Appendix 1 APPENDIX 1
DEFINITIONS AND ACRONYMS This Appendix contains the definition of terms and acronyms used within this Advisory Circular (AC). The appendix also contains certain terms that are not used in this AC but are used in related ACs and are included for convenient reference. Certain definition of terms and acronyms are also provided to facilitate common use of this Appendix for other related ACs.
Some of the definitions and terminology used in this AC are used to describe new operational concepts and technology implementations. Other definitions, including primary and supplemental means of navigation, are evolving terms and are defined in different ways in various documents by the FAA and international aviation community. Although this AC provides a baseline of new definitions and terminology, these updates have not been harmonized throughout the FAA or with the international aviation community.
Definitions Actual Navigation Performance A measure of the current estimated navigation performance, excluding Flight Technical Error (FTE).
Actual Navigation Performance is measured in terms of accuracy and integrity, and may be affected by the type and availability of navigation signals and equipment.
Note: Also see Estimated Position Uncertainty (EPU).
Aeronautical Chart Critical Data Data for Aeronautical charts determined IAW RTCA or ICAO Annex 4 criteria considered to have a very low probability of significant error and very high probability of validity (e.g., Perror per unit data element <1 X 10-8 ) Aeronautical Chart Essential Data Data for Aeronautical charts determined IAW RTCA or ICAO Annex 4 criteria considered to have a low probability of significant error and high probability of validity (e.g., Perror per unit data element <1 X 10-5 ) Aeronautical Chart Routine Data Data for Aeronautical charts determined IAW RTCA or ICAO Annex 4 criteria considered to have a routine possibility of significant error and routine validity
(e.g., Perror per unit data element <1 X 10-3) Approach Intercept Waypoint (APIWP) A variable waypoint used when necessary to link a barometric LNAV/VNAV flight path with a Final Approach Segment (FAS) that is fixed in space (e.g., an xLS final segment). The APIWP permits LNAV and barometric VNAV segments, which may vary vertically in location on an approach as a function of barometric pressure setting or temperature variation from standard, to join or be connected to a FAS which is otherwise fixed in vertical location with respect to a runway.
Appendix 1 Automatic Dependent Surveillance (ADS) A surveillance technique in which aircraft automatically provide, via data link, data derived from on-board navigation and position fixing systems, including aircraft identification, four dimensional position and additional data as appropriate (ICAO - IS&RP Annex 6).
Alert Height A height above the runway based on the characteristics of the aircraft and its failoperational landing system, above which a Category III approach would be discontinued and a missed approach initiated if a failure occurred in one of the redundant parts of the fail operational landing system, or in the relevant ground equipment. (ICAO - IS&RP Annex 6).
Airborne Navigation System The airborne equipment that senses and computes the aircraft position relative to the defined path and provides information to the displays and to the flight guidance system. It may include a number of receivers and/or system computers such as a Flight Management Computer and typically provides inputs to the Flight Guidance System.
Automatic Go-Around A Go-Around which is accomplished by an autopilot following pilot selection and initiation of the “Go-Around” autopilot mode.
Availability An expectation that systems or elements required for an operations will be available to perform their intended functions so that the operation will be accomplished as planned to an acceptable level of probability.
Balked Landing A discontinued landing attempt. Term is often used in conjunction with aircraft configuration or performance assessment, as in “Balked landing climb gradient;”
Also see “Rejected Landing.”
Catastrophic Failure Condition Failure condition which would result in multiple fatalities, usually with the loss of the airplane.
Category I (US) (ICAO) An instrument approach or approach and landing with a decision altitude (height) or minimum descent altitude (height) not lower than 60m (200 ft) and with either a visibility not less than 1/2 statute mile (800m), or a runway visual range not less than 550m (1800 ft). (Adapted from ICAO - IS&RP Annex 6).
A precision instrument approach and landing with a decision height not lower than 60m (200 ft) and with either a visibility not less than 800m (2400 ft), or a runway visual range not less than 550m (1800 ft).
(Adapted from ICAO - IS&RP Annex 6).
Category II An instrument approach or approach and landing with a decision height lower than 60m (200 ft) but not lower than 30m (100 ft) and a runway visual range not less than 350m (1200 ft). (Adapted from ICAO - IS&RP Annex 6).
