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Instrument Rating — Airplane

110 terms, selected from FAA-S-ACS-8C, ratified by the owner, CFI, on 2026-09-02. Definitions reproduced verbatim from the FAA Pilot/Controller Glossary, effective 7/9/26.

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ATC

SeeAIR TRAFFIC CONTROL

The FAA’s definition of AIR TRAFFIC CONTROL

A service operated by appropriate authority to promote the safe, orderly and expeditious flow of air traffic.

SeeICAO term AIR TRAFFIC CONTROL SERVICE

In the glossary: a

INSTRUMENT APPROACH

SeeINSTRUMENT APPROACH PROCEDURE

The FAA’s definition of INSTRUMENT APPROACH PROCEDURE

A series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing or to a point from which a landing may be made visually. It is prescribed and approved for a specific airport by competent authority.

SeeSEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

Refer to14 CFR part 91

📖Refer toAIM (opens in new tab) ↗

  1. U.S. civil standard instrument approach procedures are approved by the FAA as prescribed under 14 CFR part 97 and are available for public use.
  2. U.S. military standard instrument approach procedures are approved and published by the Department of Defense.
  3. Special instrument approach procedures are approved by the FAA for individual operators but are not published in 14 CFR part 97 for public use.

SeeICAO term INSTRUMENT APPROACH PROCEDURE

In the glossary: i

MISSED APPROACH

  1. A maneuver conducted by a pilot when an instrument approach cannot be completed to a landing. The route of flight and altitude are shown on instrument approach procedure charts. A pilot executing a missed approach prior to the Missed Approach Point (MAP) must continue along the final approach to the MAP.
  2. A term used by the pilot to inform ATC that he/she is executing the missed approach.
  3. At locations where ATC radar service is provided, the pilot should conform to radar vectors when provided by ATC in lieu of the published missed approach procedure.

SeeMISSED APPROACH POINT

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The FAA’s definition of MISSED APPROACH POINT (MAP)

A point prescribed in each instrument approach procedure at which a missed approach procedure must be executed if the required visual reference does not exist.

SeeMISSED APPROACH

SeeSEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

In the glossary: m

AIM

SeeAERONAUTICAL INFORMATION MANUAL

The FAA’s definition of AERONAUTICAL INFORMATION MANUAL (AIM)

A primary FAA publication whose purpose is to instruct airmen about operating in the National Airspace System of the U.S. It provides basic flight information, ATC Procedures and general instructional information concerning health, medical facts, factors affecting flight safety, accident and hazard reporting, and types of aeronautical charts and their use.

In the glossary: a

AIR TRAFFIC

Aircraft operating in the air or on an airport surface, exclusive of loading ramps and parking areas.

SeeICAO term AIR TRAFFIC

In the glossary: a

AIR TRAFFIC CONTROL

A service operated by appropriate authority to promote the safe, orderly and expeditious flow of air traffic.

SeeICAO term AIR TRAFFIC CONTROL SERVICE

In the glossary: a

ATD

SeeALONG-TRACK DISTANCE

The FAA’s definition of ALONG-TRACK DISTANCE (ATD)

The horizontal distance between the aircraft's current position and a fix measured by an area navigation system that is not subject to slant range errors.

In the glossary: a

MDA

SeeMINIMUM DESCENT ALTITUDE

The FAA’s definition of MINIMUM DESCENT ALTITUDE (MDA)

The lowest altitude, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle‐to‐land maneuvering in execution of a standard instrument approach procedure where no electronic glideslope is provided.

SeeNONPRECISION APPROACH PROCEDURE

In the glossary: m

CIRCLING APPROACH

SeeCIRCLE‐TO‐LAND MANEUVER

The FAA’s definition of CIRCLE‐TO‐LAND MANEUVER

TO‐LAND MANEUVER- A maneuver initiated by the pilot to align the aircraft with a runway for landing when a straight‐in landing from an instrument approach is not possible or is not desirable. At tower controlled airports, this maneuver is made only after ATC authorization has been obtained and the pilot has established required visual reference to the airport.

SeeCIRCLE TO RUNWAY

SeeLANDING MINIMUMS

📖Refer toAIM (opens in new tab) ↗

In the glossary: c

ICING

The accumulation of airframe ice.

Types of icing are:

  1. Rime Ice- Rough, milky, opaque ice formed by the instantaneous freezing of small supercooled water droplets.
  2. Clear Ice- A glossy, clear, or translucent ice formed by the relatively slow freezing of large supercooled water droplets.
  3. Mixed- A mixture of clear ice and rime ice.

