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Pilot/Controller Glossary

WIDE AREA MULTILATERATION (WAM)- A distributed surveillance technology
which may utilize any

combination of signals from Air Traffic Control Radar Beacon System
(ATCRBS) (Modes A and C) and Mode

S transponders, and ADS-B transmissions.  Multiple geographically
dispersed ground sensors measure the

time-of-arrival of the transponder messages. Aircraft position is
determined by joint processing of the

time-difference-of-arrival (TDOA) measurements computed between a
reference and the ground stations'

measured time-of-arrival.

WILCO

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I have received your message, understand it, and will comply with it.

WIND GRID DISPLAY

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 A display that presents the latest forecasted wind data overlaid on a
map of the ARTCC

area. Wind data is automatically entered and updated periodically by
transmissions from the National Weather

Service. Winds at specific altitudes, along with temperatures and air
pressure can be viewed.
WIND SHEAR

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 A change in wind speed and/or wind direction in
a short distance resulting in a tearing or

shearing effect. It can exist in a horizontal or vertical direction and
occasionally in both.
WIND SHEAR ESCAPE

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 An unplanned abortive maneuver initiated by the pilot in command (PIC)
as a result

of onboard cockpit systems. Wind shear escapes are characterized by
maximum thrust climbs in the low altitude

terminal environment until wind shear conditions are no longer
detected.
WING TIP VORTICES

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(See VORTICES.)

WORDS TWICE

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a.

As a request: "Communication is
difficult. Please say every phrase twice."

b.

As information: "Since communications are difficult, every phrase in
this message will be spoken twice."

WS

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(See SIGMET.)
(See WEATHER ADVISORY.)

WST

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(See CONVECTIVE SIGMET.)
(See WEATHER ADVISORY.)

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