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12/2/21 

Pilot/Controller Glossary 

potential danger. A warning area may be located over 
domestic or international waters or both. 

SPECIAL VFR CONDITIONS

 Meteorological 

conditions that are less than those required for basic 
VFR flight in Class B, C, D, or E surface areas and 
in which some aircraft are permitted flight under 
visual flight rules. 

(See SPECIAL VFR OPERATIONS.) 
(Refer to 14 CFR Part 91.) 

SPECIAL VFR FLIGHT [ICAO]

 A VFR flight 

cleared by air traffic control to operate within Class 
B, C, D, and E surface areas in meteorological 
conditions below VMC. 

SPECIAL VFR OPERATIONS

 Aircraft operating 

in accordance with clearances within Class B, C, D, 
and E surface areas in weather conditions less than the 
basic VFR weather minima. Such operations must be 
requested by the pilot and approved by ATC. 

(See SPECIAL VFR CONDITIONS.) 
(See ICAO term SPECIAL VFR FLIGHT.) 

SPEED

 

(See AIRSPEED.) 
(See GROUND SPEED.) 

SPEED ADJUSTMENT

 An ATC procedure used to 

request pilots to adjust aircraft speed to a specific 
value for the purpose of providing desired spacing. 
Pilots are expected to maintain a speed of plus or 
minus 10 knots or 0.02 Mach number of the specified 
speed. Examples of speed adjustments are: 

a. 

“Increase/reduce speed to Mach point 

(number).” 

b. 

“Increase/reduce speed to (speed in knots)” or 

“Increase/reduce speed (number of knots) knots.” 

SPEED BRAKES

 Moveable aerodynamic devices 

on aircraft that reduce airspeed during descent and 
landing. 

SPEED SEGMENTS

 Portions of the arrival route 

between the transition point and the vertex along the 
optimum flight path for which speeds and altitudes 
are specified. There is one set of arrival speed 
segments adapted from each transition point to each 
vertex. Each set may contain up to six segments. 

SPOOFING

 Denotes emissions of GNSS

like 

signals that may be acquired and tracked in 
combination with or instead of the intended signals 

by civil receivers. The onset of spoofing effects can 
be instantaneous or delayed, and effects can persist 
after the spoofing has ended.  Spoofing can result in 
false and potentially confusing, or hazardously 
misleading, position, navigation, and/or date/time 
information in addition to loss of GNSS use. 

SPEED ADVISORY

 Speed advisories that are 

generated within Time

Based Flow Management to 

assist controllers to meet the Scheduled Time of 
Arrival (STA) at the meter fix/meter arc. See also 
Ground

Based Interval Management

Spacing 

(GIM

S) Speed Advisory. 

SQUAWK (Mode, Code, Function)

 Used by ATC 

to instruct a pilot to activate the aircraft transponder 
and ADS

B Out with altitude reporting enabled, or 

(military) to activate only specific modes, codes, or 
functions. Examples: “Squawk five seven zero 
seven;” “Squawk three/alpha, two one zero five.” 

(See TRANSPONDER.) 

STA

 

(See SCHEDULED TIME OF ARRIVAL.) 

STAGING/QUEUING

 The placement, integration, 

and segregation of departure aircraft in designated 
movement areas of an airport by departure fix, EDCT, 
and/or restriction. 

STAND BY

 Means the controller or pilot must 

pause for a few seconds, usually to attend to other 
duties of a higher priority. Also means to wait as in 
“stand by for clearance.” The caller should 
reestablish contact if a delay is lengthy. “Stand by” is 
not an approval or denial. 

STANDARD INSTRUMENT APPROACH PRO­
CEDURE (SIAP)

 

(See INSTRUMENT APPROACH PROCEDURE.) 

STANDARD INSTRUMENT DEPARTURE (SID)

 

A preplanned instrument flight rule (IFR) air traffic 
control (ATC) departure procedure printed for 
pilot/controller use in graphic form to provide 
obstacle clearance and a transition from the terminal 
area to the appropriate en route structure. SIDs are 
primarily designed for system enhancement to 
expedite traffic flow and to reduce pilot/controller 
workload. ATC clearance must always be received 
prior to flying a SID. 

(See IFR TAKEOFF MINIMUMS AND 

DEPARTURE PROCEDURES.) 

(See OBSTACLE DEPARTURE PROCEDURE.) 
(Refer to AIM.) 

PCG S