WFA  WXR Flat Plate Antenna 
WGS  World Geodetic System 
WGS-72  World Geodetic Survey of 1972 
WGS-84  World Geodetic System 1984 
Whisper- A sequence of ATCRBS interrogations and suppres 
Shout  sions of varying power levels transmitted by TCAS 
equipment to reduce severity of synchronous interfer 
ence and multipath problems. 
WIP  Work In Progress 
WMA  WXR Antenna Pedestal & WXR Waveguide Adapter 
WMI  WXR Indicator Mount 
WMS  Wide-area Master Station 
WMT  WXR Mount 
WN  Week Number 
WORD  Grouping of bits. Size of group varies from micro-
processor to microprocessor. 
WOW  Weight On Wheels 
WP  Working Paper 
WPT  Waypoint 
WRC  World Radiocommunication Conference 
WRS  Wide-area Reference Station 
WRT  WXR Receiver/Transmitter 
WWW  Internet World Wide Web 
WX  Weather 
WXI  WXR Indicator 
WXP  Weather Radar Panel 
WXR  Weather Radar System 
WYPT  Waypoint Altitude 

X

X - BA N D C h a n n e l
X.25 XCVR XFR XLTR XM XMIT XMTR XPD XPDR
Yagi Antenna
YSAS YD
Z ZFW Z-Marker
The frequency ra n ge between 8000 and 12500 MHzX- A DME ch a n n e l . T h e re are 126 X-Channels for DME opera t i o n . For the fi rst 63 ch a n n e l s , the gro u n d -to-air frequency is 63 MHz below the air-to-ground f re q u e n c y. For the second 63 X-channels the gro u n d -to-air frequency is 63 MHz ab ove the air-to-ground f re q u e n c y.
Packet Switched Data Network Transceiver Transfer Translator External Master Transmit Transmitter ATC Transponder (also XPDR,XPNDR,TPR)
Transponder
Y
An antenna with its maximum radiation parallel to the long axis of its array, consisting of a driven dipole, a parasitic dipole reflector, and one parasitic dipole director or more.
Yaw Stability Augmentation System
Yaw Damper
Z
Refer to reflectivity factor Zero Fuel Weight
A marker beacon,sometimes referred to as a station locator, that provides positive identification to the pilot when the aircraft is passing directly over a low-frequency navigation aid.