Aeronautical Terms beginning with S
SA
Selective Availability.
SAAAR
Special Aircraft and Aircrew Authorization Required
SALS
Short Approach Light System.
SAS
Stability Augmentation System
Satellite ephemeris data
Data broadcast by the GPS satellite containing very accurate orbital data for that satellite, atmospheric propagation data, and satellite clock error data.
Scan
The first fundamental skill of instrument flight, also known as cross-check; the continuous and logical observation of instruments for attitude and performance information.
SDF
Simplified Directional Facility.
Selective availability (SA)
A satellite technology permitting the Department of Defense (DOD) to create, in the interest of national security, a significant clock and ephemeris error in the satellites, resulting in a navigation error.
Semicircular canal
An inner ear organ that detects angular acceleration of the body.
Sensitive altimeter
A form of multipointer pneumatic altimeter with an adjustable barometric scale that allows the reference pressure to be set to any desired level.
Separation
In air traffic control, the spacing of aircraft to achieve their safe and orderly movement in flight and while landing and taking off.
Separation Minima
The minimum longitudinal, lateral, or vertical distances by which aircraft are spaced through the application of air traffic control procedures.
SER
Start End of Runway
Short Range Clearance
A clearance issued to a departing IFR flight which authorizes IFR flight to a specific fix short of the destination while air traffic control facilities are coordinating and obtaining the complete clearance.
SIAP
Standard Instrument Approach Procedure
SID
Standard Instrument Departure
Sidestep Maneuver
A visual maneuver accomplished by a pilot at the completion of an instrument approach to permit a straight-in landing on a parallel runway not more than 1,200 feet to either side of the runway to which the instrument approach was conducted.
SIDS
Standard Instrument Departure Procedures.
SIGMET
The acronym for Significant Meteorological information. A weather advisory issued concerning weather significant to the safety of all aircraft.
Signal-to-noise ratio
An indication of signal strength received compared to background noise, which is a measure of how adequate the received signal is.
Significant Point
A point, whether a named intersection, a NAVAID, a fix derived from a NAVAID(s), or geographical coordinate expressed in degrees of latitude and longitude, which is established for the purpose of providing separation, as a reporting point, or to delineate a route of flight.
Simplex
Transmission and reception on the same frequency.
Simplified directional facility (SDF)
A NAVAID used for nonprecision instrument approaches. The final approach course is similar to that of an ILS localizer; however, the SDF course may be offset from the runway, generally not more than 3°, and the course may be wider than the localizer, resulting in a lower degree of accuracy.
Simultaneous ILS Approaches
An approach system permitting simultaneous ILS/MLS approaches to airports having parallel runways separated by at least 4,300 feet between centerlines. Integral parts of a total system are ILS/MLS, radar, communications, ATC procedures, and appropriate airborne equipment.
Simultaneous MLS Approaches
An approach system permitting simultaneous ILS/MLS approaches to airports having parallel runways separated by at least 4,300 feet between centerlines. Integral parts of a total system are ILS/MLS, radar, communications, ATC procedures, and appropriate airborne equipment.
Single Direction Routes
Preferred IFR Routes which are sometimes depicted on high altitude en route charts and which are normally flown in one direction only.
Single-pilot resource management (SRM)
The ability for crew or pilot to manage all resources effectively to ensure the outcome of the flight is successful.
Situational awareness
Pilot knowledge of where the aircraft is in regard to location, air traffic control, weather, regulations, aircraft status, and other factors that may affect flight.
Skidding turn
An uncoordinated turn in which the rate of turn is too great for the angle of bank, pulling the aircraft to the outside of the turn.
Slant range
The horizontal distance from the aircraft antenna to the ground station, due to line-of-sight transmission of the DME signal.
Slaved compass
A system whereby the heading gyro is slaved to, or continuously corrected to bring its direction readings into agreement with a remotely located magnetic direction sensing device (usually this is a flux valve or flux gate compass).
Slipping turn
An uncoordinated turn in which the aircraft is banked too much for the rate of turn, so the horizontal lift component is greater than the centrifugal force, pulling the aircraft toward the inside of the turn.
SM
Statute Mile
SMA
Surface Movement Advisor
SOIA
Simultaneous Offset Instrument Approaches
Somatogravic illusion
The misperception of being in a nose-up or nose-down attitude, caused by a rapid acceleration or deceleration while in flight situations that lack visual reference.
SOP
Standard Operating Procedure
Spatial disorientation
The state of confusion due to misleading information being sent to the brain from various sensory organs, resulting in a lack of awareness of the aircraft position in relation to a specific reference point.
Special Instrument Approach Procedure
A procedure approved by the FAA for individual operators, but not published in FAR 97 for public use.
Special use airspace
Airspace in which flight activities are subject to restrictions that can create limitations on the mixed use of airspace. Consists of prohibited, restricted, warning, military operations, and alert areas.
SRM
Single-pilot Resource Management.
SSALF
Simplified Short Approach Light System With Sequenced Flashing Lights
SSALR
Simplified Short Approach Light System With Runway Alignment Indicator Lights
SSALS
Simplified Short Approach Light System.
SSALSR
Simplified Short Approach Light System with Runway Alignment Indicator Lights.
SSR
Secondary Surveillance Radar.
SSV
Standard Service Volume.
