Pilot/Controller Glossary PILOT/CONTROLLER GLOSSARY

2/28/19 Pilot/Controller Glossary PILOT/CONTROLLER GLOSSARY

PURPOSE a. This Glossary was compiled to promote a common understanding of the terms used in the Air Traffic Control system. It includes those terms which are intended for pilot/controller communications. Those terms most frequently used in pilot/controller communications are printed in bold italics. The definitions are primarily defined in an operational sense applicable to both users and operators of the National Airspace System. Use of the Glossary will preclude any misunderstandings concerning the system’s design, function, and purpose. b. Because of the international nature of flying, terms used in the Lexicon, published by the International Civil Aviation Organization (ICAO), are included when they differ from FAA definitions. These terms are followed by “[ICAO].” For the reader’s convenience, there are also cross references to related terms in other parts of the Glossary and to other documents, such as the Code of Federal Regulations (CFR) and the Aeronautical Information Manual (AIM). c. This Glossary will be revised, as necessary, to maintain a common understanding of the system. EXPLANATION OF CHANGES d. Terms Added: ICAO 3LD ICAO Term ICAO Three Letter Designator UNCONTROLLED AIRSPACE e. Terms Deleted: IFIM INTERNATIONAL FLIGHT INFORMATION MANUAL f. Terms Modified: CLASS G AIRSPACE INTERNATIONAL CIVIL AVIATION ORGANIZATION [ICAO] NOTICES TO AIRMEN PUBLICATION g. Editorial/format changes were made where necessary. Revision bars were not used due to the insignificant nature of the changes.

PCG−1

2/28/19 Pilot/Controller Glossary

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REMOVE PAGES DATED INSERT PAGES DATED PCG−1 ...... 9/13/18 PCG−1 ...... 2/28/19 PCG C−3 and PCG C−4...... 3/29/18 PCG C−3 and PCG C−4...... 2/28/19 PCG C−5 through PCG C−9 ...... 9/13/18 PCG C−5 through PCG C−9 ...... 2/28/19 PCG I−1 through PCG I−6...... 3/29/18 PCG PCG I−1 through PCG I−6 ...... 2/28/19 PCG N−3 ...... 9/13/18 PCG N−3 ...... 9/13/18 PCG N−4 ...... 9/13/18 PCG N−4 ...... 2/28/19 PCG U−1 ...... 3/29/18 PCG U−1 ...... 2/28/19

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2/28/193/29/18 Pilot/Controller Glossary

CLASS D AIRSPACE− a new clearance or cancel his/her IFR flight plan if not (See CONTROLLED AIRSPACE.) off by the specified time. (See ICAO term CLEARANCE VOID TIME.) CLASS E AIRSPACE− CLEARANCE VOID TIME [ICAO]− A time (See CONTROLLED AIRSPACE.) specified by an air traffic control unit at which a CLASS G AIRSPACE− Airspace that is not clearance ceases to be valid unless the aircraft designated in 14 CFR Part 71 as Class A, Class B, concerned has already taken action to comply Class C, Class D, or Class E controlled airspace is therewith. Class G (uncontrolled) airspace. CLEARED APPROACH− ATC authorization for an (See UNCONTROLLED AIRSPACE.) aircraft to execute any standard or special instrument CLEAR AIR TURBULENCE (CAT)− Turbulence approach procedure for that airport. Normally, an encountered in air where no clouds are present. This aircraft will be cleared for a specific instrument term is commonly applied to high-level turbulence approach procedure. associated with wind shear. CAT is often encountered (See CLEARED (Type of) APPROACH.) in the vicinity of the jet stream. (See INSTRUMENT APPROACH PROCEDURE.) (See WIND SHEAR.) (Refer to 14 CFR Part 91.) (See JET STREAM.) (Refer to AIM.) CLEAR OF THE RUNWAY− CLEARED (Type of) APPROACH− ATC authoriza- a. Taxiing aircraft, which is approaching a tion for an aircraft to execute a specific instrument runway, is clear of the runway when all parts of the approach procedure to an airport; e.g., “Cleared ILS aircraft are held short of the applicable runway Runway Three Six Approach.” holding position marking. (See APPROACH CLEARANCE.) b. A pilot or controller may consider an aircraft, (See INSTRUMENT APPROACH which is exiting or crossing a runway, to be clear of PROCEDURE.) the runway when all parts of the aircraft are beyond (Refer to 14 CFR Part 91.) the runway edge and there are no restrictions to its (Refer to AIM.) continued movement beyond the applicable runway CLEARED AS FILED− Means the aircraft is cleared holding position marking. to proceed in accordance with the route of flight filed c. Pilots and controllers shall exercise good in the flight plan. This clearance does not include the judgement to ensure that adequate separation exists altitude, DP, or DP Transition. between all aircraft on runways and taxiways at (See REQUEST FULL ROUTE CLEARANCE.) airports with inadequate runway edge lines or (Refer to AIM.) holding position markings. CLEARED FOR TAKEOFF− ATC authorization CLEARANCE− for an aircraft to depart. It is predicated on known traffic and known physical airport conditions. (See AIR TRAFFIC CLEARANCE.) CLEARED FOR THE OPTION− ATC authoriza- CLEARANCE LIMIT− The fix, point, or location to tion for an aircraft to make a touch-and-go, low which an aircraft is cleared when issued an air traffic approach, missed approach, stop and go, or full stop clearance. landing at the discretion of the pilot. It is normally (See ICAO term CLEARANCE LIMIT.) used in training so that an instructor can evaluate a CLEARANCE LIMIT [ICAO]− The point to which student’s performance under changing situations. an aircraft is granted an air traffic control clearance. Pilots should advise ATC if they decide to remain on the runway, of any delay in their stop and go, delay CLEARANCE VOID IF NOT OFF BY (TIME)− clearing the runway, or are unable to comply with the Used by ATC to advise an aircraft that the departure instruction(s). clearance is automatically canceled if takeoff is not (See OPTION APPROACH.) made prior to a specified time. The pilot must obtain (Refer to AIM.)

