Aeronautical Terms
14 CFR
Title 14 of the Code of Federal Regulations
91K
Part 91 Subpart K (14 CFR)
A-RNP
Advanced Required Navigation Performance
A/FD
Airport/Facility Directory
ABAS
Aircraft-Based Augmentation System
AC
Advisory Circular
ACO
Aircraft Certification Office (FAA)
AEG
Aircraft Evaluation Group
AFCS
Automatic Flight Control System
AFM
Airplane Flight Manual
AFMS
Airplane Flight Manual Supplement
AGL
Above Ground Level
AIP
Aeronautical Information Publication
AIR
Aircraft Certification Service
Air Traffic Control (ATC) Service
1. Area Control Service, 2. Approach Control Service, and 3. Airport Control Service.
Air Traffic Service (ATS)
A generic term meaning: 1. Flight Information Services (FIS), 2. Alerting Service, and 3. Air Traffic Advisory Service.
Air Traffic Service (ATS) Routes
The term “ATS Route” is a generic term that includes “VOR Federal airways,” “colored Federal airways,” “jet routes,” and “RNAV routes.” The term “ATS route” does not replace these more familiar route names, but serves only as an overall title when listing the types of routes that comprise the United States route structure.
AIRAC
Aeronautical Information Regulation and Control
Aircraft-Based Augmentation System (ABAS)
An augmentation system that augments and/or integrates the information obtained from the other Global Positioning System (GPS) elements with information onboard the aircraft. The most common form of ABAS is receiver autonomous integrity monitoring (RAIM).
Airworthiness Approval Criteria
Found in Advisory Circular (AC) 20-138 ( ), Airworthiness Approval of Positioning and Navigation Systems.
AMC
Acceptable Means of Compliance
ANP
Actual Navigation Performance
ANSP
Air Navigation Service Provider
AP
Autopilot
Area Navigation (RNAV)
A method of navigation which permits aircraft operation on any desired flightpath 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. RNAV includes Performance-based Navigation (PBN) as well as other operations that do not meet the definition of PBN.
Area Navigation (RNAV) System
A navigation system which permits aircraft operation on any desired flightpath 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. A RNAV system may be included as part of a flight management system (FMS).
ARINC
Aeronautical Radio Incorporated
ATC
Air Traffic Control
ATRK
Along-Track
ATS
Air Traffic Service
baro-VNAV
Barometric Vertical Navigation
Barometric Vertical Navigation (baro-VNAV)
A function of certain RNAV systems which presents computed vertical guidance to the pilot referenced to a specified vertical path. The computed vertical guidance is based on barometric altitude information and is typically computed as a geometric path between two waypoints or an angle based on a single waypoint.
CA
Course to Altitude (path terminator per ARINC Specification 424)
CDI
Course Deviation Indicator
CF
Course to Fix (path terminator per ARINC Specification 424)
CHDO
Certificate-Holding District Office
CMO
Certificate Management Office
CPDLC
Controller-Pilot Data Link Communications
CTA
Control Area
CTA/FIR
Control Area/Flight Information Region
D/D
DME/DME
D/D/I
DME/DME/Inertial
DA
Decision Altitude
Decision Altitude (DA)
In an approach with vertical guidance, DA is a specified altitude expressed in feet above mean sea level at which a missed approach must be initiated if the required visual references to continue the approach have not been established.
DF
Direct to Fix
Discontinuity
A discontinuity is an interruption in the sequence of waypoints within the active onboard flight plan (primary flight plan loaded into FMS).
Distance Measuring Equipment
(DME) DME/DME (D/D) RNAV. Refers to navigation using DME ranging from at least two DME facilities to determine position.
DME
Distance Measuring Equipment
DME/DME/Inertial
(D/D/I) RNAV. Refers to navigation using DME ranging from at least two DME facilities to determine position along with use of inertial systems, inertial reference system (IRS) or Inertial Reference Unit (IRU), to provide sufficient position information during limited DME gaps.
