- S -

SAILPLANE - An unpowered, soaring aircraft capable of maintaining level flight for long periods of time after release from tow and of gaining altitude using wind currents, as opposed to a glider.

SCHEDULED SERVICE - Transport service operated pursuant to published flight schedules, including extra sections and related non revenue flights.

SCUD - A low, foglike cloud layer of obscuring phenomenon.

SEAPLANE - A water-based aircraft with a boat-hull fuselage.

SECONDARY STALL - Any stall resulting from pulling back too soon and too hard while recovering from any other stall.

SERVICE CEILING - The height above sea level at which an aircraft with normal rated load is unable to climb faster than 100 feet per minute under Standard air conditions.

SIDESLIP - A movement of an aircraft in which a relative flow of air moves along the lateral axis, resulting in a sideways movement from a projected flight path.

SINCE MAJOR OVERHAUL (SMOH) - an acronym seen in reference to the operating hours, or time remaining, on an engine.

SINK RATE - The speed at which an aircraft loses altitude, especially in a glide in still air under given conditions of equilibrium.

SITUATIONAL AWARENESS - Situational awareness provides the pilots with information relative to the current surroundings, such as other aircraft or threats in the immediate area.

SKID - Too shallow a bank in a turn, causing an aircraft to slide outward from its ideal turning path.

SLATS - Movable vanes or auxiliary airfoils, usually set along the leading edge of a wing but able to be lifted away at certain angles of attack.

SLIP - Too steep a bank in a turn, causing an aircraft to turn inward from its ideal turning path.

SLIPSTREAM - The flow of air driven backward by a propeller or downward by a rotor.

SLOP - Slop occurs when a control surfaces movement does not move the servo. Common cause is a worn linkage point or poor linkage setup.

SLOT - A long, narrow, spanwise gap in a wing, usually near the leading edge, to improve airflow at high angles of attack allowing for slowing landing speeds.

SLOTTED FLAP - A flap that, when depressed, exposes a slot and increases airflow between itself and the rear edge of the wing.

SMALL AIRCRAFT - aircraft of 12,500 pounds or less, maximum certificated takeoff weight.

SPECIAL USE AIRSPACE - Airspace of defined dimensions identified by an area on the surface of the earth wherein activities must be confined because of their nature and/or wherein limitations may be imposed upon aircraft operations that are not a part of those activities. Types of special use airspace are: Alert Area - Airspace which may contain a high volume of pilot training activities or an unusual type of aerial activity, neither of which is hazardous to aircraft. Alert Areas are depicted on aeronautical charts for the information of nonparticipating pilots. All activities within an Alert Area are conducted in accordance with Federal Aviation Regulations, and pilots of participating aircraft as well as pilots transiting the area are equally responsible for collision avoidance; Controlled Firing Area - Airspace wherein activities are conducted under conditions so controlled as to eliminate hazards to nonparticipating aircraft and to ensure the safety of persons and property on the ground; Military Operations Area (MOA).

SPECIAL VFR CONDITIONS - meteorological conditions that are less than those required for basic VFR flight in controlled airspace and in which some aircraft are permitted fight under visual flight rules.

SPECIAL VFR OPERATIONS - aircraft operating in accordance with clearances within controlled airspace in meteorological conditions less than the basic VFR weather minima. Such operations must be requested by the pilot and approved by ATC.

SPEED BRAKES - Large panels that fold out of the aircraft structure to provide a lot of extra drag to the air. They are not part of the wing structure, but are usually mounted on the fuselage. Military jets most often have speed brakes, which fold out of the fuselage. Some airliners use spoilers as speed brakes when at altitude.

SPIN - A maneuver where one wing is stalled and the other is still flying. This causes the airplane to rotate around its middle while it descends at a high rate of speed. When it`s done on purpose, it is a precision maneuver, with the pilot trying to get the airplane to rotate an exact number of turns from entry to exit.

SPLIT FLAP - A flap built into the underside of a wing, as opposed to a full flap wherein a whole portion of the trailing edge is used.

SPOILER - A long, movable, narrow plate along the upper surface of an airplane wing used to reduce lift and increase drag by breaking or spoiling the laminar airflow over the surface of the wing.

SQUAWK - A four-digit number which is dialed into his/her transponder by a pilot to identify his/her aircraft to air traffic controllers.

SSALS - simplified short approach light system.

SSALSR - simplified short approach light system with runway alignment indicator lights.

STABILATOR - A movable horizontal tail that combines the actions of a stabilizer and elevator, increasing longitudinal stability while creating a pitching moment.

STABILIZER - The fixed part of a horizontal airfoil that controls the pitch of an aircraft with the movable part being the elevator.

STALL - 1) A sudden loss of lift caused by the angle of attack increasing to a point where the flow of air breaks away from a wing or airfoil. 2) A maneuver initiated by a steep raising of the aircraft's nose resulting in an abrupt drop.

STANDARD AIR ( STANDARD ATMOSPHERE) - An arbitrary atmosphere established for calibration of aircraft instruments. Standard Air Density is 29.92 inches of mercury and at a temperature of 59º F, equivalent to an atmospheric air pressure of 14.5 lbs. per square inch.

STANDARD RATE TURN - A turn at which the heading of an aircraft chances 3º per second or 360º in two minutes.

STATIC WIRE - A clip-on wire used to ground an aircraft by drawing off static electricity, a potential fire hazard, during refueling.

STOL - Short takeoff and landing ability.

STOP WAY - an area beyond the takeoff runway, no less wide than the runway and centered upon the extended centerline of the runway, able to support the airplane during an aborted takeoff, without causing structural damage to the airplane, and designated by the airport authorities for use in decelerating the airplane during an aborted takeoff.

STRUT - Basically this is a supporting member. A wing strut supports the wing, and goes from the fuselage to the wing. Cabane struts are on biplanes, and support the upper wing over the fuselage. A landing gear strut is the portion that holds the wheel assembly to the airplane, and away from the wing or fuselage.

SUMPS - Points underneath each fuel tank to test for contamination like water or other debris.

SUPERSONIC - Speed of flight at or greater than Mach 1.0 (faster than the speed of sound).

SWEEPBACK - A backward inclination of an airfoil from root to tip in a way that causes the leading edge and often the trailing edge to meet relative wind obliquely, such as wingforms that are sweptback.

SWING-WING - A wing whose horizontal angle to the fuselage centerline can be adjusted in flight to vary aircraft motion at differing speeds.