PCG C−3 Pilot/Controller Glossary 2/28/193/29/18

CLEARED THROUGH− ATC authorization for an CLOSED TRAFFIC− Successive operations involv- aircraft to make intermediate stops at specified ing takeoffs and landings or low approaches where airports without refiling a flight plan while en route the aircraft does not exit the traffic pattern. to the clearance limit. CLOUD− A cloud is a visible accumulation of minute water droplets and/or ice particles in the CLEARED TO LAND− ATC authorization for an atmosphere above the Earth’s surface. Cloud differs aircraft to land. It is predicated on known traffic and from ground fog, fog, or ice fog only in that the latter known physical airport conditions. are, by definition, in contact with the Earth’s surface. CLEARWAY− An area beyond the takeoff runway CLT− under the control of airport authorities within which (See CALCULATED LANDING TIME.) terrain or fixed obstacles may not extend above CLUTTER− In radar operations, clutter refers to the specified limits. These areas may be required for reception and visual display of radar returns caused certain turbine-powered operations and the size and by precipitation, chaff, terrain, numerous aircraft upward slope of the clearway will differ depending on targets, or other phenomena. Such returns may limit when the aircraft was certificated. or preclude ATC from providing services based on (Refer to 14 CFR Part 1.) radar. (See CHAFF.) CLIMB TO VFR− ATC authorization for an aircraft (See GROUND CLUTTER.) to climb to VFR conditions within Class B, C, D, and (See PRECIPITATION.) E surface areas when the only weather limitation is (See TARGET.) restricted visibility. The aircraft must remain clear of (See ICAO term RADAR CLUTTER.) clouds while climbing to VFR. CMNPS− (See SPECIAL VFR CONDITIONS.) (See CANADIAN MINIMUM NAVIGATION (Refer to AIM.) PERFORMANCE SPECIFICATION AIRSPACE.)

CLIMBOUT− That portion of flight operation COASTAL FIX− A navigation aid or intersection between takeoff and the initial cruising altitude. where an aircraft transitions between the domestic route structure and the oceanic route structure. CLIMB VIA– An abbreviated ATC clearance that CODES− The number assigned to a particular requires compliance with the procedure lateral path, multiple pulse reply signal transmitted by a associated speed restrictions, and altitude restrictions transponder. along the cleared route or procedure. (See DISCRETE CODE.)

CLOSE PARALLEL RUNWAYS− Two parallel COLD TEMPERATURE COMPENSATION− An runways whose extended centerlines are separated by action on the part of the pilot to adjust an aircraft’s less than 4,300 feet and at least 3000 feet (750 feet for indicated altitude due to the effect of cold SOIA operations) for which ATC is authorized to temperatures on true altitude above terrain versus conduct simultaneous independent approach opera- aircraft indicated altitude. The amount of tions. PRM and simultaneous close parallel appear in compensation required increases at a greater rate with approach title. Dual communications, special pilot a decrease in temperature and increase in height training, an Attention All Users Page (AAUP), NTZ above the reporting station. monitoring by displays that have aural and visual COLLABORATIVE TRAJECTORY OPTIONS alerting algorithms are required. A high update rate PROGRAM (CTOP)− CTOP is a traffic management surveillance sensor is required for certain runway or program administered by the Air Traffic Control approach course spacing. System Command Center (ATCSCC) that manages demand through constrained airspace, while consid- CLOSED RUNWAY− A runway that is unusable for ering operator preference with regard to both route aircraft operations. Only the airport management/ and delay as defined in a Trajectory Options Set military operations office can close a runway. (TOS).

PCG C−4 2/28/193/29/18 Pilot/Controller Glossary

COMBINED CENTER-RAPCON− An air traffic b. Middle Compass Locator (LMM)− A compass facility which combines the functions of an ARTCC locator installed at the site of the middle marker of an and a radar approach control facility. instrument landing system. (See AIR ROUTE TRAFFIC CONTROL (See MIDDLE MARKER.) CENTER.) (See ICAO term LOCATOR.) (See RADAR APPROACH CONTROL COMPASS ROSE− A circle, graduated in degrees, FACILITY.) printed on some charts or marked on the ground at an COMMON POINT− A significant point over which airport. It is used as a reference to either true or two or more aircraft will report passing or have magnetic direction. reported passing before proceeding on the same or COMPLY WITH RESTRICTIONS− An ATC diverging tracks. To establish/maintain longitudinal instruction that requires an aircraft being vectored separation, a controller may determine a common back onto an arrival or departure procedure to comply point not originally in the aircraft’s flight plan and with all altitude and/or speed restrictions depicted on then clear the aircraft to fly over the point. the procedure. This term may be used in lieu of (See SIGNIFICANT POINT.) repeating each remaining restriction that appears on the procedure. COMMON PORTION− (See COMMON ROUTE.) COMPOSITE FLIGHT PLAN− A flight plan which specifies VFR operation for one portion of flight and COMMON ROUTE− That segment of a North IFR for another portion. It is used primarily in American Route between the inland navigation military operations. facility and the coastal fix. (Refer to AIM.) OR COMPULSORY REPORTING POINTS− Reporting points which must be reported to ATC. They are COMMON ROUTE− Typically the portion of a designated on aeronautical charts by solid triangles or RNAV STAR between the en route transition end filed in a flight plan as fixes selected to define direct point and the runway transition start point; however, routes. These points are geographical locations the common route may only consist of a single point which are defined by navigation aids/fixes. Pilots that joins the en route and runway transitions. should discontinue position reporting over compul- COMMON TRAFFIC ADVISORY FREQUENCY sory reporting points when informed by ATC that (CTAF)− A frequency designed for the purpose of their aircraft is in “radar contact.” carrying out airport advisory practices while CONDITIONS NOT MONITORED− When an operating to or from an airport without an operating airport operator cannot monitor the condition of the control tower. The CTAF may be a UNICOM, movement area or airfield surface area, this Multicom, FSS, or tower frequency and is identified information is issued as a NOTAM. Usually in appropriate aeronautical publications. necessitated due to staffing, operating hours or other (See DESIGNATED COMMON TRAFFIC mitigating factors associated with airport operations. ADVISORY FREQUENCY (CTAF) AREA.) CONFIDENCE MANEUVER− A confidence man- (Refer to AC 90-42, Traffic Advisory Practices at euver consists of one or more turns, a climb or Airports Without Operating Control Towers.) descent, or other maneuver to determine if the pilot COMPASS LOCATOR− A low power, low or in command (PIC) is able to receive and comply with medium frequency (L/MF) radio beacon installed at ATC instructions. the site of the outer or middle marker of an instrument CONFLICT ALERT− A function of certain air traffic landing system (ILS). It can be used for navigation at control automated systems designed to alert radar distances of approximately 15 miles or as authorized controllers to existing or pending situations between in the approach procedure. tracked targets (known IFR or VFR aircraft) that a. Outer Compass Locator (LOM)− A compass require his/her immediate attention/action. locator installed at the site of the outer marker of an (See MODE C INTRUDER ALERT.) instrument landing system. CONFLICT RESOLUTION− The resolution of (See OUTER MARKER.) potential conflictions between aircraft that are radar