DOD
Department of Defense
DP
Departure Procedure
DTK
Desired Track
EFB
Electronic Flight Bag
EHSI
Electronic Horizontal Situation Indicator
EPE
Estimate of Position Error
EPU
Estimate of Position Uncertainty
Estimate of Position Uncertainty (EPU)
A measure based on a defined scale in nautical miles (NM), which conveys the current position estimation performance, also known as Actual Navigation Performance (ANP) or Estimate of Position Error (EPE) in certain aircraft. The EPU is not an estimate of the actual error, but a defined statistical indication of potential error.
ETA
Estimated Time of Arrival
EUROCAE
European Organization for Civil Aviation Equipment
FA
Fix to an Altitude (path terminator per ARINC Specification 424)
FAA
Federal Aviation Administration
FAF
Final Approach Fix
FAS
Final Approach Segment
Fault Detection and Exclusion (FDE)
A RAIM algorithm that can automatically detect and exclude a faulty satellite from the position solution when a sufficient number of redundant satellite measurements are available.
FD
Flight Director
FDE
Fault Detection and Exclusion
FGS
Flight Guidance System
FIR
Flight Information Region
FIS
Flight Information Services
Fixed Radius Transition (FRT)
An arc at a constant (specified) radius that is tangent to both the inbound and outbound en route path segments at an en route fix.
FL
Flight Level
Flight Guidance System (FGS)
A system primarily intended to assist the flightcrew in the basic control and tactical guidance of the airplane. Typically referred to as an autopilot (AP)/flight director (FD)/autothrust system, it may consist of sensors, computers, power supplies, servo-motors/actuators, and indications and controllers necessary for the pilot to manage and supervise the system. For rotorcraft, it can include a FD with a stability augmentation system and/or AP.
Flight Management System (FMS)
An integrated system, consisting of airborne sensor, receiver and computer with both navigation and aircraft performance databases, which provides performance and area navigation guidance to a display and automatic flight control system (AFCS).
Flight Technical Error (FTE) or Path Steering Error (PSE)
ccuracy with which an aircraft is controlled, as measured by the indicated aircraft position with respect to the indicated command or desired position. It does not account for procedural blunder errors.
FLIP
U.S. Flight Information Publication
Flyby Waypoints
Flyby waypoints are used when an aircraft should begin a turn to the next course prior to reaching the waypoint separating the two route segments. This is known as turn anticipation.
Flyover Waypoints
Flyover waypoints are used when the aircraft must fly over the point prior to starting a turn.
FM
Fix to Manual Termination (path terminator per ARINC
FMC
Flight Management Computer
FMS
Flight Management System
FOV
Field of View
FRT
Fixed Radius Transition
FSDO
Flight Standards District Office
FTE
Flight Technical Error
GBAS
Ground Based Augmentation System
Global Navigation Satellite System (GNSS)
GNSS is a generic term for a worldwide position, velocity, and time determination system, which includes one or more satellite constellations, aircraft receivers, and system integrity monitoring. GNSS includes GPS, Satellite-based Augmentation Systems (SBAS) such as the wide area augmentation system (WAAS), Ground Based Augmentation System (GBAS) such as the Local Area Augmentation System (LAAS), Global Orbiting Navigation Satellite System (GLONASS), Galileo, and any other satellite navigation system approved for civil use. GNSS can be augmented as necessary to support the Required Navigation Performance (RNP) for the actual phase of operation.
Global Positioning System (GPS)
GPS is a U.S. satellite-based radio navigation system that provides a positioning service anywhere in the world. The service provided by GPS for civil use is defined in the GPS Standard Positioning System Signal Specification. GPS is the U.S. core GNSS satellite constellation providing space-based positioning, velocity, and time. GPS is composed of space, control, and user elements.
GLONASS
Global Orbiting Navigation Satellite System
GLS
Ground Based Augmentation System (GBAS) Landing System
GNSS
Global Navigation Satellite System
GOMEX
Gulf of Mexico
GPS
Global Positioning System
HEMS
Helicopter Emergency Medical Service
HSpec
Helicopter Specification
IAF
Initial Approach Fix
IAP
Instrument Approach Procedure
ICAO
International Civil Aviation Organization
IF
Initial Fix (path terminator per ARINC Specification 424)
IFP
Instrument Flight Procedure
IFR
Instrument Flight Rules
ILS
Instrument Landing System
INS
Inertial Navigation System
IRS
Inertial Reference System
IRU
Inertial Reference Unit
ISA
International Standard Atmosphere
LAAS
Local Area Augmentation System
Lateral Navigation (LNAV)
The function of RNAV systems that computes, displays, and provides lateral guidance to a profile or path. Sometimes referred to as managed navigation.
