S Sikorsky (model designator, e.g S-60).
SA Societe Anonyme (France, Romania), Sociedad Anonima (Brazil, Spain) or Spolka Akeyjna (Poland) (company constitution).
SAAF South African Air Force.
SAC Strategic Air Command.
safe-life A term denoting that a component has proved by testing that it can be expected to continue to function safely for a precisely defined period before replacement.
SALT/START Strategic Arms Limitation Talks/Strategic Arms Reduction Talks.
SAM Surface-to-air missile.
SAR (I) Search and rescue; (2) synthetic aperture radar.
SARH Semi-Active Radar Homing.
SAS Stability augmentation system.
satcom Satellite communications.
sawtooth Same as dog-tooth.
SCALP Systeme de Croisiere conventional Autonome a Longue Portee de precision – French derivative of APACHE weapon.
Sdn Bhd Sendirian Berhad (Malaysian company constitution).
SEAD Suppression of enemy air defence(s).
semi-active Homing on to radiation reflected from target illuminated by radar or laser energy beamed from elsewhere (for example, from launch aircraft).
sensitive altimeter Altitude indicator of mechanical type, having acute sensitivity.
SEPECAT Societe Europeane de Productin de l’Avion Ecolet et Combat Appui Tactique = European company to produce the [Jaguar] training and tactical combat aircraft. 50:50 Anglo-French company responsible for Jaguar, with BAC (now BAE Systems) and Breguet (now Dassault).
service ceiling Usually height equivalent to air density at which maximum attainable rate of climb is 100 ft/min.
servo A device which acts as a relay, usually augmenting the pilot's efforts to move a control surface, or the like.
sfc Specific fuel consumption (which see).
SFW Sensor-Fuzed Weapon.
shaft Connection between gas-turbine and compressor or other driven unit. Two-shaft engine has second shaft, rotating at different speed, surrounding the first (thus. HP surrounds inner LP or fanshaft).
shipment One item or consignment delivered (by any means of transport) to customer.
shp Shaft horsepower, measure of power transmitted via rotating shaft.
shroud Many meanings, including: (1) a fixed circular duct surrounding a fan or propfan; (2) a ring formed by lateral projections on a rotor (for example fan) blade (part-span or at the tip); (3) a portion of a wing or other fixed aerofoil projecting aft over the leading-edge of a hinged or otherwise movable surface such as a flap, aileron or elevator.
SI Système International (d’Unités). French abbreviation meaning International System of Units: an internationally accepted unit of measurement under the Système International d’Unités in science and technology. There are seven fundamental units: the metre, kilogram, second, ampere, kelvin, candela, and mole, and two supplementary units, the radian and steradian.
sideline noise EPNdB measure of aircraft landing and taking off, at point 0.25 n mile (2- or 3-engined) or 0.35 n mile (4-engined) from runway centreline.
sidestick Control column in the form of a short handgrip beside the pilot.
sigint Signals intelligence.
signature Characteristic 'fingerprint' of all acoustic or electromagnetic radiation (radar, IR, and so on).
single-aisle Passenger cabin has seats on each side of a single aisle along or near the centre.
single-shaft Gas-turbine in which all compressors and turbines are fixed to common shaft.
SIVAM Sistema de Vigilancia da Amazonia – Brazil’s surveillance programme for its Amazon region.
S/L Sea level.
SLAM Stand-off Land Attack Missile (US designation = AGM-84G).
SLAM-ER Stand-off Land Attack Missile – Expanded Response (US designation = AGM-84H).
SLAR Side-looking airborne radar.
slat Auxiliary curved or mini-aerofoil surface designed to prevent flow breakaway from a wing or tail. On a tail leading-edge it may be fixed, leaving a narrow slot. On a wing it is almost always retractable, normally flush with the wing profile but extended (under power or by aerodynamic lift) to leave a narrow slot for take-off, low-speed loiter or landing.
SLEP Service (or Structural) Life Extension Programme.
slot, slotted See slat.
SMD Stand-off Munitions Dispenser.
snap-down Air-to-air interception of low-flying aircraft by AAM fired from fighter at a higher altitude.
SNECMA Societe Nationale d’Etude et de Construction de Moteurs d’Aviation (France).
SOA Special Operations Aviation.
SOCAT Romanian acronym for the IAR-Brasov/Elbit upgrade of 24 IAR-330L Pumas with modern avionics and armament.
SOM Stand-Off Munitions.
SONAR, sonar Sound navigation and ranging.
SpA Societa per Azioni (Italian company constitution).
specific fuel consumption Rate at which fuel is consumed divided by power or thrust developed, and thus a measure of engine efficiency. For jet engines (air-breathing, not rockets) unit is mg/Ns, milligrams per Newton-second; for shaft engines unit is µg/J, micrograms (millionths of a gram) per Joule (SI unit of work or energy).
spoiler Plank-like surface normally recessed into top of wing, hinged up under power to reduce (spoil) lift and increase drag. Used asymmetrically for lateral control.
spoileron Small spoiler augmenting ailerons.
sportplane Light aircraft design in which performance takes precedence over utility.
Sp. z o.o Spolka z ograniczona odpowiedzialnoscia (Polish company constitution)
SRAM Short-Range Attack Missile.
Srl Societa Reponsibilita Limitata (Italian company constitution).
SSB Single-sideband (radio).
SSN Nuclear attack submarine.
SSR Secondary surveillance radar.
SST Supersonic transport.
st Static thrust.
stabilator One-piece, all-moving horizontal tail, combining functions of horizontal stabiliser and elevator.
stabilizer Tailplane (US); vertical stabilizer = fin.
stall Sudden near-total loss of lift of a wing because AoA has exceeded a critical value.
stall strips Sharp-edged strips on wing leading-edge to induce stall to initiate at that point.
stalling speed Airspeed at which aircraft stalls at 1 g.
starboard Right side, looking forward.
static inverter Solid-state (not rotary machine) inverter of alternating wave-form to produce DC from AC.
STC Supplementary Type Certificate.
stealth See low-observable
stick-pusher Stall-protection device that forces pilot's control column forward as stalling angle of attack is neared.
stick-shaker Stall-warning device that noisily shakes pilot's control column as stalling angle of attack is neared.
STO Short Take-Off.
STOL Short take-off and landing. (Several definitions, stipulating allowable horizontal distance to clear screen height of 35 or 50 ft or various SI measures.)
store Object carried as part of payload on external attachment (for example bomb, drop tank).
STOVL Short take-off, vertical landing.
strobe light High-intensity flashing beacon.
Su Sukhoi (Russian design bureau).
supercritical wing Wing of relatively deep, flat-topped profile generating lift right across upper surface instead of concentrated close behind leading-edge.
sweepback Backwards inclination of wing or other aerofoil, seen from above, measured relative to fuselage or other reference axis, usually measured at quarter chord (25 per cent) or at leading-edge.