PCG C−5 Pilot/Controller Glossary 2/28/193/29/18

identified and in communication with ATC by other substances are present. A runway is contami- ensuring that radar targets do not touch. Pertinent nated with respect to rubber deposits or other traffic advisories shall be issued when this procedure friction-degrading substances when the average is applied. friction value for any 500-foot segment of the runway Note: This procedure shall not be provided utilizing within the ALD fails below the recommended mosaic radar systems. minimum friction level and the average friction value in the adjacent 500-foot segments falls below the CONFORMANCE− The condition established when maintenance planning friction level. an aircraft’s actual position is within the conformance region constructed around that aircraft at its position, CONTERMINOUS U.S.− The 48 adjoining States according to the trajectory associated with the and the District of Columbia. aircraft’s Current Plan. CONTINENTAL UNITED STATES− The 49 States located on the continent of North America and the CONFORMANCE REGION− A volume, bounded District of Columbia. laterally, vertically, and longitudinally, within which an aircraft must be at a given time in order to be in CONTINUE− When used as a control instruction conformance with the Current Plan Trajectory for that should be followed by another word or words aircraft. At a given time, the conformance region is clarifying what is expected of the pilot. Example: determined by the simultaneous application of the “continue taxi,” “continue descent,” “continue lateral, vertical, and longitudinal conformance inbound,” etc. bounds for the aircraft at the position defined by time CONTROL AREA [ICAO]− A controlled airspace and aircraft’s trajectory. extending upwards from a specified limit above the CONSOLAN− A low frequency, long-distance earth. NAVAID used principally for transoceanic naviga- CONTROL SECTOR− An airspace area of defined tions. horizontal and vertical dimensions for which a CONTACT− controller or group of controllers has air traffic control responsibility, normally within an air route a. Establish communication with (followed by the traffic control center or an approach control facility. name of the facility and, if appropriate, the frequency Sectors are established based on predominant traffic to be used). flows, altitude strata, and controller workload. Pilot b. A flight condition wherein the pilot ascertains communications during operations within a sector the attitude of his/her aircraft and navigates by visual are normally maintained on discrete frequencies reference to the surface. assigned to the sector. (See CONTACT APPROACH.) (See DISCRETE FREQUENCY.) (See RADAR CONTACT.) CONTROL SLASH− A radar beacon slash repre- CONTACT APPROACH− An approach wherein an senting the actual position of the associated aircraft. aircraft on an IFR flight plan, having an air traffic Normally, the control slash is the one closest to the control authorization, operating clear of clouds with interrogating radar beacon site. When ARTCC radar at least 1 mile flight visibility and a reasonable is operating in narrowband (digitized) mode, the expectation of continuing to the destination airport in control slash is converted to a target symbol. those conditions, may deviate from the instrument CONTROLLED AIRSPACE− An airspace of approach procedure and proceed to the destination defined dimensions within which air traffic control airport by visual reference to the surface. This service is provided to IFR flights and to VFR flights approach will only be authorized when requested by in accordance with the airspace classification. the pilot and the reported ground visibility at the a. Controlled airspace is a generic term that covers destination airport is at least 1 statute mile. Class A, Class B, Class C, Class D, and Class E (Refer to AIM.) airspace. CONTAMINATED RUNWAY− A runway is b. Controlled airspace is also that airspace within considered contaminated whenever standing water, which all aircraft operators are subject to certain pilot ice, snow, slush, frost in any form, heavy rubber, or qualifications, operating rules, and equipment

PCG C−6 2/28/193/29/18 Pilot/Controller Glossary requirements in 14 CFR Part 91 (for specific airspace. VFR aircraft are only separated from IFR operating requirements, please refer to 14 CFR aircraft within the airspace. Part 91). For IFR operations in any class of controlled (See OUTER AREA.) airspace, a pilot must file an IFR flight plan and 4. CLASS D− Generally, that airspace from the receive an appropriate ATC clearance. Each Class B, surface to 2,500 feet above the airport elevation Class C, and Class D airspace area designated for an (charted in MSL) surrounding those airports that airport contains at least one primary airport around have an operational control tower. The configuration which the airspace is designated (for specific of each Class D airspace area is individually tailored designations and descriptions of the airspace classes, and when instrument procedures are published, the please refer to 14 CFR Part 71). airspace will normally be designed to contain the c. Controlled airspace in the United States is procedures. Arrival extensions for instrument designated as follows: approach procedures may be Class D or Class E airspace. Unless otherwise authorized, each person 1. CLASS A− Generally, that airspace from must establish two-way radio communications with 18,000 feet MSL up to and including FL 600, the ATC facility providing air traffic services prior to including the airspace overlying the waters within 12 entering the airspace and thereafter maintain those nautical miles of the coast of the 48 contiguous States communications while in the airspace. No separation and Alaska. Unless otherwise authorized, all persons services are provided to VFR aircraft. must operate their aircraft under IFR. 5. CLASS E− Generally, if the airspace is not 2. CLASS B− Generally, that airspace from the Class A, Class B, Class C, or Class D, and it is surface to 10,000 feet MSL surrounding the nation’s controlled airspace, it is Class E airspace. Class E busiest airports in terms of airport operations or airspace extends upward from either the surface or a passenger enplanements. The configuration of each designated altitude to the overlying or adjacent Class B airspace area is individually tailored and controlled airspace. When designated as a surface consists of a surface area and two or more layers area, the airspace will be configured to contain all (some Class B airspace areas resemble upside-down instrument procedures. Also in this class are Federal wedding cakes), and is designed to contain all airways, airspace beginning at either 700 or 1,200 published instrument procedures once an aircraft feet AGL used to transition to/from the terminal or en enters the airspace. An ATC clearance is required for route environment, en route domestic, and offshore all aircraft to operate in the area, and all aircraft that airspace areas designated below 18,000 feet MSL. are so cleared receive separation services within the Unless designated at a lower altitude, Class E airspace. The cloud clearance requirement for VFR airspace begins at 14,500 MSL over the United operations is “clear of clouds.” States, including that airspace overlying the waters within 12 nautical miles of the coast of the 48 3. CLASS C− Generally, that airspace from the contiguous States and Alaska, up to, but not surface to 4,000 feet above the airport elevation including 18,000 feet MSL, and the airspace above (charted in MSL) surrounding those airports that FL 600. have an operational control tower, are serviced by a CONTROLLED AIRSPACE [ICAO]− An airspace radar approach control, and that have a certain of defined dimensions within which air traffic control number of IFR operations or passenger enplane- service is provided to IFR flights and to VFR flights ments. Although the configuration of each Class C in accordance with the airspace classification. area is individually tailored, the airspace usually Note: Controlled airspace is a generic term which consists of a surface area with a 5 nautical mile (NM) covers ATS airspace Classes A, B, C, D, and E. radius, a circle with a 10NM radius that extends no lower than 1,200 feet up to 4,000 feet above the CONTROLLED TIME OF ARRIVAL− Arrival time airport elevation, and an outer area that is not charted. assigned during a Traffic Management Program. This Each person must establish two-way radio commu- time may be modified due to adjustments or user nications with the ATC facility providing air traffic options. services prior to entering the airspace and thereafter CONTROLLER− maintain those communications while within the (See AIR TRAFFIC CONTROL SPECIALIST.)

