VR Rotation Speed
VS Stalling Speed or the
Minimum Steady Flight
Speed at which the Airplane
is Controllable
VS0 Stalling Speed or the
Minimum Steady Flight
Speed in the Landing
Configuration
VS1 Stalling Speed or the
Minimum Steady Flight
Speed Obtained in a Specific
Configuration
V1 Take-off Decision Speed
(formerly Denoted as Critical
Engine Failure Speed)
V2 Take-off Safety Speed
V2 MIN Minimum Take-off Safety
Speed
V/L VOR/Localizer
V/S, VS Vertical Speed
VERT Vertical
VF Variable Frequency
VFG Variable Frequency
Generator
VFR Visual Flight Rules
VG Vertical Gyro
VHF Very High Frequency
(30 − 300 MHz)
VIB Vibration
VIGB Variable Inlet Guide Vanes
VMC Visual Meteorological
Conditions
VNAV Vertical Navigation
VOL Volume
VOLT Voltage
VOR VHF Omnidirectional Range
Station
VORTAC VOR and TACAN Co-located
VSI Vertical Speed Indicator
W
W Warning
W/C Wind Component
W/S Wind Shear
W/W Wheel Well
WAI Wing Anti-Ice
WAIV Wing Anti-Ice modulating and
Shut-off Valve
WARN Warning
WF Runway Length Limited
Weight
Wf Fuel Flow In Pounds Per
Hour
WGT Weight
WHLS Wheels
WIND Window
WOW Weight-On-Wheel
WPT(s) Waypoint(s)
WRN Warning
WS Second Segment Limited
Weight
WTC Windshield Temperature
Control
WSHLD Windshield
WX Weather
WXR Weather Radar
X
X Cross Transfer
XFEED Crossfeed
XFER, XFR Transfer
XFLOW Cross Flow
XMIT Transmit
XPNDR Transponder
XTK Cross Track
XWC Cross Wind Component

Y
Y/D, YD Yaw Damper
Z
ZFW Zero Fuel Weight