Category III An instrument approach or approach and landing with a decision height lower than 30m (100 ft), or no decision height, or a runway visual range less than 350m (1200 ft). (Adapted from ICAO - IS&RP Annex 6).
Category IIIa An instrument approach and landing with a decision height lower than 30m (100 ft), or no decision height and a runway visual range not less than 200m (700 ft).
(Adapted from ICAO - IS&RP Annex 6).
Category IIIb An instrument approach and landing with a decision height lower than 15m (50 ft), or no decision height and a runway visual range less than 200m (700 ft) but not less than 50m (150 ft). (Adapted from ICAO - IS&RP Annex 6).
FAA Note - the United States does not use Decision Heights for Category IIIb.
Appendix 1 Category IIIc An instrument approach and landing with or without a decision height, with a runway visual range less than 50m (150 ft).
(Adapted from ICAO - IS&RP Annex 6).
Certificate Holding District Office (CHDO) That FAA Flight Standards District Office (FSDO), Certificate Management Office (CMO), or Certificate Management Unit (CMU) assigned by FAA to have operating certificate oversight responsibility for a particular operator.
Class I Navigation Navigation within the service volume of an ICAO Standard NAVAID.
Class II Navigation A flight operation or portion of a flight operation (irrespective of the means of navigation) which takes place outside (beyond) the designated Operational Service Volume of an ICAO standard airway navigation facility or NAVAID
(e.g., VOR, VOR/DME, NDB).
Combiner The element of the HUD in which the pilot simultaneously views the external visual scene along with synthetic information provided in symbolic form.
Command Information Information that directs the pilot to follow a course of action in a specific situation (e.g., Flight Director).
Conformal Information Information which correctly overlays the image of the real world, irrespective of the pilot's viewing position.
Datum Crossing Height (DCH) The height of the Flight Path Control Point (FPCP) above the Runway Datum Point (RDP).
Note: The FPCP may be specified in units of feet or meters, but is typically specified in units of feet.
Decision Altitude (DA) A specified altitude 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. (Adapted from ICAO - IS&RP Annex 6).
Decision Altitude (Height) (DA(H)) For Category I, a specified minimum altitude in an approach by which a missed approach must be initiated if the required visual reference to continue the approach has not been established. The “Altitude” value is typically measured by a barometric altimeter or equivalent (e.g., Inner Marker) and is the determining factor for minima for Category I Instrument Approach Procedures. The “Height” value specified in parenthesis is typically a radio altitude equivalent height above the touchdown zone (HAT) used only for advisory reference and does not necessarily reflect actual height above underlying terrain.
For Category II and certain Category III procedures (e.g., when using a Fail- Passive autoflight system) the Decision Height (or an equivalent IM position fix) is the controlling minima, and the altitude value specified is advisory. The altitude value is available for cross reference. Use of a barometrically referenced DA for Category II is not currently authorized for 14 CFR part 121, 129, or 135 operations at U.S. facilities (Adapted from ICAO - IS&RP Annex 6).
Decision Height (DH) A specified height 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 (Adapted from ICAO - IS&RP Annex 6).
Defined Flight Path The flight path as determined by the path definition function of an aircraft’s navigation system.
Appendix 1 Design Eye Box The three dimensional volume in space surrounding the Design Eye Position from which the Head Up Display (HUD) information can be viewed.
Design Eye Position The position at each pilot’s station from which a seated pilot achieves the optimum combination of outside visibility and instrument scan.
Desired Flight Path The path that the pilot, or pilot and air traffic service, expect the aircraft to fly.
Earth Centered, Earth Fixed (ECEF) A cartesian coordinate reference system by which GNSS receivers determine a 3- dimensional coordinate frame, and that later is transformed into latitude and longitude measurements (e.g., fixed relative to earth reference and does not vary with barometric pressure).
Enhanced Vision System (EVS) An electronic means to provide the flightcrew with a sensor derived or enhanced image of the external scene (e.g., Millimeter wave radar, FLIR).
Estimate of Position Uncertainty (EPU), or Estimated Position Error (EPE) A measure based on a scale which conveys the current position estimation performance - Also called Estimated Position Error (EPE) Extended Final Approach Segment (EFAS) That segment of an approach, co-linear with the Final Approach Segment, but which extends beyond the Glidepath Intercept Waypoint (GPIWP) or Approach Intercept Waypoint (APIWP).
