Pilot/Controller Glossary 

9/5/24 

SIMULTANEOUS ILS APPROACHES

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 An approach system permitting simultaneous ILS approaches to 

airports having parallel runways separated by at least 4,300 feet between centerlines. Integral parts of a total 

system are ILS, radar, communications, ATC procedures, and appropriate airborne equipment. 

(See PARALLEL RUNWAYS.) 
(Refer to AIM.) 

SIMULTANEOUS OFFSET INSTRUMENT APPROACH (SOIA)

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 An instrument landing system comprised 

of an ILS PRM, RNAV PRM or GLS PRM approach to one runway and an offset LDA PRM with glideslope 

or an RNAV  PRM or GLS PRM approach utilizing vertical guidance to another where parallel runway spaced 

less than 3,000 feet and at least 750 feet apart. The approach courses converge by 2.5 to 3 degrees. Simultaneous 

close parallel PRM approach procedures apply up to the point where the approach course separation becomes 

3,000 feet, at the offset MAP. From the offset MAP to the runway threshold, visual separation by the aircraft 

conducting the offset approach is utilized. 

(Refer to AIM) 

SIMULTANEOUS (PARALLEL) DEPENDENT APPROACHES- An approach operation permitting 

ILS/RNAV/GLS approaches to adjacent parallel runways where prescribed diagonal spacing must be 

maintained.  Aircraft are not permitted to pass each other during simultaneous dependent operations. Integral 

parts of a total system ATC procedures, and appropriate airborne and ground based equipment. 
SINGLE DIRECTION ROUTES

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 Preferred IFR Routes which are sometimes depicted on high altitude en route 

charts and which are normally flown in one direction only. 

(See PREFERRED IFR ROUTES.) 
(Refer to CHART SUPPLEMENT U.S.) 

SINGLE FREQUENCY APPROACH

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 A service provided under a letter of agreement to military single-piloted 

turbojet aircraft which permits use of a single UHF frequency during approach for landing. Pilots will not 

normally be required to change frequency from the beginning of the approach to touchdown except that pilots 

conducting an en route descent are required to change frequency when control is transferred from the air route 

traffic control center to the terminal facility. The abbreviation “SFA” in the DoD FLIP IFR Supplement under 

“Communications” indicates this service is available at an aerodrome. 
SINGLE-PILOTED AIRCRAFT

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 A military turbojet aircraft possessing one set of flight controls, tandem 

cockpits, or two sets of flight controls but operated by one pilot is considered single-piloted by ATC when 

determining the appropriate air traffic service to be applied. 

(See SINGLE FREQUENCY APPROACH.) 

SKYSPOTTER

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 A pilot who has received specialized training in observing and reporting inflight weather 

phenomena. 
SLASH

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 A radar beacon reply displayed as an elongated target. 

SLDI

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(See SECTOR LIST DROP INTERVAL.) 

SLOW TAXI

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To taxi a float plane at low power or low RPM. 

SMALL UNMANNED AIRCRAFT SYSTEM (sUAS)– An unmanned aircraft weighing less than 55 pounds 

on takeoff, including everything that is on board or otherwise attached to the aircraft. 
SMAR

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(See SPECIAL MILITARY ACTIVITY ROUTE.) 

SN

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(See SYSTEM STRATEGIC NAVIGATION.) 

SPACE

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BASED ADS

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B (SBA)

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 A constellation of satellites that receives ADS

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B Out broadcasts and relays 

that information to the appropriate surveillance facility. The currently deployed SBA system is only capable of 

PCG S

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