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Flashcards in S Deck (43):

St. Elmo's Fire

A corona discharge which lights up the aircraft
surface areas where maximum static discharge occurs.


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.


Sea breeze

A coastal breeze blowing from sea to land
caused by the temperature difference when the land surface is
warmer than the sea surface. The sea breeze usually occurs
during the day and alternates with the land breeze that blows
in the opposite direction at night.


Sea level engine

A reciprocating aircraft engine having a
rated takeoff power that is producible only at sea level.



The first fundamental skill of instrument flight, also
known as “cross-check;” the continuous and logical observation
of instruments for attitude and performance information.


Sectional aeronautical charts

Designed for visual
navigation of slow- or medium-speed aircraft. Topographic
information on these charts features the portrayal of relief,
and a judicious selection of visual check points for VFR
flight. Aeronautical information includes visual and radio
aids to navigation, airports, controlled airspace, restricted
areas, obstructions and related data.


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.



A fuselage design that includes a
substructure of bulkheads and/or formers, along with
stringers, to support flight loads and stresses imposed on
the fuselage.


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.


Service ceiling

The maximum density altitude where the best
rate-of-climb airspeed will produce a 100-feet-per-minute
climb at maximum weight while in a clean configuration
with maximum continuous power.



A motor or other form of actuator which receives a
small signal from the control device and exerts a large force
to accomplish the desired work.


Servo tab

An auxiliary control mounted on a primary control
surface, which automatically moves in the direction opposite
the primary control to provide an aerodynamic assist in the
movement of the control.



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 the adequacy of the received signal.


Significant weather prognostic

Presents four panels showing forecast significant weather.



Transmission and reception on the same frequency.


Simplified directional facility (SDF)

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.


Single-pilot resource management (SRM)

The ability
for a 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.


Skills and procedures

The procedural, psychomotor, and
perceptual skills used to control a specific aircraft or its
systems. They are the airmanship abilities that are gained
through conventional training, are perfected, and become
almost automatic through experience.


Skin friction drag

Drag generated between air molecules and the solid surface of the aircraft


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 a flux valve or flux gate


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.


Small airplane

An airplane of 12,500 pounds or less maximum certificated takeoff weight.


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.


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 flight permit

A flight permit issued to an aircraft
that does not meet airworthiness requirements but is capable
of safe flight. A special flight permit can be issued to move
an aircraft for the purposes of maintenance or repair, buyer
delivery, manufacturer flight tests, evacuation from danger,
or customer demonstration. Also referred to as a ferry


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.


Special fuel consumption

. The amount of fuel in pounds
per hour consumed or required by an engine per brake
horsepower or per pound of thrust.



The distance traveled in a given time.



An aggravated stall that results in an airplane descending in a helical, or corkscrew path.


Spiral instability

A condition that exists when the
static directional stability of the airplane is very strong as
compared to the effect of its dihedral in maintaining lateral


Spiraling slipstream

The slipstream of a propeller-driven
airplane rotates around the airplane. This slipstream strikes
the left side of the vertical fin, causing the aircraft to yaw
slightly. Rudder offset is sometimes used by aircraft designers
to counteract this tendency.



High-drag devices that can be raised into the air
flowing over an airfoil, reducing lift and increasing drag.
Spoilers are used for roll control on some aircraft. Deploying
spoilers on both wings at the same time allows the aircraft
to descend without gainingspeed. Spoilers are also used to
shorten the ground roll after landing.



A single-piece horizontal tail surface on an
airplane that pivots around a central hinge point. A stabilator
serves the purposes of both the horizontal stabilizer and the



. The inherent quality of an airplane to correct for
conditions that may disturb its equilibrium, and to return or to
continue on the original flightpath. It is primarily an airplane
design characteristic.


Stagnant hypoxia

A type of hypoxia that results when the
oxygen-rich blood in the lungs is not moving to the tissues
that need it.



A rapid decrease in lift caused by the separation of
airflow from the wing’s surface, brought on by exceeding
the critical angle of attack. A stall can occur at any pitch
attitude or airspeed.


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 empty weight (GAMA)

This weight consists of
the airframe, engines, and all items of operating equipment
that have fixed locations and are permanently installed in the
airplane including fixed ballast, hydraulic fluid, unusable
fuel, and full engine oil.