PCG C−7 Pilot/Controller Glossary 2/28/193/29/18

CONTROLLER [ICAO]− A person authorized to unless authorized to conduct autoland operations. provide air traffic control services. Coupled instrument approaches are commonly flown to the allowable IFR weather minima established by CONTROLLER PILOT DATA LINK the operator or PIC, or flown VFR for training and COMMUNICATIONS (CPDLC)− A two−way safety. digital communications system that conveys textual air traffic control messages between controllers and COURSE− pilots using ground or satellite-based radio relay a. The intended direction of flight in the horizontal stations. plane measured in degrees from north. CONVECTIVE SIGMET− A weather advisory b. The ILS localizer signal pattern usually concerning convective weather significant to the specified as the front course or the back course. safety of all aircraft. Convective SIGMETs are issued (See BEARING.) for tornadoes, lines of thunderstorms, embedded (See INSTRUMENT LANDING SYSTEM.) thunderstorms of any intensity level, areas of (See RADIAL.) thunderstorms greater than or equal to VIP level 4 4 CPDLC− with an area coverage of /10 (40%) or more, and hail 3 (See CONTROLLER PILOT DATA LINK /4 inch or greater. COMMUNICATIONS.) (See AIRMET.) (See AWW.) CPL [ICAO]− (See CWA.) (See ICAO term CURRENT FLIGHT PLAN.) (See SIGMET.) CRITICAL ENGINE− The engine which, upon (Refer to AIM.) failure, would most adversely affect the performance CONVECTIVE SIGNIFICANT METEOROLOG- or handling qualities of an aircraft. ICAL INFORMATION− CROSS (FIX) AT (ALTITUDE)− Used by ATC (See CONVECTIVE SIGMET.) when a specific altitude restriction at a specified fix COORDINATES− The intersection of lines of is required. reference, usually expressed in degrees/minutes/ CROSS (FIX) AT OR ABOVE (ALTITUDE)− Used seconds of latitude and longitude, used to determine by ATC when an altitude restriction at a specified fix position or location. is required. It does not prohibit the aircraft from COORDINATION FIX− The fix in relation to which crossing the fix at a higher altitude than specified; facilities will handoff, transfer control of an aircraft, however, the higher altitude may not be one that will or coordinate flight progress data. For terminal violate a succeeding altitude restriction or altitude facilities, it may also serve as a clearance for arriving assignment. aircraft. (See ALTITUDE RESTRICTION.) COPTER− (Refer to AIM.) (See HELICOPTER.) CROSS (FIX) AT OR BELOW (ALTITUDE)− Used by ATC when a maximum crossing altitude at CORRECTION− An error has been made in the a specific fix is required. It does not prohibit the transmission and the correct version follows. aircraft from crossing the fix at a lower altitude; COUPLED APPROACH− An instrument approach however, it must be at or above the minimum IFR performed by the aircraft autopilot, and/or visually altitude. depicted on the flight director, which is receiving (See ALTITUDE RESTRICTION.) position information and/or steering commands from (See MINIMUM IFR ALTITUDES.) onboard navigational equipment. In general, coupled (Refer to 14 CFR Part 91.) non-precision approaches must be flown manually (autopilot disengaged) at altitudes lower than 50 feet CROSSWIND− AGL below the minimum descent altitude, and a. When used concerning the traffic pattern, the coupled precision approaches must be flown word means “crosswind leg.” manually (autopilot disengaged) below 50 feet AGL (See TRAFFIC PATTERN.)

PCG C−8 2/28/193/29/18 Pilot/Controller Glossary

b. When used concerning wind conditions, the constant altitude and should not be confused with a word means a wind not parallel to the runway or the cruise clearance. path of an aircraft. (See ALTITUDE.) (See CROSSWIND COMPONENT.) (See ICAO term CRUISING LEVEL.) CROSSWIND COMPONENT− The wind compo- CRUISING LEVEL− nent measured in knots at 90 degrees to the (See CRUISING ALTITUDE.) longitudinal axis of the runway. CRUISING LEVEL [ICAO]− A level maintained CRUISE− Used in an ATC clearance to authorize a during a significant portion of a flight. pilot to conduct flight at any altitude from the minimum IFR altitude up to and including the CT MESSAGE− An EDCT time generated by the altitude specified in the clearance. The pilot may ATCSCC to regulate traffic at arrival airports. level off at any intermediate altitude within this block Normally, a CT message is automatically transferred of airspace. Climb/descent within the block is to be from the traffic management system computer to the made at the discretion of the pilot. However, once the NAS en route computer and appears as an EDCT. In pilot starts descent and verbally reports leaving an the event of a communication failure between the altitude in the block, he/she may not return to that traffic management system computer and the NAS, altitude without additional ATC clearance. Further, it the CT message can be manually entered by the TMC is approval for the pilot to proceed to and make an at the en route facility. approach at destination airport and can be used in CTA− conjunction with: (See CONTROLLED TIME OF ARRIVAL.) a. An airport clearance limit at locations with a (See ICAO term CONTROL AREA.) standard/special instrument approach procedure. The CFRs require that if an instrument letdown to an CTAF− airport is necessary, the pilot shall make the letdown (See COMMON TRAFFIC ADVISORY in accordance with a standard/special instrument FREQUENCY.) approach procedure for that airport, or CTAS− b. An airport clearance limit at locations that are (See CENTER TRACON AUTOMATION within/below/outside controlled airspace and with- SYSTEM.) out a standard/special instrument approach procedure. Such a clearance is NOT AUTHORIZA- CTOP− TION for the pilot to descend under IFR conditions (See COLLABORATIVE TRAJECTORY below the applicable minimum IFR altitude nor does OPTIONS PROGRAM) it imply that ATC is exercising control over aircraft in Class G airspace; however, it provides a means for CTRD− the aircraft to proceed to destination airport, descend, (See CERTIFIED TOWER RADAR DISPLAY.) and land in accordance with applicable CFRs CURRENT FLIGHT PLAN [ICAO]− The flight governing VFR flight operations. Also, this provides plan, including changes, if any, brought about by search and rescue protection until such time as the subsequent clearances. IFR flight plan is closed. (See INSTRUMENT APPROACH CURRENT PLAN− The ATC clearance the aircraft PROCEDURE.) has received and is expected to fly. CRUISE CLIMB− A climb technique employed by CVFP APPROACH− aircraft, usually at a constant power setting, resulting (See CHARTED VISUAL FLIGHT PROCEDURE in an increase of altitude as the aircraft weight APPROACH.) decreases. CWA− CRUISING ALTITUDE− An altitude or flight level (See CENTER WEATHER ADVISORY and maintained during en route level flight. This is a WEATHER ADVISORY.)

