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A-Z Aviation Terms

Abeam (frequently used)

An aircraft is “abeam” a fix, point, or object when that fix, point, or object is approximately 90 degrees to the right or left of the aircraft track. Abeam indicates a general position rather than a precise point.
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Abort (frequently used)

To terminate a preplanned aircraft maneuver; e.g., an aborted takeoff.
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Acknowledge (frequently used)

Let me know that you have received and understood this message.
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Additional Services

Advisory information provided by ATC which includes but is not limited to the following:
  1. Traffic advisories.
  2. Vectors, when requested by the pilot, to assist aircraft receiving traffic advisories to avoid observed traffic.
  3. Altitude deviation information of 300 feet or more from an assigned altitude as observed on a verified (reading correctly) automatic altitude readout (Mode C).
  4. Advisories that traffic is no longer a factor.
  5. Weather and chaff information.
  6. Weather assistance.
  7. Bird activity information.
  8. Holding pattern surveillance. Additional services are provided to the extent possible contingent only upon the controller's capability to fit them into the performance of higher priority duties and on the basis of limitations of the radar, volume of traffic, frequency congestion, and controller workload. The controller has complete discretion for determining if he/she is able to provide or continue to provide a service in a particular case. The controller's reason not to provide or continue to provide a service in a particular case is not subject to question by the pilot and need not be made known to him/her.
See TRAFFIC ADVISORIES Refer to AIM
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Aerodrome Traffic Circuit [ICAO]

The specified path to be flown by aircraft operating in the vicinity of an aerodrome.
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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.
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AIM

See AERONAUTICAL INFORMATION MANUAL
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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. See ATC INSTRUCTIONS See ICAO term AIR TRAFFIC CONTROL CLEARANCE
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Air Traffic Control Clearance [ICAO]

Authorization for an aircraft to proceed under conditions specified by an air traffic control unit. Note 1: For convenience, the term air traffic control clearance is frequently abbreviated to clearance when used in appropriate contexts. Note 2: The abbreviated term clearance may be prefixed by the words taxi, takeoff, departure, en route, approach or landing to indicate the particular portion of flight to which the air traffic control clearance relates.
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Aircraft Classes

For the purposes of Wake Turbulence Separation Minima, ATC classifies aircraft as Heavy, Large, and Small as follows:
  1. Heavy- Aircraft capable of takeoff weights of 300,000 pounds or more whether or not they are operating at this weight during a particular phase of flight.
  2. Large- Aircraft of more than 41,000 pounds, maximum certificated takeoff weight, up to but not including 300,000 pounds.
  3. Small- Aircraft of 41,000 pounds or less maximum certificated takeoff weight.
Refer to AIM
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AIRMET (frequently used)

In‐flight weather advisories issued only to amend the area forecast concerning weather phenomena which are of operational interest to all aircraft and potentially hazardous to aircraft having limited capability because of lack of equipment, instrumentation, or pilot qualifications. AIRMETs concern weather of less severity than that covered by SIGMETs or Convective SIGMETs. AIRMETs cover moderate icing, moderate turbulence, sustained winds of 30 knots or more at the surface, widespread areas of ceilings less than 1,000 feet and/or visibility less than 3 miles, and extensive mountain obscurement. See AWW See CONVECTIVE SIGMET See CWA See SIGMET Refer to AIM
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Airport Lighting

Various lighting aids that may be installed on an airport. Types of airport lighting include:
  1. Approach Light System (ALS)- An airport lighting facility which provides visual guidance to landing aircraft by radiating light beams in a directional pattern by which the pilot aligns the aircraft with the extended centerline of the runway on his/her final approach for landing. Condenser‐Discharge Sequential Flashing Lights/Sequenced Flashing Lights may be installed in conjunction with the ALS at some airports. Types of Approach Light Systems are:
    1. ALSF‐1- Approach Light System with Sequenced Flashing Lights in ILS Cat‐I configuration.
    2. ALSF‐2- Approach Light System with Sequenced Flashing Lights in ILS Cat‐II configuration. The ALSF‐2 may operate as an SSALR when weather conditions permit.
    3. SSALF- Simplified Short Approach Light System with Sequenced Flashing Lights.
    4. SSALR- Simplified Short Approach Light System with Runway Alignment Indicator Lights.
    5. MALSF- Medium Intensity Approach Light System with Sequenced Flashing Lights.
    6. MALSR- Medium Intensity Approach Light System with Runway Alignment Indicator Lights.
    7. RLLS- Runway Lead‐in Light System Consists of one or more series of flashing lights installed at or near ground level that provides positive visual guidance along an approach path, either curving or straight, where special problems exist with hazardous terrain, obstructions, or noise abatement procedures.
    8. RAIL- Runway Alignment Indicator Lights- Sequenced Flashing Lights which are installed only in combination with other light systems.
    9. ODALS- Omnidirectional Approach Lighting System consists of seven omnidirectional flashing lights located in the approach area of a nonprecision runway. Five lights are located on the runway centerline extended with the first light located 300 feet from the threshold and extending at equal intervals up to 1,500 feet from the threshold. The other two lights are located, one on each side of the runway threshold, at a lateral distance of 40 feet from the runway edge, or 75 feet from the runway edge when installed on a runway equipped with a VASI.
    (Refer to FAAO JO 6850.2, VISUAL GUIDANCE LIGHTING SYSTEMS.)
  2. Runway Lights/Runway Edge Lights- Lights having a prescribed angle of emission used to define the lateral limits of a runway. Runway lights are uniformly spaced at intervals of approximately 200 feet, and the intensity may be controlled or preset.
  3. Touchdown Zone Lighting- Two rows of transverse light bars located symmetrically about the runway centerline normally at 100 foot intervals. The basic system extends 3,000 feet along the runway.
  4. Runway Centerline Lighting- Flush centerline lights spaced at 50‐foot intervals beginning 75 feet from the landing threshold and extending to within 75 feet of the opposite end of the runway.
  5. Threshold Lights- Fixed green lights arranged symmetrically left and right of the runway centerline, identifying the runway threshold.
  6. Runway End Identifier Lights (REIL)- Two synchronized flashing lights, one on each side of the runway threshold, which provide rapid and positive identification of the approach end of a particular runway.
  7. Visual Approach Slope Indicator (VASI)- An airport lighting facility providing vertical visual approach slope guidance to aircraft during approach to landing by radiating a directional pattern of high intensity red and white focused light beams which indicate to the pilot that he/she is “on path” if he/she sees red/white, “above path” if white/white, and “below path” if red/red. Some airports serving large aircraft have three‐bar VASIs which provide two visual glide paths to the same runway.
  8. Precision Approach Path Indicator (PAPI)- An airport lighting facility, similar to VASI, providing vertical approach slope guidance to aircraft during approach to landing. PAPIs consist of a single row of either two or four lights, normally installed on the left side of the runway, and have an effective visual range of about 5 miles during the day and up to 20 miles at night. PAPIs radiate a directional pattern of high intensity red and white focused light beams which indicate that the pilot is “on path” if the pilot sees an equal number of white lights and red lights, with white to the left of the red; “above path” if the pilot sees more white than red lights; and “below path” if the pilot sees more red than white lights.
  9. Boundary Lights- Lights defining the perimeter of an airport or landing area.
Refer to AIM
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Alphanumeric Display

