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Pilot/Controller Glossary

3/29/18

PCG V−4

VISUAL SEPARATION− 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−

(See VERY LOW FREQUENCY.)

VMC−

(See VISUAL METEOROLOGICAL

CONDITIONS.)

VOICE SWITCHING AND CONTROL SYSTEM

(VSCS)− 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− 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/in-

formation to pilots.

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

VOR TEST SIGNAL−

(See VOT.)

VORTAC− 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.)

VORTICES− Circular patterns of air created by the

movement of an airfoil through the air when

generating lift. As an airfoil moves through the

atmosphere in sustained flight, an area of area of low

pressure is created above it. The air flowing from the

high pressure area to the low pressure area around and

about the tips of the airfoil tends to roll up into two

rapidly rotating vortices, cylindrical in shape. These

vortices are the most predominant parts of aircraft

wake turbulence and their rotational force is

dependent upon the wing loading, gross weight, and

speed of the generating aircraft. The vortices from

medium to super aircraft can be of extremely high

velocity and hazardous to smaller aircraft.

(See AIRCRAFT CLASSES.)
(See WAKE TURBULENCE.)
(Refer to AIM.)

VOT− A ground facility which emits a test signal to

check VOR receiver accuracy. Some VOTs are

available to the user while airborne, and others are

limited to ground use only.

(See CHART SUPPLEMENT U.S.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)

VR−

(See VFR MILITARY TRAINING ROUTES.)

VSCS−

(See VOICE SWITCHING AND CONTROL

SYSTEM.)

VTA−

(See VERTEX TIME OF ARRIVAL.)

VTOL AIRCRAFT−

(See VERTICAL TAKEOFF AND LANDING

AIRCRAFT.)