PCG C−9

2/28/193/29/18 Pilot/Controller Glossary I

I SAY AGAIN− The message will be repeated. b. Light− The rate of accumulation may create a problem if flight is prolonged in this environment IAF− (over 1 hour). Occasional use of deicing/anti-icing (See INITIAL APPROACH FIX.) equipment removes/prevents accumulation. It does IAP− not present a problem if the deicing/anti-icing (See INSTRUMENT APPROACH equipment is used. PROCEDURE.) c. Moderate− The rate of accumulation is such that IAWP− Initial Approach Waypoint even short encounters become potentially hazardous and use of deicing/anti-icing equipment or flight ICAO− diversion is necessary. (See ICAO Term INTERNATIONAL CIVIL d. Severe− The rate of ice accumulation is such AVIATION ORGANIZATION.) that ice protection systems fail to remove the ICAO 3LD− accumulation of ice, or ice accumulates in locations (See ICAO Term ICAO Three−Letter Designator) not normally prone to icing, such as areas aft of protected surfaces and any other areas identified by ICAO Three−Letter Designator (3LD)− An ICAO the manufacturer. Immediate exit from the condition 3LD is an exclusive designator that, when used is necessary. together with a flight number, becomes the aircraft call sign and provides distinct aircraft identification Note: to air traffic control (ATC). ICAO approves 3LDs to Severe icing is aircraft dependent, as are the other categories of icing intensity. Severe icing may enhance the safety and security of the air traffic occur at any ice accumulation rate. system. An ICAO 3LD may be assigned to a company, agency, or organization and is used instead IDENT− A request for a pilot to activate the aircraft of the aircraft registration number for ATC transponder identification feature. This will help the operational and security purposes. An ICAO 3LD is controller to confirm an aircraft identity or to identify also used for aircraft identification in the flight plan an aircraft. and associated messages and can be used for (Refer to AIM.) domestic and international flights. A telephony IDENT FEATURE− The special feature in the Air associated with an ICAO 3LD is used for radio Traffic Control Radar Beacon System (ATCRBS) communication. equipment. It is used to immediately distinguish one ICING− The accumulation of airframe ice. displayed beacon target from other beacon targets. (See IDENT.) Types of icing are: a. Rime Ice− Rough, milky, opaque ice formed by IDENTIFICATION [ICAO]− The situation which the instantaneous freezing of small supercooled exists when the position indication of a particular water droplets. aircraft is seen on a situation display and positively identified. b. Clear Ice− A glossy, clear, or translucent ice formed by the relatively slow freezing or large IF− supercooled water droplets. (See INTERMEDIATE FIX.) c. Mixed− A mixture of clear ice and rime ice. IF NO TRANSMISSION RECEIVED FOR Intensity of icing: (TIME)− Used by ATC in radar approaches to prefix procedures which should be followed by the pilot in a. Trace− Ice becomes perceptible. Rate of event of lost communications. accumulation is slightly greater than the rate of (See LOST COMMUNICATIONS.) sublimation. Deicing/anti-icing equipment is not utilized unless encountered for an extended period of IFR− time (over 1 hour). (See INSTRUMENT FLIGHT RULES.)

PCG I−1 Pilot/Controller Glossary 2/28/193/29/18

IFR AIRCRAFT− An aircraft conducting flight in designated (in conjunction with a TAA) this accordance with instrument flight rules. waypoint will be used as an IAWP when approaching the airport from certain directions, and as an IFWP IFR CONDITIONS− Weather conditions below the when beginning the approach from another IAWP. minimum for flight under visual flight rules. (See INSTRUMENT METEOROLOGICAL IFWP− Intermediate Fix Waypoint CONDITIONS.) ILS− IFR DEPARTURE PROCEDURE− (See INSTRUMENT LANDING SYSTEM.) (See IFR TAKEOFF MINIMUMS AND ILS CATEGORIES− 1. Category I. An ILS approach DEPARTURE PROCEDURES.) procedure which provides for approach to a height (Refer to AIM.) above touchdown of not less than 200 feet and with runway visual range of not less than 1,800 feet.− IFR FLIGHT− 2. Special Authorization Category I. An ILS (See IFR AIRCRAFT.) approach procedure which provides for approach to IFR LANDING MINIMUMS− a height above touchdown of not less than 150 feet (See LANDING MINIMUMS.) and with runway visual range of not less than 1,400 feet, HUD to DH. 3. Category II. An ILS approach IFR MILITARY TRAINING ROUTES (IR)− Routes procedure which provides for approach to a height used by the Department of Defense and associated above touchdown of not less than 100 feet and with Reserve and Air Guard units for the purpose of runway visual range of not less than 1,200 feet (with conducting low-altitude navigation and tactical autoland or HUD to touchdown and noted on training in both IFR and VFR weather conditions authorization, RVR 1,000 feet).− 4. Special below 10,000 feet MSL at airspeeds in excess of 250 Authorization Category II with Reduced Lighting. knots IAS. An ILS approach procedure which provides for IFR TAKEOFF MINIMUMS AND DEPARTURE approach to a height above touchdown of not less PROCEDURES− Title 14 Code of Federal than 100 feet and with runway visual range of not less Regulations Part 91, prescribes standard takeoff rules than 1,200 feet with autoland or HUD to touchdown for certain civil users. At some airports, obstructions and noted on authorization (no touchdown zone and or other factors require the establishment of centerline lighting are required).− 5. Category III: nonstandard takeoff minimums, departure proce- a. IIIA.−An ILS approach procedure which dures, or both to assist pilots in avoiding obstacles provides for approach without a decision height during climb to the minimum en route altitude. Those minimum and with runway visual range of not less airports are listed in FAA/DOD Instrument Approach than 700 feet. Procedures (IAPs) Charts under a section entitled b. IIIB.−An ILS approach procedure which “IFR Takeoff Minimums and Departure Procedures.” provides for approach without a decision height The FAA/DOD IAP chart legend illustrates the minimum and with runway visual range of not less symbol used to alert the pilot to nonstandard takeoff than 150 feet. minimums and departure procedures. When depart- c. IIIC.−An ILS approach procedure which ing IFR from such airports or from any airports where provides for approach without a decision height there are no departure procedures, DPs, or ATC minimum and without runway visual range facilities available, pilots should advise ATC of any minimum. departure limitations. Controllers may query a pilot ILS PRM APPROACH− An instrument landing to determine acceptable departure directions, turns, system (ILS) approach conducted to parallel runways or headings after takeoff. Pilots should be familiar whose extended centerlines are separated by less than with the departure procedures and must assure that 4,300 feet and at least 3,000 feet where independent their aircraft can meet or exceed any specified climb closely spaced approaches are permitted. Also used gradients. in conjunction with an LDA PRM, RNAV PRM or IF/IAWP− Intermediate Fix/Initial Approach Way- GLS PRM approach to conduct Simultaneous Offset point. The waypoint where the final approach course Instrument Approach (SOIA) operations. No of a T approach meets the crossbar of the T. When Transgression Zone (NTZ) monitoring is required to