Letters and numerals used to show identification, altitude, beacon code, and other information concerning a target on a radar display. See AUTOMATED RADAR TERMINAL SYSTEMS
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Altitude Readout (frequently used)

An aircraft's altitude, transmitted via the Mode C transponder feature, that is visually displayed in 100‐foot increments on a radar scope having readout capability. See ALPHANUMERIC DISPLAY See AUTOMATED RADAR TERMINAL SYSTEMS Refer to AIM
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Altitude Restriction

An altitude or altitudes, stated in the order flown, which are to be maintained until reaching a specific point or time. Altitude restrictions may be issued by ATC due to traffic, terrain, or other airspace considerations.
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Altitude Restrictions Are Canceled (frequently used)

Adherence to previously imposed altitude restrictions is no longer required during a climb or descent.
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Approach Clearance

Authorization by ATC for a pilot to conduct an instrument approach. The type of instrument approach for which a clearance and other pertinent information is provided in the approach clearance when required. See CLEARED APPROACH See INSTRUMENT APPROACH PROCEDURE Refer to AIM Refer to 14 CFR Part 91
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Approach Speed (frequently used)

The recommended speed contained in aircraft manuals used by pilots when making an approach to landing. This speed will vary for different segments of an approach as well as for aircraft weight and configuration.
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Appropriate Obstacle Clearance Minimum Altitude (frequently used)

Any of the following:
  • Minimum En Route IFR Altitude
  • Minimum IFR Altitude
  • Minimum Obstruction Clearance Altitude
  • Minimum Vectoring Altitude

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Appropriate Terrain Clearance Minimum Altitude (frequently used)

Any of the following:
  • Minimum En Route IFR Altitude
  • Minimum IFR Altitude
  • Minimum Obstruction Clearance Altitude
  • Minimum Vectoring Altitude

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Associated

A radar target displaying a data block with flight identification and altitude information. See UNASSOCIATED
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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 to 14 CFR Part 91
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Automated Radar Terminal Systems (ARTS)

A generic term for several tracking systems included in the Terminal Automation Systems (TAS). ARTS plus a suffix roman numeral denotes a major modification to that system.
  1. ARTS IIIA. The Radar Tracking and Beacon Tracking Level (RT&BTL) of the modular, programmable automated radar terminal system. ARTS IIIA detects, tracks, and predicts primary as well as secondary radar‐derived aircraft targets. This more sophisticated computer‐driven system upgrades the existing ARTS III system by providing improved tracking, continuous data recording, and fail‐soft capabilities.
  2. Common ARTS. Includes ARTS IIE, ARTS IIIE; and ARTS IIIE with ACD (see DTAS) which combines functionalities of the previous ARTS systems.
  3. Programmable Indicator Data Processor (PIDP). The PIDP is a modification to the AN/TPX-42 interrogator system currently installed in fixed RAPCONs. The PIDP detects, tracks, and predicts secondary radar aircraft targets. These are displayed by means of computer-generated symbols and alphanumeric characters depicting flight identification, aircraft altitude, ground speed, and flight plan data. Although primary radar targets are not tracked, they are displayed coincident with the secondary radar targets as well as with the other symbols and alphanumerics. The system has the capability of interfacing with ARTCCs.

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Automatic Direction Finder

An aircraft radio navigation system which senses and indicates the direction to a L/MF nondirectional radio beacon (NDB) ground transmitter. Direction is indicated to the pilot as a magnetic bearing or as a relative bearing to the longitudinal axis of the aircraft depending on the type of indicator installed in the aircraft. In certain applications, such as military, ADF operations may be based on airborne and ground transmitters in the VHF/UHF frequency spectrum. See BEARING See NONDIRECTIONAL BEACON
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AWW

See SEVERE WEATHER FORECAST ALERTS
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Back-Taxi (frequently used)

A term used by air traffic controllers to taxi an aircraft on the runway opposite to the traffic flow. The aircraft may be instructed to back-taxi to the beginning of the runway or at some point before reaching the runway end for the purpose of departure or to exit the runway.
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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. See NONDIRECTIONAL BEACON
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Blocked (frequently used)

Phraseology used to indicate that a radio transmission has been distorted or interrupted due to multiple simultaneous radio transmissions.
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Braking Action (Good, Fair, Poor, or Nil) (frequently used)

A report of conditions on the airport movement area providing a pilot with a degree/quality of braking that he/she might expect. Braking action is reported in terms of good, fair, poor, or nil.
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Center Weather Advisory

An unscheduled weather advisory issued by Center Weather Service Unit meteorologists for ATC use to alert pilots of existing or anticipated adverse weather conditions within the next 2 hours. A CWA may modify or redefine a SIGMET. See AWW See AIRMET See CONVECTIVE SIGMET See SIGMET Refer to AIM
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Chaff

Thin, narrow metallic reflectors of various lengths and frequency responses, used to reflect radar energy. These reflectors when dropped from aircraft and allowed to drift downward result in large targets on the radar display.
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Chase (frequently used)

An aircraft flown in proximity to another aircraft normally to observe its performance during training or testing.
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Circle to Runway (Runway Number) (frequently used)

Used by ATC to inform the pilot that he/she must circle to land because the runway in use is other than the runway aligned with the instrument approach procedure. When the direction of the circling maneuver in relation to the airport/runway is required, the controller will state the direction (eight cardinal compass points) and specify a left or right downwind or base leg as appropriate; e.g., “Cleared VOR Runway Three Six Approach circle to Runway Two Two,” or “Circle northwest of the airport for a right downwind to Runway Two Two.” See CIRCLE‐TO‐LAND MANEUVER See LANDING MINIMUMS Refer to AIM
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Circle-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. See CIRCLE TO RUNWAY See LANDING MINIMUMS Refer to AIM
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Clearance (frequently used)

See AIR TRAFFIC CLEARANCE
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Clearance Void if Not Off By (Time) (frequently used)

Used by ATC to advise an aircraft that the departure clearance is automatically canceled if takeoff is not made prior to a specified time. The pilot must obtain a new clearance or cancel his/her IFR flight plan if not off by the specified time. See ICAO term CLEARANCE VOID TIME
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Clearance Void Time [ICAO]

A time specified by an air traffic control unit at which a clearance ceases to be valid unless the aircraft concerned has already taken action to comply therewith.
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Cleared (Type of) Approach (frequently used)

ATC authorization for an aircraft to execute a specific instrument approach procedure to an airport; e.g., “Cleared ILS Runway Three Six Approach.” See APPROACH CLEARANCE See INSTRUMENT APPROACH PROCEDURE Refer to 14 CFR Part 91 Refer to AIM
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Cleared Approach (frequently used)

ATC authorization for an aircraft to execute any standard or special instrument approach procedure for that airport. Normally, an aircraft will be cleared for a specific instrument approach procedure. See CLEARED (Type of) APPROACH See INSTRUMENT APPROACH PROCEDURE Refer to 14 CFR Part 91 Refer to AIM
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Cleared as Filed (frequently used)

Means the aircraft is cleared to proceed in accordance with the route of flight filed in the flight plan. This clearance does not include the altitude, DP, or DP Transition. See REQUEST FULL ROUTE CLEARANCE Refer to AIM
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Cleared for Takeoff (frequently used)

