WA -- WST
WA-
WAKE TURBULENCE- Phenomena resulting from
the passage of an aircraft through the atmosphere. The term includes vortices,
thrust stream turbulence, jet blast, jet wash, propeller wash, and rotor wash
both on the ground and in the air.
WARNING AREA- (See SPECIAL USE AIRSPACE.)
WAYPOINT- A predetermined geographical position used for route/instrument
approach definition, or progress reporting purposes, that is defined relative to
a VORTAC station or in terms of latitude/longitude coordinates.
WEATHER ADVISORY- In aviation weather forecast practice, an expression of
hazardous weather conditions not predicted in the area forecast, as they affect
the operation of air traffic and as prepared by the NWS.
WHEN ABLE- When used in conjunction
with ATC instructions, gives the pilot the latitude to delay compliance until a
condition or event has been reconciled. Unlike "pilot discretion," when
instructions are prefaced "when able," the pilot is expected to seek the first
opportunity to comply. Once a maneuver has been initiated, the pilot is expected
to continue until the specifications of the instructions have been met. "When
able," should not be used when expeditious compliance is required.
WILCO- I have received your message, understand it, and will
comply with it.
WIND SHEAR- 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.
WING TIP VORTICES-
WORDS TWICE-
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."
WORLD AERONAUTICAL CHARTS-
(See AERONAUTICAL CHART.)
WS-
WST-