PCG I−2 2/28/193/29/18 Pilot/Controller Glossary

conduct these approaches. ATC utilizes an enhanced INITIAL APPROACH SEGMENT [ICAO]− That display with alerting and, with certain runway segment of an instrument approach procedure spacing, a high update rate PRM surveillance sensor. between the initial approach fix and the intermediate Use of a secondary monitor frequency, pilot PRM approach fix or, where applicable, the final approach training, and publication of an Attention All Users fix or point. Page are also required for all PRM approaches. INLAND NAVIGATION FACILITY− A navigation (Refer to AIM) aid on a North American Route at which the common IM− route and/or the noncommon route begins or ends. (See INNER MARKER.) INNER MARKER− A marker beacon used with an ILS (CAT II) precision approach located between the IMC− middle marker and the end of the ILS runway, (See INSTRUMENT METEOROLOGICAL transmitting a radiation pattern keyed at six dots per CONDITIONS.) second and indicating to the pilot, both aurally and IMMEDIATELY− Used by ATC or pilots when such visually, that he/she is at the designated decision action compliance is required to avoid an imminent height (DH), normally 100 feet above the touchdown situation. zone elevation, on the ILS CAT II approach. It also marks progress during a CAT III approach. INCERFA (Uncertainty Phase) [ICAO]− A situation wherein uncertainty exists as to the safety of an (See INSTRUMENT LANDING SYSTEM.) (Refer to AIM.) aircraft and its occupants. INNER MARKER BEACON− INCREASED SEPARATION REQUIRED (ISR)– (See INNER MARKER.) Indicates the confidence level of the track requires 5NM separation. 3NM separation, 1 1/2NM INREQ− separation, and target resolution cannot be used. (See INFORMATION REQUEST.) INS− INCREASE SPEED TO (SPEED)− (See INERTIAL NAVIGATION SYSTEM.) (See SPEED ADJUSTMENT.) INSTRUMENT APPROACH− INERTIAL NAVIGATION SYSTEM (INS)− An (See INSTRUMENT APPROACH RNAV system which is a form of self-contained PROCEDURE.) navigation. INSTRUMENT APPROACH OPERATIONS (See Area Navigation/RNAV.) [ICAO]− An approach and landing using instruments INFLIGHT REFUELING− for navigation guidance based on an instrument (See AERIAL REFUELING.) approach procedure. There are two methods for executing instrument approach operations: INFLIGHT WEATHER ADVISORY− a. A two−dimensional (2D) instrument approach (See WEATHER ADVISORY.) operation, using lateral navigation guidance only; INFORMATION REQUEST (INREQ)− A request and originated by an FSS for information concerning an b. A three−dimensional (3D) instrument approach overdue VFR aircraft. operation, using both lateral and vertical navigation guidance. INITIAL APPROACH FIX (IAF)− The fixes depicted on instrument approach procedure charts Note: Lateral and vertical navigation guidance refers to the guidance provided either by: that identify the beginning of the initial approach a) a ground−based radio navigation aid; or segment(s). b) computer−generated navigation data from (See FIX.) ground−based, space−based, self−contained (See SEGMENTS OF AN INSTRUMENT navigation aids or a combination of these. APPROACH PROCEDURE.) (See ICAO term INSTRUMENT APPROACH INITIAL APPROACH SEGMENT− PROCEDURE.) (See SEGMENTS OF AN INSTRUMENT INSTRUMENT APPROACH PROCEDURE− A APPROACH PROCEDURE.) series of predetermined maneuvers for the orderly

PCG I−3 Pilot/Controller Glossary 2/28/193/29/18

transfer of an aircraft under instrument flight INSTRUMENT DEPARTURE PROCEDURE (DP) conditions from the beginning of the initial approach CHARTS− to a landing or to a point from which a landing may (See AERONAUTICAL CHART.) be made visually. It is prescribed and approved for a INSTRUMENT FLIGHT RULES (IFR)− Rules specific airport by competent authority. governing the procedures for conducting instrument (See SEGMENTS OF AN INSTRUMENT flight. Also a term used by pilots and controllers to APPROACH PROCEDURE.) indicate type of flight plan. (Refer to 14 CFR Part 91.) (See INSTRUMENT METEOROLOGICAL (Refer to AIM.) CONDITIONS.) a. U.S. civil standard instrument approach (See VISUAL FLIGHT RULES.) procedures are approved by the FAA as prescribed (See VISUAL METEOROLOGICAL under 14 CFR Part 97 and are available for public CONDITIONS.) use. (See ICAO term INSTRUMENT FLIGHT b. U.S. military standard instrument approach RULES.) procedures are approved and published by the (Refer to AIM.) Department of Defense. INSTRUMENT FLIGHT RULES [ICAO]− A set of c. Special instrument approach procedures are rules governing the conduct of flight under approved by the FAA for individual operators but are instrument meteorological conditions. not published in 14 CFR Part 97 for public use. INSTRUMENT LANDING SYSTEM (ILS)− A (See ICAO term INSTRUMENT APPROACH precision instrument approach system which normal- PROCEDURE.) ly consists of the following electronic components INSTRUMENT APPROACH PROCEDURE and visual aids: [ICAO]− A series of predetermined maneuvers by a. Localizer. reference to flight instruments with specified (See LOCALIZER.) protection from obstacles from the initial approach b. Glideslope. fix, or where applicable, from the beginning of a (See GLIDESLOPE.) defined arrival route to a point from which a landing c. Outer Marker. can be completed and thereafter, if a landing is not (See OUTER MARKER.) completed, to a position at which holding or en route d. Middle Marker. obstacle clearance criteria apply. (See MIDDLE MARKER.) (See ICAO term INSTRUMENT APPROACH e. Approach Lights. OPERATIONS) (See AIRPORT LIGHTING.) INSTRUMENT APPROACH PROCEDURE (Refer to 14 CFR Part 91.) CHARTS− (Refer to AIM.) (See AERONAUTICAL CHART.) INSTRUMENT METEOROLOGICAL CONDI- INSTRUMENT DEPARTURE PROCEDURE TIONS (IMC)− Meteorological conditions expressed (DP)− A preplanned instrument flight rule (IFR) in terms of visibility, distance from cloud, and ceiling departure procedure published for pilot use, in less than the minima specified for visual meteorolog- graphic or textual format, that provides obstruction ical conditions. clearance from the terminal area to the appropriate en (See INSTRUMENT FLIGHT RULES.) route structure. There are two types of DP, Obstacle (See VISUAL FLIGHT RULES.) Departure Procedure (ODP), printed either textually (See VISUAL METEOROLOGICAL or graphically, and, Standard Instrument Departure CONDITIONS.) (SID), which is always printed graphically. INSTRUMENT RUNWAY− A runway equipped (See IFR TAKEOFF MINIMUMS AND with electronic and visual navigation aids for which DEPARTURE PROCEDURES.) a precision or nonprecision approach procedure (See OBSTACLE DEPARTURE PROCEDURES.) having straight-in landing minimums has been (See STANDARD INSTRUMENT DEPARTURES.) approved. (Refer to AIM.) (See ICAO term INSTRUMENT RUNWAY.)