Intensity of icing:

  1. Trace- Ice becomes noticeable. The rate of accumulation is slightly greater than the rate of sublimation. A representative accretion rate for reference purposes is less than ¼ inch (6 mm) per hour on the outer wing. The pilot should consider exiting the icing conditions before they become worse.
  2. Light- The rate of ice accumulation requires occasional cycling of manual deicing systems to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is ¼ inch to 1 inch (0.6 to 2.5 cm) per hour on the unprotected part of the outer wing. The pilot should consider exiting the icing condition.
  3. Moderate- The rate of ice accumulation requires frequent cycling of manual deicing systems to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is 1 to 3 inches (2.5 to 7.5 cm) per hour on the unprotected part of the outer wing. The pilot should consider exiting the icing condition as soon as possible.
  4. Severe- The rate of ice accumulation is such that ice protection systems fail to remove the accumulation of ice and ice accumulates in locations not normally prone to icing, such as areas aft of protected surfaces and any other areas identified by the manufacturer. A representative accretion rate for reference purposes is more than 3 inches (7.5 cm) per hour on the unprotected part of the outer wing. By regulation, immediate exit is required.

In the glossary: i

IFR FLIGHT

SeeIFR AIRCRAFT

The FAA’s definition of IFR AIRCRAFT

An aircraft conducting flight in accordance with instrument flight rules.

In the glossary: i

CONTINUE

When used as a control instruction should be followed by another word or words clarifying what is expected of the pilot. Example: “continue taxi,” “continue descent,” “continue inbound,” etc.

In the glossary: c

DEVIATION

  1. A departure from a current clearance, such as an off course maneuver to avoid weather or turbulence.
  2. Where specifically authorized in the CFRs and requested by the pilot, ATC may permit pilots to deviate from certain regulations.

In the glossary: d

FINAL APPROACH [ICAO]

That part of an instrument approach procedure which commences at the specified final approach fix or point, or where such a fix or point is not specified.

  1. At the end of the last procedure turn, base turn or inbound turn of a racetrack procedure, if specified; or
  2. At the point of interception of the last track specified in the approach procedure; and ends at a point in the vicinity of an aerodrome from which:
  3. A landing can be made; or
  4. A missed approach procedure is initiated.

In the glossary: f

MONITOR

(When used with communication transfer) listen on a specific frequency and stand by for instructions. Under normal circumstances do not establish communications.

In the glossary: m

RNAV

SeeAREA NAVIGATION (RNAV.)

The FAA’s definition of AREA NAVIGATION (RNAV)

A method of navigation which permits aircraft operation on any desired flight path within the coverage of ground- or space-based navigation aids or within the limits of the capability of self‐contained aids, or a combination of these.

In the glossary: r

DME

SeeDISTANCE MEASURING EQUIPMENT

The FAA’s definition of DISTANCE MEASURING EQUIPMENT (DME)

Equipment (airborne and ground) used to measure, in nautical miles, the slant range distance of an aircraft from the DME navigational aid.

SeeTACAN

SeeVORTAC

In the glossary: d

MISSED APPROACH PROCEDURE [ICAO]

The procedure to be followed if the approach cannot be continued.

In the glossary: m

ATC CLEARANCE

SeeAIR TRAFFIC CLEARANCE

The FAA’s definition of AIR TRAFFIC CLEARANCE

An authorization by air traffic control for the purpose of preventing collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace. The pilot‐in‐command of an aircraft may not deviate from the provisions of a visual flight rules (VFR) or instrument flight rules (IFR) air traffic clearance except in an emergency or unless an amended clearance has been obtained. Additionally, the pilot may request a different clearance from that which has been issued by air traffic control (ATC) if information available to the pilot makes another course of action more practicable or if aircraft equipment limitations or company procedures forbid compliance with the clearance issued. Pilots may also request clarification or amendment, as appropriate, any time a clearance is not fully understood, or considered unacceptable because of safety of flight. Controllers should, in such instances and to the extent of operational practicality and safety, honor the pilot's request. 14 CFR part 91.3(a) states: “The pilot in command of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft.” THE PILOT IS RESPONSIBLE TO REQUEST AN AMENDED CLEARANCE if ATC issues a clearance that would cause a pilot to deviate from a rule or regulation, or in the pilot's opinion, would place the aircraft in jeopardy.

SeeATC INSTRUCTIONS

SeeICAO term AIR TRAFFIC CONTROL CLEARANCE

In the glossary: a

VISIBILITY

The ability, as determined by atmospheric conditions and expressed in units of distance, to see and identify prominent unlighted objects by day and prominent lighted objects by night. Visibility is reported as statute miles, hundreds of feet or meters.