LNAV
Lateral Navigation
LOA
Letter of Acceptance
Long-Range Navigation System (LRNS)
n electronic navigation unit that is approved for use under instrument flight rules (IFR) as a primary means of navigation, and has at least one source of navigational input, such as inertial navigation system (INS) and/or GPS.
LP
Localizer Performance without Vertical Guidance
LPV
Localizer Performance with Vertical Guidance
LRN
Long-Range Navigation
LRNS
Long-Range Navigation System
MAP
Missed Approach Procedure
MASPS
Minimum Aviation System Performance Standard
MCDU
Multipurpose Control Display Unit
MDA
Minimum Descent Altitude
MEL
Minimum Equipment List
MNPS
minimum navigation performance specification
MOPS
Minimum Operational Performance Standards
MSpec
Management Specification
NANU
Notice Advisory to Navstar Users
NAS
U.S. National Airspace System
NAT/MNPS
North Atlantic Minimum Navigation Performance Specifications
Nav
Spec Navigation Specification
NAVAID
Navigational Aid
Navigation Application
This is defined as the application of a Nav Spec and the supporting NAVAID infrastructure, to routes, procedures, and/or defined airspace volume, in accordance with the intended airspace concept.
Navigation Specification (Nav Spec)
A set of aircraft and aircrew requirements needed to support PBN operations within a defined airspace. There are two kinds of Nav Spec: 1. RNAV specification. A Nav Spec based on RNAV that does not include the requirement for onboard performance monitoring and alerting, designated by the prefix RNAV (e.g., RNAV 5, RNAV 1). 2. RNP specification. A Nav Spec based on RNAV that includes the requirement for onboard performance monitoring and alerting, designated by the prefix RNP (e.g., RNP 4, RNP APCH).
Navigation System Error (NSE)
NSE or Position Estimation Error (PEE) is the difference between the true position and estimated position.
Navigational Aid (NAVAID) Infrastructure
NAVAID infrastructure refers to space-based and or ground-based NAVAIDs available to meet the requirements in the navigation specification (Nav Spec).
NDB
Non-Directional Beacon
NM
Nautical Mile
NOTAM
Notice to Airmen
NPA
Nonprecision Approach
NSE
Navigation System Error
NWS
National Weather Service
Oceanic
Oceanic airspace is defined as international airspace over oceans where separation and procedures are in accordance with the International Civil Aviation Organization (ICAO). Responsibility for the provision of ATC service in this airspace is delegated to various countries.
ODP
Obstacle Departure Procedure
OEM
Original Equipment Manufacturer
Offshore
Offshore airspace is defined by Title 14 of the Code of Federal Regulations (14 CFR) part 71, §§ 71.31 and 71.71. It is designated in international airspace within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic ATC procedures are applied.
OpSpec
Operation Specification
P-RNAV
Precision Area Navigation (European)
Path Definition Error (PDE)
The difference between defined path and desired path at a specific point.
Path Steering Error (PSE) or Flight Technical Error (FTE)
The difference between the estimated position and the abeam point on the system-defined path.
PBN
Performance-Based Navigation
PDE
Path Definition Error
PEE
Position Estimation Error
Performance-Based Navigation (PBN)
RNAV-based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure (IAP), or in a designated airspace.
PF
Pilot Flying
PFD
Primary Flight Display
PinS
Point in Space
PNF
Pilot-Not-Flying (Pilot Monitoring)
POH
Pilot’s Operating Handbook
POI
Principal Operations Inspector
Position Estimation Error (PEE)
PEE or NSE is the difference between true position and estimated position.
Primary Flight Display (PFD)
A display that provides increased situational awareness to the pilot by replacing the traditional six instruments used for instrument flight with an easy-to-scan display that provides the horizon, airspeed, altitude, Vertical Speed (VS), trend, trim, and rate of turn among other key relevant indications.