PCG I−4 2/28/193/29/18 Pilot/Controller Glossary

INSTRUMENT RUNWAY [ICAO]− One of the procedure and the final approach fix or point, as following types of runways intended for the appropriate. operation of aircraft using instrument approach INTERMEDIATE FIX− The fix that identifies the procedures: beginning of the intermediate approach segment of an a. Nonprecision Approach Runway− An instru- instrument approach procedure. The fix is not ment runway served by visual aids and a nonvisual normally identified on the instrument approach chart aid providing at least directional guidance adequate as an intermediate fix (IF). for a straight-in approach. (See SEGMENTS OF AN INSTRUMENT b. Precision Approach Runway, Category I− An APPROACH PROCEDURE.) instrument runway served by ILS and visual aids INTERMEDIATE LANDING− On the rare occasion intended for operations down to 60 m (200 feet) that this option is requested, it should be approved. decision height and down to an RVR of the order of The departure center, however, must advise the 800 m. ATCSCC so that the appropriate delay is carried over c. Precision Approach Runway, Category II− An and assigned at the intermediate airport. An instrument runway served by ILS and visual aids intermediate landing airport within the arrival center intended for operations down to 30 m (100 feet) will not be accepted without coordination with and decision height and down to an RVR of the order of the approval of the ATCSCC. 400 m. INTERNATIONAL AIRPORT− Relating to interna- d. Precision Approach Runway, Category III− An tional flight, it means: instrument runway served by ILS to and along the a. An airport of entry which has been designated surface of the runway and: by the Secretary of Treasury or Commissioner of 1. Intended for operations down to an RVR of Customs as an international airport for customs the order of 200 m (no decision height being service. applicable) using visual aids during the final phase of b. A landing rights airport at which specific landing; permission to land must be obtained from customs 2. Intended for operations down to an RVR of authorities in advance of contemplated use. the order of 50 m (no decision height being c. Airports designated under the Convention on applicable) using visual aids for taxiing; International Civil Aviation as an airport for use by 3. Intended for operations without reliance on international commercial air transport and/or interna- visual reference for landing or taxiing. tional general aviation. Note 1: See Annex 10 Volume I, Part I, Chapter 3, (See ICAO term INTERNATIONAL AIRPORT.) for related ILS specifications. (Refer to Chart Supplement U.S.) Note 2:Visual aids need not necessarily be INTERNATIONAL AIRPORT [ICAO]− Any airport matched to the scale of nonvisual aids provided. designated by the Contracting State in whose The criterion for the selection of visual aids is the territory it is situated as an airport of entry and conditions in which operations are intended to be conducted. departure for international air traffic, where the formalities incident to customs, immigration, public INTEGRITY− The ability of a system to provide health, animal and plant quarantine and similar timely warnings to users when the system should not procedures are carried out. be used for navigation. INTERNATIONAL CIVIL AVIATION ORGA- INTERMEDIATE APPROACH SEGMENT− NIZATION [ICAO]− A specialized agency of the (See SEGMENTS OF AN INSTRUMENT United Nations whose objective is to develop the APPROACH PROCEDURE.) principles and techniques of international air INTERMEDIATE APPROACH SEGMENT navigation and to foster planning and development of [ICAO]− That segment of an instrument approach international civil air transport. procedure between either the intermediate approach INTERROGATOR− The ground-based surveillance fix and the final approach fix or point, or between the radar beacon transmitter-receiver, which normally end of a reversal, race track or dead reckoning track scans in synchronism with a primary radar,

PCG I−5 Pilot/Controller Glossary 2/28/193/29/18

transmitting discrete radio signals which repetitious- b. Used to describe the point where two runways, ly request all transponders on the mode being used to a runway and a taxiway, or two taxiways cross or reply. The replies received are mixed with the meet. primary radar returns and displayed on the same plan INTERSECTION DEPARTURE− A departure from position indicator (radar scope). Also, applied to the any runway intersection except the end of the runway. airborne element of the TACAN/DME system. (See INTERSECTION.) (See TRANSPONDER.) (Refer to AIM.) INTERSECTION TAKEOFF− (See INTERSECTION DEPARTURE.) INTERSECTING RUNWAYS− Two or more IR− runways which cross or meet within their lengths. (See IFR MILITARY TRAINING ROUTES.) (See INTERSECTION.) IRREGULAR SURFACE− A surface that is open for INTERSECTION− use but not per regulations. a. A point defined by any combination of courses, ISR− radials, or bearings of two or more navigational aids. (See INCREASED SEPARATION REQUIRED.)

PCG I−6 9/13/183/29/18 Pilot/Controller Glossary

a. Nonradar Approach. Used to describe NORMAL OPERATING ZONE (NOZ)− The NOZ instrument approaches for which course guidance on is the operating zone within which aircraft flight final approach is not provided by ground-based remains during normal independent simultaneous precision or surveillance radar. Radar vectors to the parallel ILS approaches. final approach course may or may not be provided by NORTH AMERICAN ROUTE− A numerically ATC. Examples of nonradar approaches are VOR, coded route preplanned over existing airway and NDB, TACAN, ILS, RNAV, and GLS approaches. route systems to and from specific coastal fixes (See FINAL APPROACH COURSE.) serving the North Atlantic. North American Routes (See FINAL APPROACH-IFR.) consist of the following: (See INSTRUMENT APPROACH a. Common Route/Portion. That segment of a PROCEDURE.) North American Route between the inland navigation (See RADAR APPROACH.) facility and the coastal fix. b. Nonradar Approach Control. An ATC facility b. Noncommon Route/Portion. That segment of a providing approach control service without the use of North American Route between the inland navigation radar. facility and a designated North American terminal. (See APPROACH CONTROL FACILITY.) c. Inland Navigation Facility. A navigation aid on (See APPROACH CONTROL SERVICE.) a North American Route at which the common route c. Nonradar Arrival. An aircraft arriving at an and/or the noncommon route begins or ends. airport without radar service or at an airport served by d. Coastal Fix. A navigation aid or intersection a radar facility and radar contact has not been where an aircraft transitions between the domestic established or has been terminated due to a lack of route structure and the oceanic route structure. radar service to the airport. NORTH AMERICAN ROUTE PROGRAM (NRP)− (See RADAR ARRIVAL.) The NRP is a set of rules and procedures which are (See RADAR SERVICE.) designed to increase the flexibility of user flight d. Nonradar Route. A flight path or route over planning within published guidelines. which the pilot is performing his/her own navigation. NORTH ATLANTIC HIGH LEVEL AIRSPACE The pilot may be receiving radar separation, radar (NAT HLA)− That volume of airspace (as defined in monitoring, or other ATC services while on a ICAO Document 7030) between FL 285 and FL 420 nonradar route. within the Oceanic Control Areas of Bodo Oceanic, (See RADAR ROUTE.) Gander Oceanic, New York Oceanic East, Reykjavik, e. Nonradar Separation. The spacing of aircraft in Santa Maria, and Shanwick, excluding the Shannon accordance with established minima without the use and Brest Ocean Transition Areas. ICAO Doc 007 of radar; e.g., vertical, lateral, or longitudinal North Atlantic Operations and Airspace Manual separation. provides detailed information on related aircraft and (See RADAR SEPARATION.) operational requirements. NORTH MARK− A beacon data block sent by the NON−RESTRICTIVE ROUTING (NRR)− Portions host computer to be displayed by the ARTS on a 360 of a proposed route of flight where a user can flight degree bearing at a locally selected radar azimuth and plan the most advantageous flight path with no distance. The North Mark is used to ensure correct requirement to make reference to ground−based range/azimuth orientation during periods of NAVAIDs. CENRAP. NOPAC− NORTH PACIFIC− An organized route system (See NORTH PACIFIC.) between the Alaskan west coast and Japan.

