Terminal control area
TMZ Transponder Mandatory Zone
TODA Take-off distance available
TOP Cloud top
TORA Take-off run available
TP Turning point
TR Track
TRA Temporary reserved airspace
TRANS Transmits or transmitter
TS Thunderstorm
TSGR Thunderstorm with hail
TSSA Thunderstorm with duststorm or sandstorm
TT Teletypewriter
Tue Tuesday
TURB Turbulence
TVOR Terminal VOR
TWP Turning waypoint
TWR Aerodrome control tower or aerodrome control
TWY Taxiway
TXT Text
TYP Type of aircraft
U
UAC Upper area control centre
UDF UHF direction finding station
UFN Until further notice
UHF Ultra high frequency (300 to 3000 MHz)
UIC Upper information centre
UIR Upper information region
UNL Unlimited
UNREL Unreliable
U/S Unserviceable
USAFE US Air Force – Europe
USAEUR US Army – Europe
UTA Upper control area
UTC Co-ordinated Universal Time
V
VA Volcanic Ash
VAL Visual approach and landing chart
VAR Magnetic variation
VASIS Visual approach slope indicator system
VDF VHF direction finding station
VFR Visual flight rules
VHF Very high frequency (30 MHz to 300 MHz)
VIA By way of …
VIO Severe (used to qualify interference or static reports)
VIP Very important person
VIS Visibility
VLR Very long range
VMC Visual meteorological condition
VOLMET Meteorological information for aircraft in flight
VOR VHF Omnidirectional radio range
VORTAC VOR and TACAN combination
VOT VOR airborne equipment test facility
VRB Variable
Vs Stalling speed
VTOL Vertical take-off and landing
W
W West or western longitute
W White
WAFC World Area Forecast Centre
WAFS World Area Forecast System
WDI Wind direction indicator
Wed Wednesday
WEF With effect from or effective from
WGS World Geodetic System
WIE With immediate effect or effective immediately
WIP Work in progress
WNW West-northwest
WS Wind Sheer
WSPD Wind speed
WSW West-southwest
W/T Wind/temperature
WX Weather
X
XBAR Crossbar (of approach lighting system)
XS Atmospheric
Y
Y Yellow
YCZ Yellow caution zone (runway lighting)
yd Yard(s)
YR Your
Measurements
Air Pressure
Hektopascal (hPa)
Sometimes we also find inch in older instruments
Altitudes
Will be expressed and transmitted in feet
Breaking action
Friction coefficient
This is a part of the permanent snow plan applicable for the international airports. The mean friction coefficient will be indicated for each third for the runway. The breaking action will be measured continuously by the Skiddometer, the Surface-Friction-Tester or Tapley-Meter. All friction coefficients are measured and will be given on the basis of the following
| 0,40 and above | good | Code 5 |
| 0,39 – 0,36 | medium to good | Code 4 |
| 0,35 – 0,30 |
|
