PCG WA -- WST
WA -- WST
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-
a. As a request: "Communication is difficult. Please say every
b. As information: "Since communications are difficult, every
phrase in this message will be spoken twice."
WORLD AERONAUTICAL CHARTS-
(See AERONAUTICAL CHART.)