ATC authorization for an aircraft to depart. It is predicated on known traffic and known physical airport conditions.
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Cleared for the Option (frequently used)

ATC authorization for an aircraft to make a touch‐and‐go, low approach, missed approach, stop and go, or full stop landing at the discretion of the pilot. It is normally used in training so that an instructor can evaluate a student's performance under changing situations. See OPTION APPROACH Refer to AIM
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Cleared Through (frequently used)

ATC authorization for an aircraft to make intermediate stops at specified airports without refiling a flight plan while en route to the clearance limit.
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Cleared to Land (frequently used)

ATC authorization for an aircraft to land. It is predicated on known traffic and known physical airport conditions.
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Climb to VFR (frequently used)

ATC authorization for an aircraft to climb to VFR conditions within Class B, C, D, and E surface areas when the only weather limitation is restricted visibility. The aircraft must remain clear of clouds while climbing to VFR. See SPECIAL VFR CONDITIONS Refer to AIM
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Clutter

In radar operations, clutter refers to the reception and visual display of radar returns caused by precipitation, chaff, terrain, numerous aircraft targets, or other phenomena. Such returns may limit or preclude ATC from providing services based on radar. See CHAFF See GROUND CLUTTER See PRECIPITATION See TARGET See ICAO term RADAR CLUTTER
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Compass Locator

A low power, low or medium frequency (L/MF) radio beacon installed at the site of the outer or middle marker of an instrument landing system (ILS). It can be used for navigation at distances of approximately 15 miles or as authorized in the approach procedure.
  1. Outer Compass Locator (LOM)- A compass locator installed at the site of the outer marker of an instrument landing system. See OUTER MARKER
  2. Middle Compass Locator (LMM)- A compass locator installed at the site of the middle marker of an instrument landing system. See MIDDLE MARKER See ICAO term LOCATOR

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Contact Approach (frequently used)

An approach wherein an aircraft on an IFR flight plan, having an air traffic control authorization, operating clear of clouds with at least 1 mile flight visibility and a reasonable expectation of continuing to the destination airport in those conditions, may deviate from the instrument approach procedure and proceed to the destination airport by visual reference to the surface. This approach will only be authorized when requested by the pilot and the reported ground visibility at the destination airport is at least 1 statute mile. Refer to AIM
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Convective SIGMET (frequently used)

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. See AIRMET See AWW See CWA See SIGMET Refer to AIM
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Cross (Fix) at (Altitude) (frequently used)

Used by ATC when a specific altitude restriction at a specified fix is required.
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Cross (Fix) at or above (Altitude) (frequently used)

Used by ATC when an altitude restriction at a specified fix is required. It does not prohibit the aircraft from crossing the fix at a higher altitude than specified; however, the higher altitude may not be one that will violate a succeeding altitude restriction or altitude assignment. See ALTITUDE RESTRICTION Refer to AIM
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Cross (Fix) at or below (Altitude) (frequently used)

Used by ATC when a maximum crossing altitude at a specific fix is required. It does not prohibit the aircraft from crossing the fix at a lower altitude; however, it must be at or above the minimum IFR altitude. See ALTITUDE RESTRICTION See MINIMUM IFR ALTITUDES Refer to 14 CFR Part 91
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Cruise (frequently used)

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: a. 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 shall make the letdown in accordance with a standard/special instrument approach procedure for that airport, or b. 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. See INSTRUMENT APPROACH PROCEDURE
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CWA

See CENTER WEATHER ADVISORY and WEATHER ADVISORY
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Decision Altitude / Decision Height [ICAO]

A specified altitude or height (A/H) in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established.
Note 1: Decision altitude [DA] is referenced to mean sea level [MSL] and decision height [DH] is referenced to the threshold elevation.
Note 2: The required visual reference means that section of the visual aids or of the approach area which should have been in view for sufficient time for the pilot to have made an assessment of the aircraft position and rate of change of position, in relation to the desired flight path.

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Decision Height

With respect to the operation of aircraft, means the height at which a decision must be made during an ILS, MLS, or PAR instrument approach to either continue the approach or to execute a missed approach. See ICAO term DECISION ALTITUDE/DECISION HEIGHT
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Digital Target

A computer-generated symbol representing an aircraft's position, based on a primary return or radar beacon reply, shown on a digital display.
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Digitized Target

A computer-generated indication shown on an analog radar display resulting from a primary radar return or a radar beacon reply.
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Direct (frequently used)

Straight line flight between two navigational aids, fixes, points, or any combination thereof. When used by pilots in describing off-airway routes, points defining direct route segments become compulsory reporting points unless the aircraft is under radar contact.
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Emergency (frequently used)

A distress or an urgency condition.
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Execute Missed Approach (frequently used)

Instructions issued to a pilot making an instrument approach which means continue inbound to the missed approach point and execute the missed approach procedure as described on the Instrument Approach Procedure Chart or as previously assigned by ATC. The pilot may climb immediately to the altitude specified in the missed approach procedure upon making a missed approach. No turns should be initiated prior to reaching the missed approach point. When conducting an ASR or PAR approach, execute the assigned missed approach procedure immediately upon receiving instructions to "execute missed approach." Refer to AIM
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Expect (Altitude) at (Time) or (Fix) (frequently used)

Used under certain conditions to provide a pilot with an altitude to be used in the event of two-way communications failure. It also provides altitude information to assist the pilot in planning. Refer to AIM
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Expect Further Clearance (Time) (frequently used)

The time a pilot can expect to receive clearance beyond a clearance limit.
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Expect Further Clearance Via (Airways, Routes, or Fixes) (frequently used)

Used to inform a pilot of the routing he/she can expect if any part of the route beyond a short range clearance limit differs from that filed.
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Expedite (frequently used)

Used by ATC when prompt compliance is required to avoid the development of an imminent situation. Expedite climb/descent normally indicates to a pilot that the approximate best rate of climb/descent should be used without requiring an exceptional change in aircraft handling characteristics.
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Final (frequently used)

Commonly used to mean that an aircraft is on the final approach course or is aligned with a landing area. See FINAL APPROACH COURSE See FINAL APPROACH‐IFR See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE
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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:
    1. A landing can be made; or
    2. A missed approach procedure is initiated.

