UA.V.A.K4: Aeronautical advisory communication station (UNICOM) and associated communication

ACS Area V — Operations Task A: Radio Communications Procedures References: ACAdvisory CircularCloseFAA guidance that explains acceptable ways to comply with rules or understand FAA procedures. 107-2; AIMAeronautical Information ManualCloseFAA operational guidance and glossary material used to understand aviation procedures and terminology.; FAAFederal Aviation AdministrationCloseThe U.S. aviation regulator responsible for Part 107 rules, airspace, and pilot certification processes.-H-8083-25; FAAFederal Aviation AdministrationCloseThe U.S. aviation regulator responsible for Part 107 rules, airspace, and pilot certification processes.-G-8082-22

Key Concepts

UNICOM, CTAF, and Airport Advisory Basics

• UNICOMUniversal CommunicationsCloseA non-government communication station at some airports for local advisory information. is a nongovernment air/ground radio station that may provide airport information (weather, wind direction, recommended runway, other necessary information) at public-use airports without a control tower or FSSFlight Service StationCloseFAA-certified briefing support for weather, NOTAMs, and flight information.. When a UNICOMUniversal CommunicationsCloseA non-government communication station at some airports for local advisory information. frequency is designated as the Common Traffic Advisory Frequency (CTAFCommon Traffic Advisory FrequencyCloseThe frequency pilots use to self-announce near many non-towered airports.), it will be identified in aeronautical publications. The CTAFCommon Traffic Advisory FrequencyCloseThe frequency pilots use to self-announce near many non-towered airports. may also be a MULTICOMMulticomCloseA self-announce radio frequency used at some airports without another published frequency., FSSFlight Service StationCloseFAA-certified briefing support for weather, NOTAMs, and flight information., or tower frequency used for advisory practices at nontowered airports. Good practice is to transmit intentions on the CTAFCommon Traffic Advisory FrequencyCloseThe frequency pilots use to self-announce near many non-towered airports. even though two-way radio communications are not required at nontowered fields. The key is selecting the correct common frequency published for that airport^[5].
• When an FSSFlight Service StationCloseFAA-certified briefing support for weather, NOTAMs, and flight information. is providing CTAFCommon Traffic Advisory FrequencyCloseThe frequency pilots use to self-announce near many non-towered airports. services, first check the airport’s automated weather and establish two-way communications with the CTAFCommon Traffic Advisory FrequencyCloseThe frequency pilots use to self-announce near many non-towered airports. FSSFlight Service StationCloseFAA-certified briefing support for weather, NOTAMs, and flight information. before transmitting your outbound/inbound intentions. Inbound aircraft should initiate contact approximately 10 miles out and report identification and type, altitude, location relative to the airport, intentions (landing or overflight), possession of the automated weather, and request the airport advisory/information service^[3].
• Special advisory services exist at selected airports: Local Airport Advisory (LAALocal Airport AdvisoryCloseAn airport advisory service that can provide local traffic and airport information.) is available only in Alaska where an on-airport FSSFlight Service StationCloseFAA-certified briefing support for weather, NOTAMs, and flight information. provides the service; Remote Airport Information Service (RAISRemote Automated Information ServiceCloseA remote advisory or information service referenced in airport and flight service context.) may be provided for special events at nontowered airports upon airport authority request. CTAFCommon Traffic Advisory FrequencyCloseThe frequency pilots use to self-announce near many non-towered airports. details for LAALocal Airport AdvisoryCloseAn airport advisory service that can provide local traffic and airport information. locations are published^[3].

