Spare Preferred = An item which is recommended as the current preferred spare for replenishment purposes.
The item may be preferred for any number of reasons but is commonly an item other than that utilized in earlier applications.

 Spare ready = An item which has been assembled to the point that it can be attached to an aircraft without further buildup or assembly other than that necessary to fit it to its unique position.

 Spares float = The quantity of individual items held (additional to those instalied on aircraft) for the purpose of providing replacements for those removed from aircraft for overhaul, repair or rectification.

 Spares range = The total number of different items individually identified by part number or description. It excludes any reference to quantities of individual items.

 Special Drawing Right (SDR) = A reserve asset used as a unit of account, as defined by the international Monetary Fund (IMF).

 Special rates = Rates that apply to traffic special conditions and usualiy at a limited number of cities. Examples of such rates are container rates, exception rating, surface-air rates, and import rates.

 Specitic Commodity Rate (SCR) = A rate applicable to carriage of specificaly designated commodities.

 Specification Maintenance = Definition of what tasks have to be performed, and when.

 Specification operations (Aircraft maintenance) = A document approved by the appropriate airworthiness authority which estabilshes an air carrier?s maintenance program and includes time control programs for aiframe, systems, engines, and components as required. This document is initiated by an air carrier and is official only after it has been approved by the appropriate airworthiness authority. it must be approved prior to operation of each airpiane type in scheduled service and sepately for each air carrier.

 Specified Rate = A rate specified in an IATA Cargo Tariff Coordinating Conference resolution.

 SPI = Special position identification pulse.

 SPIR = Single pilot instrument rating.

 Splint Charter = Where a number of consignments from different shippers are carried on the same non-scheduied aircraft. Under UK reguiations a non-scheduied fiight charterred by a singie forwarder or agent on behaif of a number of shippers is stili ciassified as a spiit charter. Under US reguiations, a forwarder chartered fiight is ciassified as a singie entity aithough it can consoiidate.

  sr = Steradian.

 SR = Storage-Destination (Charges Codes).

 SRR = Search and rescue region.

 SS = Reporting a sale.

 SS = Signature Service (Charges Code).

 SSB Singie sideband.

 SSPD = Shortshipped.

 SSR = Special Service Request.

 SSR = Secondary surveiiiance radar.

 SSR RPG = SSR Regionai Planning Group.

 SST = Supersonic Transport.

 SI = Stratus.

 ST = State Saies Tax (Charges Codes).

 Standard International Trade Classitication (SITC) = One of a

number of numerical commodity codes deveioped by the United

Nations. See Harmonized Commodity Description and Coding

System.

 Standard Isoharic Surlace = An isobaric surface used on a world-wide basis for representing and anaiysing the conditions in Ah.Q atmosphere.

 Standard receiver = The airborne receiver modei assumed in

partitioning the MLS error budgets. The saiient characteristics are:

1) signai processing based onthe measurement of beam centres;

2) negiigibie centring error;

3) controi motion noise (CMN) iess than or equai to the vaiues

contained in Pat 1,3.11.6.1.1.2;

4)   a 26 kHz bandwidth 2-poie Iow pass beam envelope filter; and

5) angle data output fiitering by a singie poie, iow pass fliter with a

corner frequency of 10 radians per second.

 STAP ICAO Statistics Panei.

 STAR = Standard (instrument) arrivai.

 State of manufacture = The State(s) responsibie for the certification as to the airworthiness of the prototype.

 State al Origin = The state in the territory of which the cargo was first ioaded on an aircraft.

State of Registry = The State on whose register the aircraft is entered.

 State al Operator = The state in which the operator has his principal piace of business or, if he has no such piace of business, his permanent residence.

 Station return la = The return of an aircraft to the airport of origin as a resuit of the maifunction or suspected maifunction of any item on the aircraft.

Note:   The term Air Turn Back refers to specific type of Air Interruption.

 Steradian (Sr) = The soiid angle which, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of iength equai to the radius of the sphere.

 Stap far nan-traffic purpases = A ianding for any purpose other than taking on or discharging passengers, cargo or mali.

 Staway = A defined rectangular area on the ground at the end of take-off run avaiiabie prepared as a suitabie area in which an aircraft can be stopped in the case of an abandoned take-off.

 Stores = Articies of a readiiy consumabie nature for use oor sale on board an aircraft during fiight, inciuding commissary suppiies.

 Structural repair manual (SRM) = A manual containing descriptive infomation for identification and repair of aircraft primary and secondary structure. The manuai provides operators of the repair procedures deveioped by the manufacturer or by operators.

 Struoture other = Structure which Is judged not to be a structurai significant item. ?Other Structure? Is defined b?th externaiiy and internaiiy within zonai boundaries.

 Study wark = The process of identifying required maintenance functions through anaiysis of a fixed or assumed design and determining the most effective means of accompiishing these functions.

 Subassembly = Two or more parts which form a portion of an assmbiy or component repiaceable as a whoie, but having a part or parts wich are individuaiiy repiaceabie.

 Supersanic aeroplano = An aeropiane incapable of sustaining ievei fiight at speeds exceeding fiight Mach number of 1.

 Subistitute = The action whereby an item Is removed and another item Is instaiied in its piace for any reason.

 Subistituition equiment (technical) = The assignment of an alternate type aircraft to replace the aircraft originaiiy assigned which had encountered a technicai probiem.

Subsystem = A major functionai portion of a system which contributes to operationai compieteness of the system.

 Supersede = New ibm ?supersedes? oid item when the iatter wiii entuaiiy be forced out of use. in regard to technicai data ?superseded? indicates the removai of ali or any part of the pubiication and the issuance of a revision.

 Supplier = An organization that seiis products for uso by the air transport industry. The products may include spare parts, information and Eiectronic Data Proccessing requirements.

 Supplies commodity = in respect to specific commodity rates, means materiais used up with the commodity but otherthan parts.

 SUPPS = Suppiementary procedures.

 Surface transportatian = Means road, raii or water transportation.

 Superplus = indicates a specified quantity of an item which Is over and above that required to met forecasted stock requirements in support of normai operations.

 Supplies = Forthe purpose of appiying specific commodity rates suppiies are: materials used up with the main articie, but other than parts.

 Surcharge, Value = A surcharge forthe carriage of cargo having a vaiue in excess of a specified amount per kiiogram.

 Surveillance radar = Radar equipment used to determine the position of an aircraft in range and azimuth.

 Synchronous aperatian = Operation in which the time intervai between code units is a constant.

 Synthetic fughi trainer = Any one of the foiiowing three types of apparatus in which fiight conditions are simuiated on the ground:

- A fiight simuiator, which provides an accurate representation of the fiight deck of a particuiar aircraft type to the extent that the mechanicai, eiectricai, eiectronic, etc, aircraft systems controi functions, the normai environment of fiight crew members, and the performance and characteristics of that type of aircraft aro reaiisticaiiy simuiated.

- A fiight procedures traine~ which provides a reaiistic fiight deck environment, and which simuiates instrument responses, simpie controi functions of mechanicai, eiectricai, e!ectronic, etc, aircraft systems, and the performance and fiight characteristics of aircraft of a particuiar ciass.

- A basis instrument fiight trainer, which Is equipped with appropriato instruments, and which simuiates the fiight deck environment of an aircraft in fiight in instrument fiight conditions.