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Final Approach Course

A bearing/radial/track of an instrument approach leading to a runway or an extended runway centerline all without regard to distance.
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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 for precision approaches; or when ATC directs a lower‐than‐published glideslope/path intercept altitude, it is the resultant actual point of the glideslope/path intercept. See FINAL APPROACH POINT See GLIDESLOPE INTERCEPT ALTITUDE See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE
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Final Approach Point

The point, applicable only to a nonprecision approach with no depicted FAF (such as an on airport VOR), where the aircraft is established inbound on the final approach course from the procedure turn and where the final approach descent may be commenced. The FAP serves as the FAF and identifies the beginning of the final approach segment. See FINAL APPROACH FIX See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE
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Final Approach Segment [ICAO]

That segment of an instrument approach procedure in which alignment and descent for landing are accomplished.
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Final Approach-IFR

The flight path of an aircraft which is inbound to an airport on a final instrument approach course, beginning at the final approach fix or point and extending to the airport or the point where a circle‐to‐land maneuver or a missed approach is executed. See FINAL APPROACH COURSE See FINAL APPROACH FIX See FINAL APPROACH POINT See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE See ICAO term FINAL APPROACH
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Flight Level (frequently used)

A level of constant atmospheric pressure related to a reference datum of 29.92 inches of mercury. Each is stated in three digits that represent hundreds of feet. For example, flight level (FL) 250 represents a barometric altimeter indication of 25,000 feet; FL 255, an indication of 25,500 feet. See ICAO term FLIGHT LEVEL
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Flight Level [ICAO]

A surface of constant atmospheric pressure which is related to a specific pressure datum, 1013.2 hPa (1013.2 mb), and is separated from other such surfaces by specific pressure intervals.
Note 1: A pressure type altimeter calibrated in accordance with the standard atmosphere: a. When set to a QNH altimeter setting, will indicate altitude; b. When set to a QFE altimeter setting, will indicate height above the QFE reference datum; and c. When set to a pressure of 1013.2 hPa (1013.2 mb), may be used to indicate flight levels.
Note 2: The terms `height' and `altitude,' used in Note 1 above, indicate altimetric rather than geometric heights and altitudes.

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FRC (frequently used)

See REQUEST FULL ROUTE CLEARANCE
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Glidepath [ICAO]

A descent profile determined for vertical guidance during a final approach.
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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/MLS, 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. PAR. Used by ATC to inform an aircraft making a PAR approach of its vertical position (elevation) relative to the descent profile.
See ICAO term GLIDEPATH
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Glideslope Intercept Altitude

The minimum altitude to intercept the glideslope/path on a precision approach. The intersection of the published intercept altitude with the glideslope/path, designated on Government charts by the lightning bolt symbol, is the precision FAF; however, when the approach chart shows an alternative lower glideslope intercept altitude, and ATC directs a lower altitude, the resultant lower intercept position is then the FAF. See FINAL APPROACH FIX See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE
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Go Ahead (frequently used)

Proceed with your message. Not to be used for any other purpose.
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Go Around (frequently used)

Instructions for a pilot to abandon his/her approach to landing. Additional instructions may follow. Unless otherwise advised by ATC, a VFR aircraft or an aircraft conducting visual approach should overfly the runway while climbing to traffic pattern altitude and enter the traffic pattern via the crosswind leg. A pilot on an IFR flight plan making an instrument approach should execute the published missed approach procedure or proceed as instructed by ATC; e.g., "Go around" (additional instructions if required). See LOW APPROACH See MISSED APPROACH
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Ground Clutter

A pattern produced on the radar scope by ground returns which may degrade other radar returns in the affected area. The effect of ground clutter is minimized by the use of moving target indicator (MTI) circuits in the radar equipment resulting in a radar presentation which displays only targets which are in motion. See CLUTTER
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Have Numbers (frequently used)

Used by pilots to inform ATC that they have received runway, wind, and altimeter information only.
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Homing (frequently used)

Flight toward a NAVAID, without correcting for wind, by adjusting the aircraft heading to maintain a relative bearing of zero degrees. See BEARING See ICAO term HOMING
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Homing [ICAO]

The procedure of using the direction‐finding equipment of one radio station with the emission of another radio station, where at least one of the stations is mobile, and whereby the mobile station proceeds continuously towards the other station.
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How Do You Hear Me? (frequently used)

A question relating to the quality of the transmission or to determine how well the transmission is being received.
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I Say Again (frequently used)

The message will be repeated.
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Ident (frequently used)

A request for a pilot to activate the aircraft transponder identification feature. This will help the controller to confirm an aircraft identity or to identify an aircraft. Refer to AIM
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If No Transmission Received For (Time) (frequently used)

Used by ATC in radar approaches to prefix procedures which should be followed by the pilot in event of lost communications. See LOST COMMUNICATIONS
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IFR Takeoff Minimums and Departure Procedures

Title 14 Code of Federal Regulations Part 91, prescribes standard takeoff rules for certain civil users. At some airports, obstructions or other factors require the establishment of nonstandard takeoff minimums, departure procedures, or both to assist pilots in avoiding obstacles during climb to the minimum en route altitude. Those airports are listed in FAA/DOD Instrument Approach Procedures (IAPs) Charts under a section entitled "IFR Takeoff Minimums and Departure Procedures." The FAA/DOD IAP chart legend illustrates the symbol used to alert the pilot to nonstandard takeoff minimums and departure procedures. When departing IFR from such airports or from any airports where there are no departure procedures, DPs, or ATC facilities available, pilots should advise ATC of any departure limitations. Controllers may query a pilot to determine acceptable departure directions, turns, or headings after takeoff. Pilots should be familiar with the departure procedures and must assure that their aircraft can meet or exceed any specified climb gradients.
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Immediately (Frequently used)

Used by ATC or pilots when such action compliance is required to avoid an imminent situation.
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Initial Approach Segment [ICAO]

That segment of an instrument approach procedure between the initial approach fix and the intermediate approach fix or, where applicable, the final approach fix or point.
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Inner Marker

A marker beacon used with an ILS (CAT II) precision approach located between the middle marker and the end of the ILS runway, transmitting a radiation pattern keyed at six dots per second and indicating to the pilot, both aurally and visually, that he/she is at the designated decision height (DH), normally 100 feet above the touchdown zone elevation, on the ILS CAT II approach. It also marks progress during a CAT III approach. See INSTRUMENT LANDING SYSTEM Refer to AIM
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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. See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE Refer to 14 CFR Part 91 Refer to AIM
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Instrument Landing System

A precision instrument approach system which normally consists of the following electronic components and visual aids:
  1. Localizer. See LOCALIZER
  2. Glideslope. See GLIDESLOPE
  3. Outer Marker. See OUTER MARKER
  4. Middle Marker. See MIDDLE MARKER
  5. Approach Lights. See AIRPORT LIGHTING
Refer to 14 CFR Part 91 Refer to AIM
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Intermediate Approach Segment [ICAO]

That segment of an instrument approach procedure between either the intermediate approach fix and the final approach fix or point, or between the end of a reversal, race track or dead reckoning track procedure and the final approach fix or point, as appropriate.
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Interrogator

The ground-based surveillance radar beacon transmitter-receiver, which normally scans in synchronism with a primary radar, transmitting discrete radio signals which repetitiously request all transponders on the mode being used to reply. The replies received are mixed with the primary radar returns and displayed on the same plan position indicator (radar scope). Also, applied to the airborne element of the TACAN/DME system. See TRANSPONDER Refer to AIM
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Jamming

Electronic or mechanical interference which may disrupt the display of aircraft on radar or the transmission/reception of radio communications/navigation.
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Landing Minimums

The minimum visibility prescribed for landing a civil aircraft while using an instrument approach procedure. The minimum applies with other limitations set forth in 14 CFR Part 91 with respect to the Minimum Descent Altitude (MDA) or Decision Height (DH) prescribed in the instrument approach procedures as follows:
  1. Straight-in landing minimums. A statement of MDA and visibility, or DH and visibility, required for a straight-in landing on a specified runway, or
  2. Circling minimums. A statement of MDA and visibility required for the circle-to-land maneuver.
Note: Descent below the established MDA or DH is not authorized during an approach unless the aircraft is in a position from which a normal approach to the runway of intended landing can be made and adequate visual reference to required visual cues is maintained.
See CIRCLE-TO-LAND MANEUVER See DECISION HEIGHT See INSTRUMENT APPROACH PROCEDURE See MINIMUM DESCENT ALTITUDE See STRAIGHT-IN LANDING See VISIBILITY Refer to 14 CFR Part 91
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Localizer

The component of an ILS which provides course guidance to the runway. See INSTRUMENT LANDING SYSTEM See ICAO term LOCALIZER COURSE Refer to AIM
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Localizer Course [ICAO]

The locus of points, in any given horizontal plane, at which the DDM (difference in depth of modulation) is zero.
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Locator [ICAO]

An LM/MF NDB used as an aid to final approach.
Note: A locator usually has an average radius of rated coverage of between 18.5 and 46.3 km (10 and 25 NM).