External Visual Reference Information the pilot derives from visual observation of real world cues outside the cockpit.
Extremely Improbable A probability of occurrence on the order of 1 x 10 -9 or less per hour of flight, or per event (e.g., takeoff, landing).
Extremely Remote A probability of occurrence between the orders of 1 x 10-9 and 1 x 10-7 per hourof flight, or per event (e.g., takeoff, landing).
Fail Operational System A system capable of completing the specified phases of an operation following the failure of any single system component after passing a point designated by the applicable safety analysis (e.g., Alert Height).
Fail Passive System A system which, in the event of a failure, causes no significant deviation of aircraft flight path or attitude.
Field of View As applied to a Head Up Display (HUD) - the angular extent of the display that can be seen from within the design eye box.
Final Approach Course (FAC) The final bearing/radial/track of an instrument approach leading to a runway, without regard to distance. For certain previously designed approach procedures that are not aligned with a runway, the FAC bearing/radial/track of an instrument approach may lead to the extended runway centerline, rather than to alignment with the runway.
Final Approach Fix (FAF) The fix from which the final approach to an airport is executed. For standard procedures that do not involve multiple approach segments intercepting the runway centerline near the runway, the FAF typically identifies the beginning of the straight-in final approach segment.
Final Approach Point (FAP) The point applicable to instrument approaches other than ILS, MLS, or GLS, with no depicted FAF (e.g., only applies to approaches such as an on-airport VOR or NDB), where the aircraft is established inbound on the final approach course from a procedure turn, and where descent to the next procedurally specified altitude, or to minimum altitude, may be commenced.
Appendix 1 Final Approach Segment (FAS) The segment of an approach extending from the Glidepath Intercept Waypoint (GPIWP) or Approach Intercept Waypoint (APIWP), whichever occurs later, to the Glidepath Intercept Reference Point (GIRP). For the purpose of procedure construction, The Final Approach segment is defined as beginning at the FAF and ending at the Flight Path Control Point (FPCP) or point at which the missed approach segment starts (e.g., point of lowest nominal DA(H)).
Flight Guidance System The means available to the flightcrew to maneuver the aircraft in a specific manner either manually or automatically. It may include a number of components such as the autopilot, flight directors, and relevant display and annunciation elements, and it typically accepts inputs from the airborne navigation system.
Flight Path Alignment Point (FPAP) The FPAP is a point, usually at or near the stop end of a runway, used in conjunction with the RDP and a vector normal to the WGS-84 ellipsoid at the RDP, to define the geodesic plane of a final approach and landing flight path
(e.g., FAS and RWS). The FPAP typically may be the RDP for the reciprocal runway.
Flight Path Control Point (FPCP) The Flight Path Control Point (FPCP) is a calculated point located above the RDP in a direction normal to the WGS-84 ellipsoid. The FPCP is used to establish the vertical descent path and descent angle of the final approach flight path
(e.g., FAS) to the landing runway.
Flight Technical Error (FTE) The accuracy with which the aircraft is controlled as measured by the indicated aircraft position with respect to the indicated command or defined flight path position.
Note: FTE does not include human performance conceptual errors, typically which may be of large magnitude (e.g., entry of an incorrect waypoint or waypoint position, selection of an incorrect procedure, selection of an incorrect NAVAID frequency, failure to select a proper flight guidance mode. FTE can be influenced by factors such as flightcrew response to guidance (e.g., response to Flight Director information), or external environment conditions such as a wind gradient or turbulence).
“Fly By” Vertical Waypoint A “Fly By” vertical waypoint (WP) is a WP for which an aircraft may initiate a vertical rate or flight path angle change to depart the current segment of a specified vertical path (VNAV path) shortly prior to an active WP, in order to expeditiously capture the next vertical path segment without overshoot.
“Fly Over” Vertical Waypoint A “Fly Over” vertical waypoint (WP) is a WP for which an aircraft must stay on the defined vertical path (VNAV path) until passing an active WP and may not initiate capture of the next vertical path segment until after passing the active WP.
Frequent Occurring more often than 1 in 1000 events or 1000 flight hours.