St. Elmo’s Fire
A corona discharge which lights up the aircraft surface areas where maximum static discharge occurs.
Standard atmosphere
At sea level, the standard atmosphere consists of a barometric pressure of 29.92 inches of mercury ("Hg) or 1013.2 millibars, and a temperature of 15°C (59°F). Pressure and temperature normally decrease as altitude increases. The standard lapse rate in the lower atmosphere for each 1,000 feet of altitude is approximately 1"Hg and 2°C (3.5°F). For example, the standard pressure and temperature at 3,000 feet mean sea level (MSL) are 26.92"Hg (29.92"Hg – 3"Hg) and 9°C (15°C – 6°C).
Standard holding pattern
A holding pattern in which all turns are made to the right.
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.
Standard instrument departure procedures (SIDS).
Published procedures to expedite clearance delivery and to facilitate transition between takeoff and en route operations.
Standard rate turn
A turn in which an aircraft changes its direction at a rate of 3° per second (360° in 2 minutes) for low- or medium-speed aircraft. For high-speed aircraft, the standard rate turn is 1 1⁄2° per second (360° in 4 minutes).
Standard Service Volume
Most air navigation radio aids which provide positive course guidance have a designated standard service volume (SSV). The SSV defines the reception limits of unrestricted NAVAIDS which are usable for random/unpublished route navigation. Standard service volume limitations do not apply to published IFR routes or procedures. See the AIM for the SSV for specific NAVAID types.
Standard Terminal Arrival (STAR)
Provides a common method for departing the en route structure and navigating to your destination. A STAR is a preplanned instrument flight rule ATC arrival procedure published for pilot use in graphic and textual form to simplify clearance delivery procedures. STARs provide you with a transition from the en route structure to an outer fix or an instrument approach fix or arrival waypoint in the terminal area, and they usually terminate with an instrument or visual approach procedure.
STAR
Standard Terminal Arrival Route.
STAR Transition
A published segment used to connect one or more en route airways, jet routes, or RNAV routes to the basic STAR procedure. It is one of several routes that bring traffic from different directions into one STAR. NACO publishes STARs for airports with procedures authorized by the FAA, and these STARs are included at the front of each Terminal Procedures Publication regional booklet.
STARS
Standard Terminal Automation Replacement System
Start End of Runway (SER)
The beginning of the takeoff runway available.
Static longitudinal stability
The aerodynamic pitching moments required to return the aircraft to the equilibrium angle of attack.
Static pressure
Pressure of air that is still, or not moving, measured perpendicular to the surface of the aircraft.
Station Declination
The angular difference between true north and the zero radial of a VOR at the time the VOR was last site checked.
Steep turns
In instrument flight, any turn greater than standard rate; in visual flight, anything greater than a 45° bank.
Stepdown Fix
A fix permitting additional descent within a segment of an instrument approach procedure by identifying a point at which a controlling obstacle has been safely overflown.
STMP
Special Traffic Management Program
Straight-In Approach IFR
An instrument approach wherein final approach is begun without first having executed a procedure turn, not necessarily completed with a straight-in landing or made to straight-in landing minimums.
Straight-In Area
A type of Terminal Arrival Area. A 30NM arc centered on the IF (Intermediate Fix) bounded by a straight line extending through the IF perpendicular to the intermediate course.
Straight-In Landing
A landing made on a runway aligned within 30° of the final approach course following completion of an instrument approach.
Straight-In Minimums
Straight-In Landing Minimums.
Structural icing
The accumulation of ice on the exterior of the aircraft.
SUA/ISE
Special Use Airspace/Inflight Service Enhancement
Suction relief valve
A relief valve in an instrument vacuum system required to maintain the correct low pressure inside the instrument case for the proper operation of the gyros.
Suitable RNAV system
An RNAV system that meets the required performance established for a type of operation, e.g. IFR; and is suitable for operation over the route to be flown in terms of any performance criteria (including accuracy) established by the air navigation service provider for certain routes (e.g. oceanic, ATS routes, and IAPs). An RNAV system’s suitability is dependent upon the availability of ground and/or satellite navigation aids that are needed to meet any route performance criteria that may be prescribed in route specifications to navigate the aircraft along the route to be flown. Information on suitable RNAV systems is published in FAA guidance material.
Surface Incident
An event during which authorized or unauthorized/unapproved movement occurs in the movement area or an occurrence in the movement area associated with the operation of an aircraft that affects or could affect the safety of flight.
Surface Movement Guidance Control System (SMGCS)
Facilitates the safe movement of aircraft and vehicles at airports where scheduled air carriers are conducting authorized operations. The SMGCS low visibility taxi plan includes the improvement of taxiway and runway signs, markings, and lighting, as well as the creation of SMGCS low visibility taxi route charts.
Surveillance Approach
An instrument approach wherein the air traffic controller issues instructions, for pilot compliance, based on aircraft position in relation to the final approach course (azimuth), and the distance (range) from the end of the runway as displayed on the controller’s radar scope. The controller will provide recommended altitudes on final approach if requested by the pilot.
SWAP
Severe Weather Avoidance Plan
Synthetic Vision
A visual display of terrain, obstructions, runways, and other surface features that creates a virtual view of what the pilot would see out the window. This tool could be used to supplement normal vision in low visibility conditions, as well as to increase situational awareness in IMC.
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