- (CAA) Standing Advisory
Committee on Pilot Licensing.
SAR - search-and-rescue. Also Sarsat, SAR satellite.
SAS - stability augmentation system. An automatic flight
control system employed in many helicopters and some fixed-wing
aircraft to enhance their stability and handling qualities.
satcoms - satellite communications, now being introduced on
intercontinental airliners and business jets for (non- operational)
air-to-ground voice communications via ground relay stations.
SB - Service Bulletin. Advisory notices issued by aircraft,
engine and equipment manufacturers alerting owners and engineers to
faults or problems requiring preventative or remedial maintenance or
modification. Often termed 'mandatory', but do not have the legal
force of Airworthiness Directives (which see).
SBAC - Society of British Aerospace Companies. The UK aerospace
manufacturers' trade association.
SDAU - Safety Data Analysis Unit of the CAA.
Second pilot - Unofficial term used to describe short (usually
8-10 hours) flying courses designed to enable non-pilot light aircraft
passengers to take control and land in an emergency such as pilot
incapacitation. Also standby or safety pilot and pinch-hitter (U.S.)
Sectional - (U.S.) VFR navigation chart, equivalent to our
1:500,000 or 'half-million'
SELCAL - selective calling. A high-frequency system enabling
air traffic control to alert a particular aircraft, by means of
flashing light or aural signal in the cockpit, for receipt of a
message without the crew having to maintain a listening watch. Used on
long-haul over-ocean airline routes and by intercontinental bizjets.
Semi - circular - system of cruising altitudes.
sfc - specific fuel consumption of an engine, expressed in
pounds of fuel consumed for each unit of power (hp, shp, lb/st)
produced. Also surface.
shp - shaft horsepower.
SID - standard instrument departure. A standard IFR departure
route enabling air traffic controllers to issue abbreviated clearances
and thus speed the flow of traffic.
SIGMET - warning of severe weather conditions (active
thunderstorms, hail, severe turbulence, icing etc.) issued my Met
sl - sea level.
SMOH - since major overhaul. Term used in aircraft for sale
advertisements where engine hours are quoted (see TBO). Also STOH,
since top overhaul, TTSN, total time since new; TTAF/E, total time
SMR - surface movement radar.
SOB - souls on board, the number of persons on board an
aircraft. Also POB.
socked - in - A colloquialism referring to an airport closed to
air traffic by bad weather, similarly clamped.
SOP - standard operating procedure.
specific range - measure of an aircraft's fuel efficiency,
expressed as nautical miles flown per pound of fuel burned (nm/lb)
SPL - Student Pilot's Licence. No longer issued in the UK,
where a CAA medical certificate serves as an SPL.
squawk - to transmit an assigned code via a transponder (see
SR - sunrise.
SRA - Surveillance Radar Approach. Also Special Rules Area.
SRE - Surveillance Radar Element of a GCA.
SRZ - Special Rules Zone. An area of protected airspace
surrounding an airfield and extending from the surface upwards to a
specific level which affords safety to air traffic movements in the
vicinity of airfields whose traffic level does not warrant the
establishment of a Control Zone. Also SRA, Special Rules Area.
extending vertically and horizontally from a level above the surface,
but not necessarily terminating at the same upper level as the SRZ.
SS - sunset.
SSB - single sideband. Reduction of bandwidth by transmitting
only one sideband and suppressing the other, and usually also the
SSR - secondary surveillance radar. A radar system comprising a
ground-based transmitter/receiver which interrogates a compatible unit
in the aircraft (see transponder below), providing instant radar
identification without having to manoeuvre. Assigned four-digit
transponder codes are referred to as squawk codes.
STAR - Standard Terminal Arrival Route, for inbound IFR
STC - Supplemental Type Certificate. U.S. system for post-type
certification approval of aircraft modifications such as re- engining,
STOL kits, etc, where the full certification process is not deemed
necessary. Also used by manufacturers to certify (often greatly
changed) new models of old types under so-called 'grandfather rights'.
STOL - short take-off and landing. Also VTOL, vertical take-off
and landing; V/STOL, vertical/short take-off and landing; STOVL, short
take-off, vertical landing.