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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 to 14 CFR Part 91 Refer to AIM
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Low Approach

An approach over an airport or runway following an instrument approach or a VFR approach including the go-around maneuver where the pilot intentionally does not make contact with the runway. Refer to AIM
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Maintain (frequently used)

  1. Concerning altitude/flight level, the term means to remain at the altitude/flight level specified. The phrase "climb and" or "descend and" normally precedes "maintain" and the altitude assignment; e.g., "descend and maintain 5,000."
  2. Concerning other ATC instructions, the term is used in its literal sense; e.g., maintain VFR.

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Make Short Approach (frequently used)

Used by ATC to inform a pilot to alter his/her traffic pattern so as to make a short final approach. See TRAFFIC PATTERN
Related Posts:
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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. See INNER MARKER See MIDDLE MARKER See OUTER MARKER Refer to AIM
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Mayday (frequently used)

The international radiotelephony distress signal. When repeated three times, it indicates imminent and grave danger and that immediate assistance is requested. See PAN-PAN Refer to AIM
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Middle Marker

A marker beacon that defines a point along the glideslope of an ILS normally located at or near the point of decision height (ILS Category I). It is keyed to transmit alternate dots and dashes, with the alternate dots and dashes keyed at the rate of 95 dot/dash combinations per minute on a 1300 Hz tone, which is received aurally and visually by compatible airborne equipment. See INSTRUMENT LANDING SYSTEM See MARKER BEACON Refer to AIM
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Minimum Crossing Altitude

The lowest altitude at certain fixes at which an aircraft must cross when proceeding in the direction of a higher minimum en route IFR altitude (MEA). See MINIMUM EN ROUTE IFR ALTITUDE
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Minimum Descent Altitude

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. See NONPRECISION APPROACH PROCEDURE
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Minimum En Route IFR Altitude (MEA)

The lowest published altitude between radio fixes which assures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes. The MEA prescribed for a Federal airway or segment thereof, area navigation low or high route, or other direct route applies to the entire width of the airway, segment, or route between the radio fixes defining the airway, segment, or route. Refer to 14 CFR Part 91 Refer to 14 CFR Part 95 Refer to AIM
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Minimum IFR Altitudes (MIA)

Minimum altitudes for IFR operations as prescribed in 14 CFR Part 91. These altitudes are published on aeronautical charts and prescribed in 14 CFR Part 95 for airways and routes, and in 14 CFR Part 97 for standard instrument approach procedures. If no applicable minimum altitude is prescribed in 14 CFR Part 95 or 14 CFR Part 97, the following minimum IFR altitude applies:
  1. In designated mountainous areas, 2,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown; or
  2. Other than mountainous areas, 1,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown; or
  3. As otherwise authorized by the Administrator or assigned by ATC.
See MINIMUM CROSSING ALTITUDE See MINIMUM EN ROUTE IFR ALTITUDE See MINIMUM OBSTRUCTION CLEARANCE ALTITUDE See MINIMUM SAFE ALTITUDE See MINIMUM VECTORING ALTITUDE Refer to 14 CFR Part 91
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Minimum Obstruction Clearance Altitude (MOCA)

The lowest published altitude in effect between radio fixes on VOR airways, off-airway routes, or route segments which meets obstacle clearance requirements for the entire route segment and which assures acceptable navigational signal coverage only within 25 statute (22 nautical) miles of a VOR. Refer to 14 CFR Part 91 Refer to 14 CFR Part 95
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Minimum Safe Altitude

  1. The minimum altitude specified in 14 CFR Part 91 for various aircraft operations.
  2. Altitudes depicted on approach charts which provide at least 1,000 feet of obstacle clearance for emergency use within a specified distance from the navigation facility upon which a procedure is predicated. These altitudes will be identified as Minimum Sector Altitudes or Emergency Safe Altitudes and are established as follows:
    1. Minimum Sector Altitudes. Altitudes depicted on approach charts which provide at least 1,000 feet of obstacle clearance within a 25-mile radius of the navigation facility upon which the procedure is predicated. Sectors depicted on approach charts must be at least 90 degrees in scope. These altitudes are for emergency use only and do not necessarily assure acceptable navigational signal coverage.
    2. See ICAO term Minimum Sector Altitude
    3. Emergency Safe Altitudes. Altitudes depicted on approach charts which provide at least 1,000 feet of obstacle clearance in nonmountainous areas and 2,000 feet of obstacle clearance in designated mountainous areas within a 100-mile radius of the navigation facility upon which the procedure is predicated and normally used only in military procedures. These altitudes are identified on published procedures as "Emergency Safe Altitudes."

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Minimum Sector Altitude [ICAO]

The lowest altitude which may be used under emergency conditions which will provide a minimum clearance of 300 m (1,000 feet) above all obstacles located in an area contained within a sector of a circle of 46 km (25 NM) radius centered on a radio aid to navigation.
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Minimum Vectoring Altitude (MVA)

The lowest MSL altitude at which an IFR aircraft will be vectored by a radar controller, except as otherwise authorized for radar approaches, departures, and missed approaches. The altitude meets IFR obstacle clearance criteria. It may be lower than the published MEA along an airway or J-route segment. It may be utilized for radar vectoring only upon the controller's determination that an adequate radar return is being received from the aircraft being controlled. Charts depicting minimum vectoring altitudes are normally available only to the controllers and not to pilots. Refer to AIM
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Missed Approach (frequently used)

  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.
See MISSED APPROACH POINT Refer to AIM
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Missed Approach Point

A point prescribed in each instrument approach procedure at which a missed approach procedure shall be executed if the required visual reference does not exist. See MISSED APPROACH See SEGMENTS OF AN INSTRUMENT APPROACH PROCEDURE
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Missed Approach Procedure [ICAO]

The procedure to be followed if the approach cannot be continued.
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Negative (frequently used)

"No," or "permission not granted," or "that is not correct."
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Negative Contact (frequently used)

Used by pilots to inform ATC that:
  1. Previously issued traffic is not in sight. It may be followed by the pilot's request for the controller to provide assistance in avoiding the traffic.
  2. They were unable to contact ATC on a particular frequency.