NORDO (No Radio)− Aircraft that cannot or do not NOT STANDARD− Varying from what is expected communicate by radio when radio communication is or published. For use in NOTAMs only. required are referred to as “NORDO.” NOT STD- (See LOST COMMUNICATIONS.) (See NOT STANDARD.)

PCG N−3 Pilot/Controller Glossary 2/28/193/29/18

NOTAM− c. FDC NOTAM− A NOTAM regulatory in (See NOTICE TO AIRMEN.) nature, transmitted by USNOF and given system wide dissemination. NOTAM [ICAO]− A notice containing information (See ICAO term NOTAM.) concerning the establishment, condition or change in any aeronautical facility, service, procedure or NOTICES TO AIRMEN PUBLICATION− A hazard, the timely knowledge of which is essential to publication issued every 28 days, designed primarily personnel concerned with flight operations. for the pilot, which contains NOTAMs, graphic notices, and other information considered essential to a. I Distribution− Distribution by means of the safety of flight as well as supplemental data to telecommunication. other aeronautical publications. The contraction b. II Distribution− Distribution by means other NTAP is used in NOTAM text. than telecommunications. (See NOTICE TO AIRMEN.) NOTICE TO AIRMEN (NOTAM)− A notice NRR− containing information (not known sufficiently in (See NON−RESTRICTIVE ROUTING.) advance to publicize by other means) concerning the establishment, condition, or change in any NRS− component (facility, service, or procedure of, or (See NAVIGATION REFERENCE SYSTEM.) hazard in the National Airspace System) the timely NTAP− knowledge of which is essential to personnel (See NOTICES TO AIRMEN PUBLICATION.) concerned with flight operations. NUMEROUS TARGETS VICINITY (LOCA- NOTAM(D)− A NOTAM given (in addition to local TION)− A traffic advisory issued by ATC to advise dissemination) distant dissemination beyond the area pilots that targets on the radar scope are too numerous of responsibility of the Flight Service Station. These to issue individually. NOTAMs will be stored and available until canceled. (See TRAFFIC ADVISORIES.)

PCG N−4 2/28/193/29/18 Pilot/Controller Glossary U

UHF− UNMANNED AIRCRAFT (UA)- A device used or (See ULTRAHIGH FREQUENCY.) intended to be used for flight that has no onboard pilot. This device can be any type of airplane, ULTRAHIGH FREQUENCY (UHF)− The frequen- helicopter, airship, or powered-lift aircraft. cy band between 300 and 3,000 MHz. The bank of Unmanned free balloons, moored balloons, tethered radio frequencies used for military air/ground voice aircraft, gliders, and unmanned rockets are not communications. In some instances this may go as considered to be a UA. low as 225 MHz and still be referred to as UHF. ULTRALIGHT VEHICLE− A single-occupant UNMANNED AIRCRAFT SYSTEM (UAS)- An aeronautical vehicle operated for sport or recreational unmanned aircraft and its associated elements related purposes which does not require FAA registration, an to safe operations, which may include control airworthiness certificate, or pilot certification. stations (ground, ship, or air based), control links, Operation of an ultralight vehicle in certain airspace support equipment, payloads, flight termination requires authorization from ATC. systems, and launch/recovery equipment. It consists (Refer to 14 CFR Part 103.) of three elements: unmanned aircraft, control station, and data link. UNABLE− Indicates inability to comply with a specific instruction, request, or clearance. UNPUBLISHED ROUTE− A route for which no minimum altitude is published or charted for pilot UNASSOCIATED− A radar target that does not use. It may include a direct route between NAVAIDs, display a data block with flight identification and a radial, a radar vector, or a final approach course altitude information. beyond the segments of an instrument approach (See ASSOCIATED.) procedure. UNCONTROLLED AIRSPACE− Airspace in which (See PUBLISHED ROUTE.) aircraft are not subject to controlled airspace (Class (See ROUTE.) A, B, C, D, or E) separation criteria. UNRELIABLE (GPS/WAAS)− An advisory to UNDER THE HOOD− Indicates that the pilot is pilots indicating the expected level of service of the using a hood to restrict visibility outside the cockpit GPS and/or WAAS may not be available. Pilots must while simulating instrument flight. An appropriately then determine the adequacy of the signal for desired rated pilot is required in the other control seat while use. this operation is being conducted. (Refer to 14 CFR Part 91.) UPWIND LEG− UNFROZEN− The Scheduled Time of Arrival (STA) (See TRAFFIC PATTERN.) tags, which are still being rescheduled by the time based flow management (TBFM) calculations. The URGENCY− A condition of being concerned about aircraft will remain unfrozen until the time the safety and of requiring timely but not immediate corresponding estimated time of arrival (ETA) tag assistance; a potential distress condition. passes the preset freeze horizon for that aircraft’s (See ICAO term URGENCY.) stream class. At this point the automatic rescheduling will stop, and the STA becomes “frozen.” URGENCY [ICAO]− A condition concerning the safety of an aircraft or other vehicle, or of person on UNICOM− A nongovernment communication facil- board or in sight, but which does not require ity which may provide airport information at certain immediate assistance. airports. Locations and frequencies of UNICOMs are shown on aeronautical charts and publications. USAFIB− (See CHART SUPPLEMENT U.S.) (See ARMY AVIATION FLIGHT INFORMATION (Refer to AIM.) BULLETIN.)

PCG U−1