Refer to14 CFR part 91

📖Refer toAIM (opens in new tab) ↗

  1. Flight Visibility- The average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent unlighted objects may be seen and identified by day and prominent lighted objects may be seen and identified by night.
  2. Ground Visibility- Prevailing horizontal visibility near the earth's surface as reported by the United States National Weather Service or an accredited observer.
  3. Prevailing Visibility- The greatest horizontal visibility equaled or exceeded throughout at least half the horizon circle which need not necessarily be continuous.
  4. Runway Visual Range (RVR)- An instrumentally derived value, based on standard calibrations, that represents the horizontal distance a pilot will see down the runway from the approach end. It is based on the sighting of either high intensity runway lights or on the visual contrast of other targets whichever yields the greater visual range. RVR, in contrast to prevailing or runway visibility, is based on what a pilot in a moving aircraft should see looking down the runway. RVR is horizontal visual range, not slant visual range. It is based on the measurement of a transmissometer made near the touchdown point of the instrument runway and is reported in hundreds of feet. RVR, where available, is used in lieu of prevailing visibility in determining minimums for a particular runway.
  5. Touchdown RVR- The RVR visibility readout values obtained from RVR equipment serving the runway touchdown zone.
  6. Mid‐RVR- The RVR readout values obtained from RVR equipment located midfield of the runway.
  7. Rollout RVR- The RVR readout values obtained from RVR equipment located nearest the rollout end of the runway.

SeeICAO term FLIGHT VISIBILITY

SeeICAO term GROUND VISIBILITY

SeeICAO term RUNWAY VISUAL RANGE

SeeICAO term VISIBILITY

In the glossary: v

TURBULENCE

An atmospheric phenomenon that causes changes in aircraft altitude, attitude, and or airspeed with aircraft reaction depending on intensity. Pilots report turbulence intensity according to aircraft's reaction as follows:

  1. Light - Causes slight, erratic changes in altitude and or attitude (pitch, roll, or yaw).
  2. Moderate- Similar to Light but of greater intensity. Changes in altitude and or attitude occur but the aircraft remains in positive control at all times. It usually causes variations in indicated airspeed.
  3. Severe- Causes large, abrupt changes in altitude and or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control.
  4. Extreme- The aircraft is violently tossed about and is practically impossible to control. It may cause structural damage.

SeeCHOP

📖Refer toAIM (opens in new tab) ↗

In the glossary: t

UNABLE

Indicates inability to comply with a specific instruction, request, or clearance.

In the glossary: u

AIRCRAFT APPROACH CATEGORY

A grouping of aircraft based on a speed of 1.3 times the stall speed in the landing configuration at maximum gross landing weight. An aircraft must fit in only one category. If it is necessary to maneuver at speeds in excess of the upper limit of a speed range for a category, the minimums for the category for that speed must be used. For example, an aircraft which falls in Category A, but is circling to land at a speed in excess of 91 knots, must use the approach Category B minimums when circling to land. The categories are as follows:

  1. Category A- Speed less than 91 knots.
  2. Category B- Speed 91 knots or more but less than 121 knots.
  3. Category C- Speed 121 knots or more but less than 141 knots.
  4. Category D- Speed 141 knots or more but less than 166 knots.
  5. Category E- Speed 166 knots or more.

Refer to14 CFR part 97

In the glossary: a

AREA NAVIGATION (RNAV)

A method of navigation which permits aircraft operation on any desired flight path within the coverage of ground- or space-based navigation aids or within the limits of the capability of self‐contained aids, or a combination of these.

In the glossary: a

BEARING

The horizontal direction to or from any point, usually measured clockwise from true north, magnetic north, or some other reference point through 360 degrees.

SeeNONDIRECTIONAL BEACON

In the glossary: b

DECISION ALTITUDE (DA)

A specified altitude (mean sea level (MSL)) on an instrument approach procedure (ILS, GLS, vertically guided RNAV) at which the pilot must decide whether to continue the approach or initiate an immediate missed approach if the pilot does not see the required visual references.

In the glossary: d

ELIGIBILITY

Designates which sector is eligible to exchange CPDLC messages with a specific aircraft.

In the glossary: e

ESTABLISHED

To be stable or fixed at an altitude or on a course, route, route segment, heading, instrument approach or departure procedure, etc.

In the glossary: e

FMS

SeeFLIGHT MANAGEMENT SYSTEM

The FAA’s definition of FLIGHT MANAGEMENT SYSTEMS

A computer system that uses a large data base to allow routes to be preprogrammed and fed into the system by means of a data loader. The system is constantly updated with respect to position accuracy by reference to conventional navigation aids. The sophisticated program and its associated data base ensures that the most appropriate aids are automatically selected during the information update cycle.

In the glossary: f

IMMEDIATELY

Used by ATC or pilots when such action compliance is required to avoid an imminent situation.

In the glossary: i

MINIMUM DESCENT ALTITUDE (MDA)

The lowest altitude, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle‐to‐land maneuvering in execution of a standard instrument approach procedure where no electronic glideslope is provided.