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No Gyro Approach (frequently used)

A radar approach/vector provided in case of a malfunctioning gyro-compass or directional gyro. Instead of providing the pilot with headings to be flown, the controller observes the radar track and issues control instructions "turn right/left" or "stop turn" as appropriate. Refer to AIM
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No Transgression Zone (NTZ) (frequently used)

The NTZ is a 2,000 foot wide zone, located equidistant between parallel runway final approach courses in which flight is not allowed.
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Nondirectional Beacon

An L/MF or UHF radio beacon transmitting nondirectional signals whereby the pilot of an aircraft equipped with direction finding equipment can determine his/her bearing to or from the radio beacon and "home" on or track to or from the station. When the radio beacon is installed in conjunction with the Instrument Landing System marker, it is normally called a Compass Locator. See AUTOMATIC DIRECTION FINDER See COMPASS LOCATOR
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Nonprecision Approach Procedure

A standard instrument approach procedure in which no electronic glideslope is provided; e.g., VOR, TACAN, NDB, LOC, ASR, LDA, or SDF approaches.
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NORDO (frequently used)

(No Radio)- Aircraft that cannot or do not communicate by radio when radio communication is required are referred to as “NORDO.” See LOST COMMUNICATIONS
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Numerous Targets Vicinity (Location) (frequently used)

A traffic advisory issued by ATC to advise pilots that targets on the radar scope are too numerous to issue individually. See TRAFFIC ADVISORIES
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On Course (frequently used)

  1. Used to indicate that an aircraft is established on the route centerline.
  2. Used by ATC to advise a pilot making a radar approach that his/her aircraft is lined up on the final approach course.
See ON-COURSE INDICATION
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On-Course Indication

An indication on an instrument, which provides the pilot a visual means of determining that the aircraft is located on the centerline of a given navigational track, or an indication on a radar scope that an aircraft is on a given track.
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Option Approach

An approach requested and conducted by a pilot which will result in either a touch-and-go, missed approach, low approach, stop-and-go, or full stop landing. See CLEARED FOR THE OPTION Refer to AIM
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Out (frequently used)

The conversation is ended and no response is expected.
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Outer Marker

A marker beacon at or near the glideslope intercept altitude of an ILS approach. It is keyed to transmit two dashes per second on a 400 Hz tone, which is received aurally and visually by compatible airborne equipment. The OM is normally located four to seven miles from the runway threshold on the extended centerline of the runway. See INSTRUMENT LANDING SYSTEM See MARKER BEACON Refer to AIM
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Over (frequently used)

My transmission is ended; I expect a response.
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Pan-Pan

The international radio-telephony urgency signal. When repeated three times, indicates uncertainty or alert followed by the nature of the urgency. See MAYDAY Refer to AIM
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Pilot's Discretion (frequently used)

When used in conjunction with altitude assignments, means that ATC has offered the pilot the option of starting climb or descent whenever he/she wishes and conducting the climb or descent at any rate he/she wishes. He/she may temporarily level off at any intermediate altitude. However, once he/she has vacated an altitude, he/she may not return to that altitude.
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Precipitation

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

An analog or digital target, exclusive of a secondary radar target, presented on a radar display.
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Radar

A device which, by measuring the time interval between transmission and reception of radio pulses and correlating the angular orientation of the radiated antenna beam or beams in azimuth and/or elevation, provides information on range, azimuth, and/or elevation of objects in the path of the transmitted pulses.
  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.
See INTERROGATOR See TRANSPONDER See ICAO term RADAR Refer to AIM
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Radar [ICAO]

A radio detection device which provides information on range, azimuth and/or elevation of objects.
  1. Primary Radar- Radar system which uses reflected radio signals.
  2. Secondary Radar- Radar system wherein a radio signal transmitted from a radar station initiates the transmission of a radio signal from another station.

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Radar Clutter [ICAO]

The visual indication on a radar display of unwanted signals.
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Radar Contact (frequently used)

  1. Used by ATC to inform an aircraft that it is identified on the radar display and radar flight following will be provided until radar identification is terminated. Radar service may also be provided within the limits of necessity and capability. When a pilot is informed of "radar contact," he/she automatically discontinues reporting over compulsory reporting points.
    • See RADAR CONTACT LOST
    • See RADAR FLIGHT FOLLOWING
    • See RADAR SERVICE
    • See RADAR SERVICE TERMINATED
    • Refer to AIM
  2. The term used to inform the controller that the aircraft is identified and approval is granted for the aircraft to enter the receiving controllers airspace.
    • See ICAO term RADAR CONTACT

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Radar Contact [ICAO]

The situation which exists when the radar blip or radar position symbol of a particular aircraft is seen and identified on a radar display.
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Radar Contact Lost (frequently used)

Used by ATC to inform a pilot that radar data used to determine the aircraft's position is no longer being received, or is no longer reliable and radar service is no longer being provided. The loss may be attributed to several factors including the aircraft merging with weather or ground clutter, the aircraft operating below radar line of sight coverage, the aircraft entering an area of poor radar return, failure of the aircraft transponder, or failure of the ground radar equipment. See CLUTTER See RADAR CONTACT
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Radar Flight Following

The observation of the progress of radar identified aircraft, whose primary navigation is being provided by the pilot, wherein the controller retains and correlates the aircraft identity with the appropriate target or target symbol displayed on the radar scope. See RADAR CONTACT See RADAR SERVICE Refer to AIM
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Radar Service

A term which encompasses one or more of the following services based on the use of radar which can be provided by a controller to a pilot of a radar identified aircraft.
  1. Radar Monitoring- The radar flight-following of aircraft, whose primary navigation is being performed by the pilot, to observe and note deviations from its authorized flight path, airway, or route. When being applied specifically to radar monitoring of instrument approaches; i.e., with precision approach radar (PAR) or radar monitoring of simultaneous ILS/MLS approaches, it includes advice and instructions whenever an aircraft nears or exceeds the prescribed PAR safety limit or simultaneous ILS/MLS no transgression zone. See ADDITIONAL SERVICES See TRAFFIC ADVISORIES
  2. Radar Navigational Guidance- Vectoring aircraft to provide course guidance.
  3. Radar Separation- Radar spacing of aircraft in accordance with established minima.
See ICAO term RADAR SERVICE
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Radar Service [ICAO]

Term used to indicate a service provided directly by means of radar.
  1. Monitoring- The use of radar for the purpose of providing aircraft with information and advice relative to significant deviations from nominal flight path.
  2. Separation- The separation used when aircraft position information is derived from radar sources.

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Radar Service Terminated (frequently used)

Used by ATC to inform a pilot that he/she will no longer be provided any of the services that could be received while in radar contact. Radar service is automatically terminated, and the pilot is not advised in the following cases:
  1. An aircraft cancels its IFR flight plan, except within Class B airspace, Class C airspace, a TRSA, or where Basic Radar service is provided.
  2. An aircraft conducting an instrument, visual, or contact approach has landed or has been instructed to change to advisory frequency.
  3. An arriving VFR aircraft, receiving radar service to a tower-controlled airport within Class B airspace, Class C airspace, a TRSA, or where sequencing service is provided, has landed; or to all other airports, is instructed to change to tower or advisory frequency.
  4. An aircraft completes a radar approach.