Primary Optimum Field of View (FOV).
The vertical and horizontal visual fields relative to the design eye reference point that can be viewed with eye rotation only using foveal or central vision. The values for the horizontal (relative to the normal line of sight) are +/-15 degrees optimum, with +/-35 degrees maximum. The values for the vertical (relative to normal line of sight) are +/-15 degrees optimum, with + 40 degrees up and -20 degrees down maximum (Refer to AC 25-11( ), Electronic Flight Displays). The primary FOV definition should be broad enough to include the center radio stack on 14 CFR part 23 airplanes with “classic”, analog basic ‘T’ instrumentation. For rotorcraft, reference the visibility requirements defined in AC 27-1( ), Certification of Normal Category Rotorcraft, and AC 29-2( ), Certification of Transport Category Rotorcraft.
PSE
Path Steering Error
R/T
Receiver/Transmitter
Radius to Fix (RF) Leg
An RF leg is defined as a constant radius circular path around a defined turn center that starts and terminates at a fix.
RAIM
Receiver Autonomous Integrity Monitoring
Receiver Autonomous Integrity Monitoring (RAIM)
An algorithm that verifies the integrity of the position output using GPS measurements, or GPS measurements and barometric aiding.
Remote Continental
Remote continental airspace is defined as airspace above terrain where line-of-sight communications, independent surveillance and reliable ground-based NAVAIDs is not available. Controllers provide ATSs utilizing procedural control and procedural separation.
Required Navigation Performance (RNP)
RNP is a statement of the 95 percent navigation accuracy performance that meets a specified value for a particular phase of flight or flight segment and incorporates associated onboard performance monitoring and alerting features to notify the pilot when the RNP for a particular phase or segment of a flight is not being met.
RF
Radius to Fix (path terminator per ARINC Specification 424)
RFM
Rotorcraft Flight Manual
RFMS
Rotorcraft Flight Manual Supplement
RNAV
Area Navigation
RNP
Required Navigation Performance
RNP System
An RNAV system which supports onboard performance monitoring and alerting.
RNP Value
The RNP value designates the 95 percent LNAV performance (in NM) and the related monitoring and alerting requirements associated with an RNP instrument flight operation or a particular segment of that instrument flight.
RNP/RNAV Procedure
An RNP/RNAV Procedure includes instrument departure procedures (DP), standard terminal arrivals (STAR), and instrument approaches based on PBN.
S-LRNS
Signal Long-Range Navigation System
SAO
Special Areas of Operation
SAPT
Service Availability Prediction Tool
SB
Service Bulletin
SBAS
Satellite-Based Augmentation System
SFAR
Special Federal Aviation Regulation
SID
Standard Instrument Departure
SIS
Signal in Space
SL
Service Letter
SLOP
Strategic Lateral Offset Procedure
SOC
Statement of Compliance
Specification
424)
STAR
Standard Terminal Arrival
STC
Supplemental Type Certificate
SUPPS
Regional Supplementary Procedures
TC
Type Certificate
TF
Track to Fix (path terminator per ARINC Specification 424)
TOAC
Time of Arrival Control
TOGA
Takeoff/Go-Around
Total System Error (TSE)
The difference between the true position and the desired position and is equal to the vector sum of the FTE, PDE, and NSE.
TSE
Total System Error
TSO
Technical Standard Order
TSOA
Technical Standard Order Authorization
VA
Heading to Altitude (path terminator per ARINC Specification 424)
VI
Heading to Intercept (path terminator per ARINC Specification 424)
VM
Heading to Manual (path terminator per ARINC Specification 424)
VNAV
Vertical Navigation
VOR
Very High Frequency Omni-Directional Range
VS
Vertical Speed
WAAS
Wide Area Augmentation System
Waypoints
A waypoint is a predetermined geographical position that is defined in terms of latitude/longitude coordinates. Waypoints may be a simple named point in space or associated with existing NAVAIDs, intersections, or fixes. A waypoint is most often used to indicate a change in direction, speed, or altitude along the desired path. RNAV procedures make use of both flyover and flyby waypoints.
XTK
Cross-Track
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