SeeNONPRECISION APPROACH PROCEDURE

In the glossary: m

VFR

SeeVISUAL FLIGHT RULES

The FAA’s definition of VISUAL FLIGHT RULES

Rules that govern the procedures for conducting flight under visual conditions. The term “VFR” is also used in the United States to indicate weather conditions that are equal to or greater than minimum VFR requirements. In addition, it is used by pilots and controllers to indicate type of flight plan.

SeeINSTRUMENT FLIGHT RULES

SeeINSTRUMENT METEOROLOGICAL CONDITIONS

SeeVISUAL METEOROLOGICAL CONDITIONS

Refer to14 CFR part 91

📖Refer toAIM (opens in new tab) ↗

In the glossary: v

ALTERNATE AIRPORT

An airport at which an aircraft may land if a landing at the intended airport becomes inadvisable.

SeeICAO term ALTERNATE AERODROME

In the glossary: a

ARC

The track over the ground of an aircraft flying at a constant distance from a navigational aid by reference to distance measuring equipment (DME).

In the glossary: a

ATC INSTRUCTIONS

Directives issued by air traffic control for the purpose of requiring a pilot to take specific actions; e.g., “Turn left heading two five zero,” “Go around,” “Clear the runway.”

Refer to14 CFR part 91

In the glossary: a

DECISION HEIGHT (DH)

With respect to the operation of aircraft, means the height at which a decision must be made during an ILS or PAR instrument approach to either continue the approach or to execute a missed approach.

SeeICAO term DECISION ALTITUDE/DECISION HEIGHT

In the glossary: d

DISTANCE MEASURING EQUIPMENT (DME)

Equipment (airborne and ground) used to measure, in nautical miles, the slant range distance of an aircraft from the DME navigational aid.

SeeTACAN

SeeVORTAC

In the glossary: d

FINAL APPROACH SEGMENT

SeeSEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

The FAA’s definition of SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

An instrument approach procedure may have as many as four separate segments depending on how the approach procedure is structured.

  1. Initial Approach- The segment between the initial approach fix and the intermediate fix or the point where the aircraft is established on the intermediate course or final approach course.

SeeICAO term INITIAL APPROACH SEGMENT

  1. Intermediate Approach- The segment between the intermediate fix or point and the final approach fix.

SeeICAO term INTERMEDIATE APPROACH SEGMENT

  1. Final Approach- The segment between the final approach fix or point and the runway, airport, or missed approach point.

SeeICAO term FINAL APPROACH SEGMENT

  1. Missed Approach- The segment between the missed approach point or the point of arrival at decision height and the missed approach fix at the prescribed altitude.

Refer to14 CFR part 97

SeeICAO term MISSED APPROACH PROCEDURE

In the glossary: f

INSTRUMENT APPROACH PROCEDURE

A series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing or to a point from which a landing may be made visually. It is prescribed and approved for a specific airport by competent authority.

SeeSEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

Refer to14 CFR part 91

📖Refer toAIM (opens in new tab) ↗

  1. U.S. civil standard instrument approach procedures are approved by the FAA as prescribed under 14 CFR part 97 and are available for public use.
  2. U.S. military standard instrument approach procedures are approved and published by the Department of Defense.
  3. Special instrument approach procedures are approved by the FAA for individual operators but are not published in 14 CFR part 97 for public use.

SeeICAO term INSTRUMENT APPROACH PROCEDURE

In the glossary: i

INTEGRITY

The ability of a system to provide timely warnings to users when the system should not be used for navigation.

In the glossary: i

RADAR

A device that provides information on range, azimuth, and/or elevation of objects by measuring the time interval between transmission and reception of directional radio pulses and correlating the angular orientation of the radiated antenna beam or beams in azimuth and/or elevation.

  1. Primary Radar- A radar system in which a minute portion of a radio pulse transmitted from a site is reflected by an object and then received back at that site for processing and display at an air traffic control facility.
  2. Secondary Radar/Radar Beacon (ATCRBS)- A radar system in which the object to be detected is fitted with cooperative equipment in the form of a radio receiver/transmitter (transponder). Radar pulses transmitted from the searching transmitter/receiver (interrogator) site are received in the cooperative equipment and used to trigger a distinctive transmission from the transponder. This reply transmission, rather than a reflected signal, is then received back at the transmitter/receiver site for processing and display at an air traffic control facility.

SeeCOOPERATIVE SURVEILLANCE

SeeINTERROGATOR

SeeNON-COOPERATIVE SURVEILLANCE

SeeTRANSPONDER

SeeICAO term RADAR

📖Refer toAIM (opens in new tab) ↗

In the glossary: r

RADIAL

A magnetic bearing extending from a VOR/VORTAC/TACAN navigation facility.

In the glossary: r

SEE AND AVOID

When weather conditions permit, pilots operating IFR or VFR are required to observe and maneuver to avoid other aircraft. Right‐of‐way rules are contained in 14 CFR part 91.