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Read Back (frequently used)

Repeat my message back to me.
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Report (frequently used)

Used to instruct pilots to advise ATC of specified information; e.g., "Report passing Hamilton VOR."
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Request Full Route Clearance (frequently used)

Used by pilots to request that the entire route of flight be read verbatim in an ATC clearance. Such request should be made to preclude receiving an ATC clearance based on the original filed flight plan when a filed IFR flight plan has been revised by the pilot, company, or operations prior to departure.
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Resume Normal Speed (frequently used)

Used by ATC to advise a pilot that previously issued speed control restrictions are deleted. An instruction to "resume normal speed" does not delete speed restrictions that are applicable to published procedures of upcoming segments of flight, unless specifically stated by ATC. This does not relieve the pilot of those speed restrictions which are applicable to 14 CFR Section 91.117.
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Resume Own Navigation (frequently used)

Used by ATC to advise a pilot to resume his/her own navigational responsibility. It is issued after completion of a radar vector or when radar contact is lost while the aircraft is being radar vectored. See RADAR CONTACT LOST See RADAR SERVICE TERMINATED
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Roger (frequently used)

I have received all of your last transmission. It should not be used to answer a question requiring a yes or a no answer. See AFFIRMATIVE See NEGATIVE
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Runway Heading (frequently used)

The magnetic direction that corresponds with the runway centerline extended, not the painted runway number. When cleared to "fly or maintain runway heading," pilots are expected to fly or maintain the heading that corresponds with the extended centerline of the departure runway. Drift correction shall not be applied; e.g., Runway 4, actual magnetic heading of the runway centerline 044, fly 044.
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Safety Alert

A safety alert issued by ATC to aircraft under their control if ATC is aware the aircraft is at an altitude which, in the controller's judgment, places the aircraft in unsafe proximity to terrain, obstructions, or other aircraft. The controller may discontinue the issuance of further alerts if the pilot advises he/she is taking action to correct the situation or has the other aircraft in sight.
  1. Terrain/Obstruction Alert- A safety alert issued by ATC to aircraft under their control if ATC is aware the aircraft is at an altitude which, in the controller's judgment, places the aircraft in unsafe proximity to terrain/obstructions; e.g., "Low Altitude Alert, check your altitude immediately."
  2. Aircraft Conflict Alert- A safety alert issued by ATC to aircraft under their control if ATC is aware of an aircraft that is not under their control at an altitude which, in the controller's judgment, places both aircraft in unsafe proximity to each other. With the alert, ATC will offer the pilot an alternate course of action when feasible; e.g., "Traffic Alert, advise you turn right heading zero niner zero or climb to eight thousand immediately."
Note: The issuance of a safety alert is contingent upon the capability of the controller to have an awareness of an unsafe condition. The course of action provided will be predicated on other traffic under ATC control. Once the alert is issued, it is solely the pilot's prerogative to determine what course of action, if any, he/she will take.

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Say Again (frequently used)

Used to request a repeat of the last transmission. Usually specifies transmission or portion thereof not understood or received; e.g., "Say again all after ABRAM VOR."
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Say Altitude (frequently used)

Used by ATC to ascertain an aircraft's specific altitude/flight level. When the aircraft is climbing or descending, the pilot should state the indicated altitude rounded to the nearest 100 feet.
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Say Heading (frequently used)

Used by ATC to request an aircraft heading. The pilot should state the actual heading of the aircraft.
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Secondary Radar Target

A target derived from a transponder return presented on a radar display.
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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. 
    See ICAO term INITIAL APPROACH SEGMENT
  2. Intermediate Approach- The segment between the intermediate fix or point and the final approach fix.
    See ICAO term INTERMEDIATE APPROACH SEGMENT
  3. Final Approach- The segment between the final approach fix or point and the runway, airport, or missed approach point.
    See ICAO term FINAL APPROACH SEGMENT
  4. 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 to 14 CFR Part 97
    See ICAO term MISSED APPROACH PROCEDURE

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Severe Weather Forecast Alerts

Preliminary messages issued in order to alert users that a Severe Weather Watch Bulletin (WW) is being issued. These messages define areas of possible severe thunderstorms or tornado activity. The messages are unscheduled and issued as required by the Storm Prediction Center (SPC) at Norman, Oklahoma. See AIRMET See CONVECTIVE SIGMET See CWA See SIGMET
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SIGMET (frequently used)

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. See AIRMET See AWW See CONVECTIVE SIGMET See CWA See ICAO term SIGMET INFORMATION Refer to AIM
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SIGMET Information [ICAO]

Information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of aircraft operations.
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Speak Slower (frequently used)

Used in verbal communications as a request to reduce speech rate.
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Special VFR Conditions

Meteorological conditions that are less than those required for basic VFR flight in Class B, C, D, or E surface areas and in which some aircraft are permitted flight under visual flight rules. See SPECIAL VFR OPERATIONS Refer to 14 CFR Part 91
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Special VFR Flight [ICAO]

A VFR flight cleared by air traffic control to operate within Class B, C, D, and E surface areas in meteorological conditions below VMC.
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Special VFR Operations

Aircraft operating in accordance with clearances within Class B, C, D, and E surface areas in weather conditions less than the basic VFR weather minima. Such operations must be requested by the pilot and approved by ATC. See SPECIAL VFR CONDITIONS See ICAO term SPECIAL VFR FLIGHT
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Speed Adjustment

An ATC procedure used to request pilots to adjust aircraft speed to a specific value for the purpose of providing desired spacing. Pilots are expected to maintain a speed of plus or minus 10 knots or 0.02 Mach number of the specified speed. Examples of speed adjustments are:
  1. "Increase/reduce speed to Mach point (number.)"
  2. "Increase/reduce speed to (speed in knots)" or "Increase/reduce speed (number of knots) knots."

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Squawk (Mode, Code, Function) (frequently used)

Activate specific modes/codes/functions on the aircraft transponder; e.g., "Squawk three/alpha, two one zero five, low." See TRANSPONDER
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Stand By (frequently used)

Means the controller or pilot must pause for a few seconds, usually to attend to other duties of a higher priority. Also means to wait as in "stand by for clearance." The caller should reestablish contact if a delay is lengthy. "Stand by" is not an approval or denial.
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Stop Altitude Squawk (frequently used)

Used by ATC to inform an aircraft to turn-off the automatic altitude reporting feature of its transponder. It is issued when the verbally reported altitude varies 300 feet or more from the automatic altitude report. See ALTITUDE READOUT See TRANSPONDER
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Stop Squawk (Mode or Code) (frequently used)

Used by ATC to tell the pilot to turn specified functions of the aircraft transponder off. See STOP ALTITUDE SQUAWK See TRANSPONDER
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Stop Stream (frequently used)

Used by ATC to request a pilot to suspend electronic attack activity. See JAMMING
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Straight-In Approach IFR

An instrument approach wherein final approach is begun without first having executed a procedure turn, not necessarily completed with a straight-in landing or made to straight-in landing minimums. See LANDING MINIMUMS See STRAIGHT-IN APPROACH VFR See STRAIGHT-IN LANDING
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Straight-In Approach VFR

Entry into the traffic pattern by interception of the extended runway centerline (final approach course) without executing any other portion of the traffic pattern. See TRAFFIC PATTERN
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Straight-In Landing

A landing made on a runway aligned within 30° of the final approach course following completion of an instrument approach. See STRAIGHT-IN APPROACH IFR
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Target

The indication shown on an analog display resulting from a primary radar return or a radar beacon reply. See ASSOCIATED See DIGITAL TARGET See DIGITIZED TARGET See PRIMARY RADAR TARGET See RADAR See SECONDARY RADAR TARGET See TARGET SYMBOL See ICAO term TARGET See UNASSOCIATED
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Target [ICAO]

In radar:
  1. Generally, any discrete object which reflects or retransmits energy back to the radar equipment.
  2. Specifically, an object of radar search or surveillance.

