical fixes which can be easily 

recognized from the air. 

(See HOLDING FIX.) 

VISUAL LINE OF SIGHT (VLOS)

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 Condition of operations wherein the operator maintains continuous, 

unaided visual contact with the unmanned aircraft. 
VISUAL METEOROLOGICAL CONDITIONS

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 Meteorological conditions expressed in terms of visibility, 

distance from cloud, and ceiling equal to or better than specified minima. 

(See INSTRUMENT FLIGHT RULES.) 
(See INSTRUMENT METEOROLOGICAL CONDITIONS.) 
(See VISUAL FLIGHT RULES.) 

VISUAL OBSERVER (VO)

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 A person who is designated by the remote pilot in command to assist the remote 

pilot in command and the person operating the flight controls of the small UAS (sUAS) to see and avoid other 

air traffic or objects aloft or on the ground. 
VISUAL SEGMENT

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(See PUBLISHED INSTRUMENT APPROACH PROCEDURE VISUAL SEGMENT.) 

VISUAL SEPARATION

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 A means employed by ATC to separate aircraft in terminal areas and en route airspace 

in the NAS. There are two ways to effect this separation: 

a. 

The tower controller sees the aircraft involved and issues instructions, as necessary, to ensure that the 

aircraft avoid each other. 

b. 

A pilot sees the other aircraft involved and upon instructions from the controller provides his/her own 

separation by maneuvering his/her aircraft as necessary to avoid it. This may involve following another aircraft 

or keeping it in sight until it is no longer a factor. 

(See SEE AND AVOID.) 
(Refer to 14 CFR Part 91.) 

VLF

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(See VERY LOW FREQUENCY.) 

VMC

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(See VISUAL METEOROLOGICAL CONDITIONS.) 

VOICE SWITCHING AND CONTROL SYSTEM (VSCS)

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 A computer controlled switching system that 

provides air traffic controllers with all voice circuits (air to ground and ground to ground) necessary for air traffic 

control. 

(Refer to AIM.) 

VOR

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 A ground-based electronic navigation aid transmitting very high frequency navigation signals, 360 

degrees in azimuth, oriented from magnetic north. Used as the basis for navigation in the National Airspace 

System. The VOR periodically identifies itself by Morse Code and may have an additional voice identification 

feature. Voice features may be used by ATC or FSS for transmitting instructions/information to pilots. 

(See NAVIGATIONAL AID.) 
(Refer to AIM.) 

VOR TEST SIGNAL

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(See VOT.) 

VORTAC

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 A navigation aid providing VOR azimuth, TACAN azimuth, and TACAN distance measuring 

equipment (DME) at one site. 

(See DISTANCE MEASURING EQUIPMENT.) 
(See NAVIGATIONAL AID.) 
(See TACAN.) 
(See VOR.) 
(Refer to AIM.) 

PCG V

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