In the glossary: s

SIGMET

A weather advisory issued concerning weather significant to the safety of all aircraft. SIGMET advisories cover severe and extreme turbulence, severe icing, and widespread dust or sandstorms that reduce visibility to less than 3 miles.

SeeAIRMET

SeeCONVECTIVE SIGMET

SeeCWA

SeeGRAPHICAL AIRMEN'S METEOROLOGICAL INFORMATION

SeeICAO term SIGMET INFORMATION

SeeSAW

📖Refer toAIM (opens in new tab) ↗

In the glossary: s

STANDARD INSTRUMENT APPROACH PROCEDURE (SIAP)

SeeINSTRUMENT APPROACH PROCEDURE

The FAA’s definition of INSTRUMENT APPROACH PROCEDURE

A series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing or to a point from which a landing may be made visually. It is prescribed and approved for a specific airport by competent authority.

SeeSEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

Refer to14 CFR part 91

📖Refer toAIM (opens in new tab) ↗

  1. U.S. civil standard instrument approach procedures are approved by the FAA as prescribed under 14 CFR part 97 and are available for public use.
  2. U.S. military standard instrument approach procedures are approved and published by the Department of Defense.
  3. Special instrument approach procedures are approved by the FAA for individual operators but are not published in 14 CFR part 97 for public use.

SeeICAO term INSTRUMENT APPROACH PROCEDURE

In the glossary: s

TRANSITION

The general term that describes the change from one phase of flight or flight condition to another; e.g., transition from en route flight to the approach or transition from instrument flight to visual flight.

In the glossary: t

TRANSPONDER

The airborne radar beacon receiver/transmitter portion of the Air Traffic Control Radar Beacon System (ATCRBS) which automatically receives radio signals from interrogators on the ground, and selectively replies with a specific reply pulse or pulse group only to those interrogations being received on the mode to which it is set to respond.

SeeINTERROGATOR

SeeICAO term TRANSPONDER

📖Refer toAIM (opens in new tab) ↗

In the glossary: t

VDP

SeeVISUAL DESCENT POINT

The FAA’s definition of VISUAL DESCENT POINT

A defined point on the final approach course of a nonprecision straight‐in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided the approach threshold of that runway, or approach lights, or other markings identifiable with the approach end of that runway are clearly visible to the pilot.

In the glossary: v

VISUAL DESCENT POINT

A defined point on the final approach course of a nonprecision straight‐in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided the approach threshold of that runway, or approach lights, or other markings identifiable with the approach end of that runway are clearly visible to the pilot.

In the glossary: v

WAAS

SeeWIDE‐AREA AUGMENTATION SYSTEM

The FAA’s definition of WIDE‐AREA AUGMENTATION SYSTEM (WAAS)

AREA AUGMENTATION SYSTEM (WAAS)- The WAAS is a satellite navigation system consisting of the equipment and software which augments the GPS Standard Positioning Service (SPS). The WAAS provides enhanced integrity, accuracy, availability, and continuity over and above GPS SPS. The differential correction function provides improved accuracy required for precision approach.

In the glossary: w

WAYPOINT

A predetermined geographical position used for route/instrument approach definition, progress reports, published VFR routes, visual reporting points or points for transitioning and/or circumnavigating controlled and/or special use airspace, that is defined relative to a VORTAC station or in terms of latitude/longitude coordinates.

In the glossary: w

ADMINISTRATOR

The Federal Aviation Administrator or any person to whom he/she has delegated his/her authority in the matter concerned.

In the glossary: a

ADS [ICAO]

SeeICAO term AUTOMATIC DEPENDENT SURVEILLANCE

The FAA’s definition of AUTOMATIC DEPENDENT SURVEILLANCE (ADS) [ICAO]

A surveillance technique in which aircraft automatically provide, via a data link, data derived from on-board navigation and position fixing systems, including aircraft identification, four dimensional position and additional data as appropriate.

In the glossary: a

ADVISORY CIRCULAR (AC)

An FAA publication, advisory and descriptive in nature, which is not regulatory.

In the glossary: a

AERODROME

A defined area on land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure, and movement of aircraft.

In the glossary: a

AERONAUTICAL INFORMATION MANUAL (AIM)

A primary FAA publication whose purpose is to instruct airmen about operating in the National Airspace System of the U.S. It provides basic flight information, ATC Procedures and general instructional information concerning health, medical facts, factors affecting flight safety, accident and hazard reporting, and types of aeronautical charts and their use.

In the glossary: a

AIRBORNE

An aircraft is considered airborne when all parts of the aircraft are off the ground.