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Target Symbol

A computer‐generated indication shown on a radar display resulting from a primary radar return or a radar beacon reply.
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Taxi Patterns

Patterns established to illustrate the desired flow of ground traffic for the different runways or airport areas available for use.
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That is Correct (frequently used)

The understanding you have is right.
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Traffic Advisories

Advisories issued to alert pilots to other known or observed air traffic which may be in such proximity to the position or intended route of flight of their aircraft to warrant their attention. Such advisories may be based on:
  1. Visual observation.
  2. Observation of radar identified and nonidentified aircraft targets on an ATC radar display, or
  3. Verbal reports from pilots or other facilities.
Note 1: The word “traffic” followed by additional information, if known, is used to provide such advisories; e.g., “Traffic, 2 o'clock, one zero miles, southbound, eight thousand.”
Note 2: Traffic advisory service will be provided to the extent possible depending on higher priority duties of the controller or other limitations; e.g., radar limitations, volume of traffic, frequency congestion, or controller workload. Radar/ nonradar traffic advisories do not relieve the pilot of his/her responsibility to see and avoid other aircraft. Pilots are cautioned that there are many times when the controller is not able to give traffic advisories concerning all traffic in the aircraft's proximity; in other words, when a pilot requests or is receiving traffic advisories, he/she should not assume that all traffic will be issued.
Refer to AIM
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Traffic in Sight (frequently used)

Used by pilots to inform a controller that previously issued traffic is in sight. See NEGATIVE CONTACT See TRAFFIC ADVISORIES
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Traffic No Factor (frequently used)

Indicates that the traffic described in a previously issued traffic advisory is no factor.
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Traffic No Longer Observed (frequently used)

Indicates that the traffic described in a previously issued traffic advisory is no longer depicted on radar, but may still be a factor.
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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 upwind leg, crosswind leg, downwind leg, base leg, and final approach.
  1. Upwind Leg- A flight path parallel to the landing runway in the direction of landing.
  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.
  5. 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.
See STRAIGHT‐IN APPROACH VFR See TAXI PATTERNS See ICAO term AERODROME TRAFFIC CIRCUIT Refer to 14 CFR Part 91 Refer to AIM
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Transmitting in the Blind (frequently used)

A transmission from one station to other stations in circumstances where two‐way communication cannot be established, but where it is believed that the called stations may be able to receive the transmission.
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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. See INTERROGATOR See ICAO term TRANSPONDER Refer to AIM
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Transponder [ICAO]

A receiver/transmitter which will generate a reply signal upon proper interrogation; the interrogation and reply being on different frequencies.
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Unable (frequently used)

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

A radar target that does not display a data block with flight identification and altitude information. See ASSOCIATED
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Verify (frequently used)

Request confirmation of information; e.g., “verify assigned altitude.”
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Verify Specific Direction of Takeoff (or Turns After Takeoff) (frequently used)

Used by ATC to ascertain an aircraft's direction of takeoff and/or direction of turn after takeoff. It is normally used for IFR departures from an airport not having a control tower. When direct communication with the pilot is not possible, the request and information may be relayed through an FSS, dispatcher, or by other means. See IFR TAKEOFF MINIMUMS AND DEPARTURE PROCEDURES
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VFR Conditions (frequently used)

Weather conditions equal to or better than the minimum for flight under visual flight rules. The term may be used as an ATC clearance/instruction only when:
  1. An IFR aircraft requests a climb/descent in VFR conditions.
  2. The clearance will result in noise abatement benefits where part of the IFR departure route does not conform to an FAA approved noise abatement route or altitude.
  3. A pilot has requested a practice instrument approach and is not on an IFR flight plan.
    Note: All pilots receiving this authorization must comply with the VFR visibility and distance from cloud criteria in 14 CFR Part 91. Use of the term does not relieve controllers of their responsibility to separate aircraft in Class B and Class C airspace or TRSAs as required by FAAO JO 7110.65. When used as an ATC clearance/instruction, the term may be abbreviated “VFR;” e.g., “MAINTAIN VFR,” “CLIMB/DESCEND VFR,” etc.

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VFR Not Recommended (frequently used)

An advisory provided by a flight service station to a pilot during a preflight or inflight weather briefing that flight under visual flight rules is not recommended. To be given when the current and/or forecast weather conditions are at or below VFR minimums. It does not abrogate the pilot's authority to make his/her own decision.
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VFR-On-Top (frequently used)

ATC authorization for an IFR aircraft to operate in VFR conditions at any appropriate VFR altitude (as specified in 14 CFR and as restricted by ATC). A pilot receiving this authorization must comply with the VFR visibility, distance from cloud criteria, and the minimum IFR altitudes specified in 14 CFR Part 91. The use of this term does not relieve controllers of their responsibility to separate aircraft in Class B and Class C airspace or TRSAs as required by FAAO JO 7110.65.
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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 to 14 CFR Part 91 Refer to AIM
  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 Visibility Value (RVV)- The visibility determined for a particular runway by a transmissometer. A meter provides a continuous indication of the visibility (reported in miles or fractions of miles) for the runway. RVV is used in lieu of prevailing visibility in determining minimums for a particular runway.
  5. 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 is used in lieu of RVV and/or prevailing visibility in determining minimums for a particular runway.
    1. Touchdown RVR- The RVR visibility readout values obtained from RVR equipment serving the runway touchdown zone.
    2. Mid‐RVR- The RVR readout values obtained from RVR equipment located midfield of the runway.
    3. Rollout RVR- The RVR readout values obtained from RVR equipment located nearest the rollout end of the runway.
See ICAO term VISIBILITY
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Visibility [ICAO]

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.
  1. Flight Visibility-The visibility forward from the cockpit of an aircraft in flight.
  2. Ground Visibility-The visibility at an aerodrome as reported by an accredited observer.
  3. Runway Visual Range [RVR]-The range over which the pilot of an aircraft on the centerline of a runway can see the runway surface markings or the lights delineating the runway or identifying its centerline.

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Weather Advisory

In aviation weather forecast practice, an expression of hazardous weather conditions not predicted in the area forecast, as they affect the operation of air traffic and as prepared by the NWS. See AIRMET See SIGMET
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When Able (frequently used)

When used in conjunction with ATC instructions, gives the pilot the latitude to delay compliance until a condition or event has been reconciled. Unlike "pilot discretion," when instructions are prefaced "when able," the pilot is expected to seek the first opportunity to comply. Once a maneuver has been initiated, the pilot is expected to continue until the specifications of the instructions have been met. "When able," should not be used when expeditious compliance is required.
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Wilco (frequently used)

I have received your message, understand it, and will comply with it.
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Words Twice (frequently used)

  1. As a request: "Communication is difficult. Please say every phrase twice."
  2. As information: "Since communications are difficult, every phrase in this message will be spoken twice."

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