Practical Procedures in the Pattern and Local Area

• At nontowered airports, standard traffic patterns are entered at pattern altitude. From the downwind side, the preferred entry is a 45-degree course to midfield downwind. From the upwind side, one method is to cross midfield at least 500 feet above pattern altitude before maneuvering to join the pattern. Transmit clear, concise position and intention reports on CTAFCommon Traffic Advisory FrequencyCloseThe frequency pilots use to self-announce near many non-towered airports. to enhance situational awareness^[5].
• When departing the traffic pattern, continue straight out, or exit with a 45-degree turn (left for left traffic; right for right traffic) beyond the departure end after reaching pattern altitude. Do not continue on a track that penetrates the departure path of a parallel runway; ensure your advisory calls reflect your planned exit to deconflict with other traffic^[1].
• Pilots conducting operations other than arriving/departing (e.g., parachute operations, en route, practice maneuvers) should monitor/communicate on the appropriate frequency while within 10 miles of the airport, unless other procedures apply. This supports see-and-avoid with advisory traffic^[3].

Radio Equipment, Licensing, and Class C Entry

• Aviation VHFVery High FrequencyCloseRadio frequency band used for many aviation communications and broadcasts. radios operate between 118.0 and 136.975 MHz. Common sets are “720” or “760” channel radios using 0.025 MHz (25 kHz) spacing (e.g., 118.025, 118.050); the 720 models tune up to 135.975 MHz, while 760 models reach 136.975 MHz. VHFVery High FrequencyCloseRadio frequency band used for many aviation communications and broadcasts. is line-of-sight—greater altitude increases range. In the U.S., no pilot radio license is required domestically; international operation requires an FCCFederal Communications CommissionCloseThe U.S. agency that regulates radio spectrum and communications equipment. restricted radiotelephone permit. Most GA stations in the U.S. do not need a station license unless operating internationally, using non-VHFVery High FrequencyCloseRadio frequency band used for many aviation communications and broadcasts. radio, or meeting other criteria^[1].
• For Class C airspace, two-way radio communication must be established with the ATCAir Traffic ControlCloseThe system that manages controlled airspace, traffic flow, and aircraft separation services. facility prior to entry and then maintained. If ATCAir Traffic ControlCloseThe system that manages controlled airspace, traffic flow, and aircraft separation services. replies “(callsign) standby,” communications are established and entry is permitted; if ATCAir Traffic ControlCloseThe system that manages controlled airspace, traffic flow, and aircraft separation services. responds without using your identification, communications are not established and you may not enter. Be aware of the non-regulatory Class C “Outer Area,” normally 20 NMNautical MileCloseA distance unit used in aviation. One nautical mile is about 1.15 statute miles. from the primary airport, where approach control may provide services; it is not charted^[7].

Lost Communications: What to Know

• If two-way communications fail, exercise good judgment; if necessary, use emergency authority. A pilot may deviate from rules in Subparts A and B to the extent required by an emergency under 14 CFRCode of Federal RegulationsCloseThe federal rulebook where Part 107, Part 89, Part 48, and other aviation rules live. §91.3(b). When operating under IFRInstrument Flight RulesCloseRules for operating primarily by instruments. On the exam, IFR often appears in weather, traffic, and airspace context., unless you exercise emergency authority, comply with 14 CFRCode of Federal RegulationsCloseThe federal rulebook where Part 107, Part 89, Part 48, and other aviation rules live. §91.185 for routing and altitude in VFRVisual Flight RulesCloseRules for flight using visual reference and minimum weather conditions./IFRInstrument Flight RulesCloseRules for operating primarily by instruments. On the exam, IFR often appears in weather, traffic, and airspace context. conditions, as applicable^[6].
• If equipped with a coded radar beacon transponder, select Mode A/3 Code 7600 for lost communications. Attempt to reestablish contact on the last assigned frequency, or with an FSSFlight Service StationCloseFAA-certified briefing support for weather, NOTAMs, and flight information. or ARINCAeronautical Radio, IncorporatedCloseAviation communications service referenced in lost-communication and en route communication procedures.; if contact is made with FSS/ARINCFlight Service Station / ARINCCloseCommunication options referenced in lost-communication procedures., report your position, altitude, last assigned frequency, and request further clearance from the controlling facility. Use of 121.5 MHz is also acceptable if capable^[4].