In the glossary: a

AIRMEN'S METEOROLOGICAL INFORMATION (AIRMET)

A concise description of an occurrence or expected occurrence of specified en route weather phenomena that may affect the safety of aircraft operations, but at intensities lower than those that require the issuance of a SIGMET. An AIRMET may be issued when any of the following weather phenomena are occurring or expected to occur:

  1. Moderate turbulence
  2. Low-level windshear
  3. Strong surface winds greater than 30 knots
  4. Moderate icing
  5. Freezing level
  6. Mountain obscuration
  7. IFR

SeeCONVECTIVE SIGMET

SeeCWA

SeeGRAPHICAL AIRMEN'S METEOROLOGICAL INFORMATION

SeeSAW

SeeSIGMET

📖Refer toAIM (opens in new tab) ↗

In the glossary: a

ALERT

A notification to a position that there is an aircraft‐to‐aircraft or aircraft‐to‐airspace conflict, as detected by Automated Problem Detection (APD).

In the glossary: a

AUTOMATIC DEPENDENT SURVEILLANCE

BROADCAST (ADS‐B)- A surveillance system in which an aircraft or vehicle to be detected is fitted with cooperative equipment in the form of a data link transmitter. The aircraft or vehicle periodically broadcasts its GNSS-derived position and other required information such as identity and velocity, which is then received by a ground-based or space-based receiver for processing and display at an air traffic control facility, as well as by suitably equipped aircraft.

SeeAUTOMATIC DEPENDENT SURVEILLANCE-BROADCAST IN

SeeAUTOMATIC DEPENDENT SURVEILLANCE-BROADCAST OUT

SeeCOOPERATIVE SURVEILLANCE

SeeGLOBAL POSITIONING SYSTEM

SeeSPACE-BASED ADS-B

In the glossary: a

BEACON

SeeAERONAUTICAL BEACON

SeeAIRPORT ROTATING BEACON

SeeAIRWAY BEACON

SeeMARKER BEACON

SeeNONDIRECTIONAL BEACON

SeeRADAR

The FAA’s definition of AERONAUTICAL BEACON

A visual NAVAID displaying flashes of white and/or colored light to indicate the location of an airport, a heliport, a landmark, a certain point of a Federal airway in mountainous terrain, or an obstruction.

SeeAIRPORT ROTATING BEACON

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The FAA’s definition of AIRPORT ROTATING BEACON

A visual NAVAID operated at many airports. At civil airports, alternating white and green flashes indicate the location of the airport. At military airports, the beacons flash alternately white and green, but are differentiated from civil beacons by dualpeaked (two quick) white flashes between the green flashes.

SeeINSTRUMENT FLIGHT RULES

SeeSPECIAL VFR OPERATIONS

SeeICAO term AERODROME BEACON

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The FAA’s definition of AIRWAY BEACON

Used to mark airway segments in remote mountain areas. The light flashes Morse Code to identify the beacon site.

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In the glossary: b

BROADCAST

Transmission of information for which an acknowledgement is not expected.

SeeICAO term BROADCAST

In the glossary: b

CEILING

The heights above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as “broken,” “overcast,” or “obscuration,” and not classified as “thin” or “partial.”

SeeICAO term CEILING

In the glossary: c

CLEARANCE LIMIT

The fix, point, or location to which an aircraft is cleared when issued an air traffic clearance.

SeeICAO term CLEARANCE LIMIT

In the glossary: c

CONVECTIVE SIGMET

A weather advisory concerning convective weather significant to the safety of all aircraft. Convective SIGMETs are issued for tornadoes, lines of thunderstorms, embedded thunderstorms of any intensity level, areas of thunderstorms greater than or equal to VIP level 4 with an area coverage of 4/10 (40%) or more, and hail 3/4 inch or greater.

SeeAIRMET

SeeCWA

SeeGRAPHICAL AIRMEN'S METEOROLOGICAL INFORMATION

SeeSAW

SeeSIGMET

📖Refer toAIM (opens in new tab) ↗

In the glossary: c

CRUISE

Used in an ATC clearance to authorize a pilot to conduct flight at any altitude from the minimum IFR altitude up to and including the altitude specified in the clearance. The pilot may level off at any intermediate altitude within this block of airspace. Climb/descent within the block is to be made at the discretion of the pilot. However, once the pilot starts descent and verbally reports leaving an altitude in the block, he/she may not return to that altitude without additional ATC clearance. Further, it is approval for the pilot to proceed to and make an approach at destination airport and can be used in conjunction with:

  1. An airport clearance limit at locations with a standard/special instrument approach procedure. The CFRs require that if an instrument letdown to an airport is necessary, the pilot must make the letdown in accordance with a standard/special instrument approach procedure for that airport, or
  2. An airport clearance limit at locations that are within/below/outside controlled airspace and without a standard/special instrument approach procedure. Such a clearance is NOT AUTHORIZATION for the pilot to descend under IFR conditions below the applicable minimum IFR altitude nor does it imply that ATC is exercising control over aircraft in Class G airspace; however, it provides a means for the aircraft to proceed to destination airport, descend, and land in accordance with applicable CFRs governing VFR flight operations. Also, this provides search and rescue protection until such time as the IFR flight plan is closed.

