Appendix J J-2 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.
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/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.
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.
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.
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.
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). Accuracy 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.
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
Appendix J J-3 (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.
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.
Long-Range Navigation System (LRNS). An 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.
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).
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.
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.
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.
Appendix J J-4 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.
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.
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.
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.
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.
RNAV. See Area Navigation (RNAV) above.
RNP/RNAV Procedure. An RNP/RNAV Procedure includes instrument departure procedures (DP), Standard Terminal Arrivals (STAR), and instrument approaches based on PBN.
Appendix J J-5 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 System. An RNAV system which supports onboard performance monitoring and alerting.
For the purposes of this AC, RNP systems comply with Appendices A through I, as appropriate.
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.
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.
1. 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.
2. Flyover Waypoints. Flyover waypoints are used when the aircraft must fly over the point prior to starting a turn.
Appendix J J-6 J.2 Acronyms.
Table J-1. Acronyms Acronym Meaning 14 CFR Title 14 of the Code of Federal Regulations ABAS Aircraft-Based Augmentation System AC Advisory Circular AED Aircraft Evaluation Division 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 AIRAC Aeronautical Information Regulation and Control AMC Acceptable Means of Compliance ANP Actual Navigation Performance ANSP Air Navigation Service Provider AP Autopilot ARINC Aeronautical Radio Incorporated A-RNP Advanced Required Navigation Performance ATC Air Traffic Control ATRK Along-Track ATS Air Traffic Service baro-VNAV Barometric Vertical Navigation CA Course to Altitude (path terminator per ARINC Specification 424) CDI Course Deviation Indicator CF Course to Fix (path terminator per ARINC Specification 424) 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 DF Direct to Fix DME Distance Measuring Equipment 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 ETA Estimated Time of Arrival EUROCAE European Organization for Civil Aviation Equipment FA Fix to an Altitude (path terminator per ARINC Specification 424)
Appendix J J-7 Acronym Meaning FAA Federal Aviation Administration FAF Final Approach Fix FAS Final Approach Segment FD Flight Director FDE Fault Detection and Exclusion FGS Flight Guidance System FIR Flight Information Region FIS Flight Information Services FL Flight Level FLIP U.S. Flight Information Publication FM Fix to Manual Termination (path terminator per ARINC Specification 424) 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 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 HAA Helicopter Air Ambulance 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 LNAV Lateral Navigation LOA Letter of Acceptance LOA Letter of Authorization 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
Appendix J J-8 Acronym Meaning 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 NAVAID Navigational Aid Nav Spec Navigation Specification NDB Non-Directional Beacon NM Nautical Mile NOTAM Notice to Airmen NPA Nonprecision Approach NSE Navigation System Error NWS National Weather Service ODP Obstacle Departure Procedure OEM Original Equipment Manufacturer OpSpec Operation Specification Part 91K Part 91 Subpart K (14 CFR) PBN Performance-Based Navigation PDE Path Definition Error PEE Position Estimation Error PF Pilot Flying PFD Primary Flight Display PinS Point in Space PM Pilot Monitoring POH Pilot’s Operating Handbook POI Principal Operations Inspector P-RNAV Precision Area Navigation (European) PSE Path Steering Error RAIM Receiver Autonomous Integrity Monitoring 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 APCH Required Navigation Performance Approach RNP AR Required Navigation Performance Authorization Required RNP AR APCH Required Navigation Performance Authorization Required Approach R/T Receiver/Transmitter SAPT Service Availability Prediction Tool SB Service Bulletin
Appendix J J-9 Acronym Meaning SBAS Satellite-Based Augmentation System SID Standard Instrument Departure SIS Signal in Space SL Service Letter SLOP Strategic Lateral Offset Procedure S-LRNS Signal Long-Range Navigation System SOC Statement of Compliance SOP Standard Operating Procedure STAR Standard Terminal Arrival STAR Standard Terminal Arrival Route 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 TSE Total System Error TSO Technical Standard Order TSOA Technical Standard Order Authorization UTA Upper Control Area 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 XTK Cross-Track
Advisory Circular Feedback Form If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by contacting the Flight Technologies and Procedures Division (AFS-400) at 9-AWA-AFS400-Coord@faa.gov or the Flight Standards Directives Management Officer at 9-AWA-AFB-120-Directives@faa.gov.
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