SeeINSTRUMENT APPROACH PROCEDURE

In the glossary: c

DIVERSION (DVRSN)

Flights that are required to land at other than their original destination for reasons beyond the control of the pilot/company, e.g. periods of significant weather.

In the glossary: d

DOWNWIND LEG

SeeTRAFFIC PATTERN

The FAA’s definition of TRAFFIC PATTERN

The traffic flow that is prescribed for aircraft landing at, taxiing on, or taking off from an airport. The components of a typical traffic pattern are departure, upwind leg, crosswind leg, downwind leg, base leg, and final approach.

  1. Upwind Leg- A flight path that begins after departure and continues straight ahead along the extended runway centerline. Upwind leg is an extension of departure and is used when issuing control instructions for separation, spacing or sequencing.
  2. Crosswind Leg- A flight path at right angles to the landing runway off its upwind end.
  3. Downwind Leg- A flight path parallel to the landing runway in the direction opposite to landing. The downwind leg normally extends between the crosswind leg and the base leg.
  4. Base Leg- A flight path at right angles to the landing runway off its approach end. The base leg normally extends from the downwind leg to the intersection of the extended runway centerline.

NOTE-
ATC may instruct a pilot to report a “2‐mile left base” to Runway 22. This instruction means that the pilot is expected to maneuver their aircraft into a left base leg that will intercept a straight‐in final 2 miles from the approach end of Runway 22 and advise ATC.

REFERENCE-
Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25, Chapter 14, Airport Operations, Traffic Patterns.

  1. Final Approach- A flight path in the direction of landing along the extended runway centerline. The final approach normally extends from the base leg to the runway. An aircraft making a straight‐in approach VFR is also considered to be on final approach.

NOTE-
ATC may instruct a pilot to report “5‐mile final” to Runway 22. This instruction means that the pilot should maneuver their aircraft onto a straight‐in final and advise ATC when they are five miles from the approach end of Runway 22.

  1. Departure- The flight path that begins after takeoff and continues straight ahead along the extended runway centerline. The departure climb continues until reaching a point at least 1/2 mile beyond the departure end of the runway and within 300 feet of the traffic pattern altitude.

REFERENCE-
Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25, Chapter 14, Airport Operations, Traffic Patterns.

SeeSTRAIGHT‐IN APPROACH VFR

SeeTAXI PATTERNS

SeeICAO term AERODROME TRAFFIC CIRCUIT

Refer to14 CFR part 91

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In the glossary: d

ESTIMATED (EST)

When used in NOTAMs “EST” is a contraction that is used by the issuing authority only when the condition is expected to return to service prior to the expiration time. Using “EST” lets the user know that this NOTAM has the possibility of returning to service earlier than the expiration time. Any NOTAM which includes an “EST” will be auto-expired at the designated expiration time.

In the glossary: e

ESTIMATED TIME OF ARRIVAL

The time the flight is estimated to arrive at the gate (scheduled operators) or the actual runway on times for nonscheduled operators.

In the glossary: e

EXPECT FURTHER CLEARANCE (TIME)

The time a pilot can expect to receive clearance beyond a clearance limit.

In the glossary: e

FAF

SeeFINAL APPROACH FIX

The FAA’s definition of FINAL APPROACH FIX

The fix from which the final approach (IFR) to an airport is executed and which identifies the beginning of the final approach segment. It is designated on Government charts by the Maltese Cross symbol for nonprecision approaches and the lightning bolt symbol, designating the PFAF, for precision approaches; or when ATC directs a lower‐than‐published glideslope/path or vertical path intercept altitude, it is the resultant actual point of the glideslope/path or vertical path intercept.

SeeFINAL APPROACH POINT

SeeGLIDESLOPE INTERCEPT ALTITUDE

SeeSEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

In the glossary: f

FINAL APPROACH FIX

The fix from which the final approach (IFR) to an airport is executed and which identifies the beginning of the final approach segment. It is designated on Government charts by the Maltese Cross symbol for nonprecision approaches and the lightning bolt symbol, designating the PFAF, for precision approaches; or when ATC directs a lower‐than‐published glideslope/path or vertical path intercept altitude, it is the resultant actual point of the glideslope/path or vertical path intercept.

SeeFINAL APPROACH POINT

SeeGLIDESLOPE INTERCEPT ALTITUDE

SeeSEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE

In the glossary: f

GENERAL AVIATION

That portion of civil aviation that does not include scheduled or unscheduled air carriers or commercial space operations.

SeeICAO term GENERAL AVIATION

In the glossary: g

GLIDEPATH

SeeGLIDESLOPE

The FAA’s definition of GLIDESLOPE

Provides vertical guidance for aircraft during approach and landing. The glideslope/glidepath is based on the following:

  1. Electronic components emitting signals which provide vertical guidance by reference to airborne instruments during instrument approaches such as ILS; or,
  2. Visual ground aids, such as VASI, which provide vertical guidance for a VFR approach or for the visual portion of an instrument approach and landing.
  3. Used by ATC to inform an aircraft making a PAR approach of its vertical position (elevation) relative to the descent profile.

SeeICAO term GLIDEPATH

In the glossary: g

GLOBAL POSITIONING SYSTEM (GPS)

GPS refers to the worldwide positioning, navigation and timing determination capability available from the U.S. satellite constellation. The service provided by GPS for civil use is defined in the GPS Standard Positioning System Performance Standard. GPS is composed of space, control, and user elements.

In the glossary: g

GPS

SeeGLOBAL POSITIONING SYSTEM

The FAA’s definition of GLOBAL POSITIONING SYSTEM (GPS)

GPS refers to the worldwide positioning, navigation and timing determination capability available from the U.S. satellite constellation. The service provided by GPS for civil use is defined in the GPS Standard Positioning System Performance Standard. GPS is composed of space, control, and user elements.

In the glossary: g

IDENTIFICATION [ICAO]

The situation which exists when the position indication of a particular aircraft is seen on a situation display and positively identified.

In the glossary: i

LATERAL NAVIGATION (LNAV)

A function of area navigation (RNAV) equipment which calculates, displays, and provides lateral guidance to a profile or path.

In the glossary: l

LOST COMMUNICATIONS

Loss of the ability to communicate by radio. Aircraft are sometimes referred to as NORDO (No Radio). Standard pilot procedures are specified in 14 CFR part 91. Radar controllers issue procedures for pilots to follow in the event of lost communications during a radar approach when weather reports indicate that an aircraft will likely encounter IFR weather conditions during the approach.

Refer to14 CFR part 91

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In the glossary: l

MARKER BEACON

An electronic navigation facility transmitting a 75 MHz vertical fan or boneshaped radiation pattern. Marker beacons are identified by their modulation frequency and keying code, and when received by compatible airborne equipment, indicate to the pilot, both aurally and visually, that he/she is passing over the facility.

SeeINNER MARKER

SeeMIDDLE MARKER

SeeOUTER MARKER

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In the glossary: m

MINIMUM FUEL

Indicates that an aircraft's fuel supply has reached a state where, upon reaching the destination, it can accept little or no delay. This is not an emergency situation but merely indicates an emergency situation is possible should any undue delay occur.

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In the glossary: m

MODE

The letter or number assigned to a specific pulse spacing of radio signals transmitted or received by ground interrogator or airborne transponder components of the Air Traffic Control Radar Beacon System (ATCRBS). Mode A (military Mode 3) and Mode C (altitude reporting) are used in air traffic control.

SeeINTERROGATOR

SeeRADAR

SeeTRANSPONDER

SeeICAO term MODE

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In the glossary: m

MOUNTAIN WAVE

Mountain waves occur when air is being blown over a mountain range or even the ridge of a sharp bluff area. As the air hits the upwind side of the range, it starts to climb, thus creating what is generally a smooth updraft which turns into a turbulent downdraft as the air passes the crest of the ridge. Mountain waves can cause significant fluctuations in airspeed and altitude with or without associated turbulence.

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In the glossary: m

NAS

SeeNATIONAL AIRSPACE SYSTEM

The FAA’s definition of NATIONAL AIRSPACE SYSTEM

The common network of U.S. airspace; air navigation facilities, equipment and services, airports or landing areas; aeronautical charts, information and services; rules, regulations and procedures, technical information, and manpower and material. Included are system components shared jointly with the military.

In the glossary: n

NATIONAL AIRSPACE SYSTEM

The common network of U.S. airspace; air navigation facilities, equipment and services, airports or landing areas; aeronautical charts, information and services; rules, regulations and procedures, technical information, and manpower and material. Included are system components shared jointly with the military.

In the glossary: n

PRECIPITATION

Any or all forms of water particles (rain, sleet, hail, or snow) that fall from the atmosphere and reach the surface.

In the glossary: p

Source. Definitions: FAA Pilot/Controller Glossary, effective 7/9/26, reproduced verbatim from https://www.faa.gov/Air_traffic/publications/atpubs/pcg_html/index.html. A United States Government work. Selection: terms used in FAA-S-ACS-8C, cut to this list by a CFI (keep 110 of 110; cut: none). Check the current publication before you rely on any of it.