Glide Path Angle (GPA) The glide path angle is an angle, defined at the FPCP, that establishes the descent gradient for the final approach flight path (e.g., FAS) of an instrument approach procedure. It is measured in the geodesic plane of the approach (defined by the RDP, FPAP, and a vector normal to the WGS-84 ellipsoid at the RDP). The vertical and horizontal references for the GPA are a vector normal to the WGS-84 ellipsoid at the RDP and a plane perpendicular to that vector at the FPCP, respectively.
Glide Path Intercept Waypoint (GPIWP) The point at which the established glide slope intercept altitude (MSL) meets the Final Approach Segment (FAS), on a standard day, using a standard altimeter setting (1013.2 HPa or 29.92 in).
Appendix 1 Glidepath Intercept Reference Point (GIRP) The GIRP is the point at which the extension of the final approach path
(e.g., FAS) intercepts the runway.
GNSS Landing System (GLS) A differential GNSS (e.g., GPS) based landing system providing both vertical and lateral position fixing capability. Note: Term may be applied to any GNSS based differentially corrected landing system providing lateral and vertical service for approach and landing equivalent to or better than that provided by a U.S. Type I ILS, or equivalent ILS specified by ICAO Annex 10.
Global Positioning System (GPS) The NAVSTAR Global Positioning System operated by the United States Department of Defense. It is a satellite -based radio navigation system composed of space, control, and user segments. The space segment is composed of satellites. The control segment is composed of monitor stations, ground antennas, and a master control station. The user segment consists of antennas and receiverprocessors that derive time and compute a position and velocity from the data transmitted from the satellites.
Global Navigation Satellite System [GNSS] A world wide position, velocity and time determination system that uses one or more satellite constellations.
Go-around A transition from an approach to a stabilized climb.
Guidance Information used during manual control, automatic control, or monitoring of automatic control of an aircraft that is of sufficient quality to be used by itself for the intended purpose of achieving a particular flight path .
Hazardous Failure Condition Failure Conditions which would reduce the capability of the airplane or the ability of the crew to cope with adverse operating conditions to the extent that there would be:
(i) A large reduction in safety margins or functional capabilities;
(ii) Physical distress or higher workload such that the flightcrew cannot be relied upon to perform their tasks accurately or completely; or
(iii) Serious or fatal injury to a relatively small number of the occupants.
Head Up Display System An aircraft system which provides head up guidance to the pilot during flight. It includes the display element, sensors, computers and power supplies, indications, and controls. It may receive inputs from an airborne navigation system or flight guidance system.
Hybrid System A combination of two or more systems of dissimilar design used to perform a particular operation.
Improbable A probability of occurrence greater than 1 x 10-9 but less than or equal to 1 x 10-5 per hour of flight, or per event (e.g., takeoff, landing).
Independent Landing Monitor (ILM) A millimeter wave radar-based sensor (e.g., typically transmitting at 35 GHz, or 94 GHz) used to present a perspective display of a runway to a pilot on an electronic flight deck display during approach, to serve as an independent integrity monitor for another type of landing NAVAID sensor (e.g., ILS, MLS or GLS).
Independent Systems A system that is not adversely influenced by the operation, computation, or failure of some other identical, related, or separate system (e.g., two separate ILS receivers).
Infrequent Occurring less often than 1 in 1000 events or 1000 flight hours.
Appendix 1 Initial Missed Approach Waypoint (IMAWP) A Waypoint generally aligned with the runway centerline, beyond the touchdown zone, used to establish a suitable initial climb segment beyond the touchdown zone. The IMAWP intends to provide a safe path and altitude, if applicable, in the vicinity of the runway, to be used to establish a safe initial go-around path following a low altitude go-around or rejected landing.
Initial Missed Approach Segment (IMAS) That segment of an approach from the Glide Path Intercept Waypoint (GIRP) to the Initial Missed Approach Waypoint (IMAWP).
Instantaneous Field of View The angular extent of a HUD display which can be seen from either eye from a fixed position of the head.
Integrity A measure of the acceptability of a system or system element, to contribute to the required safety of an operation.
Landing For the purpose of this AC, landing will begin at 100 ft., the DH or the AH to the first contact of the wheels with the runway.
Landing Rollout For the purpose of this AC, rollout starts from the first contact of the wheels with the runway and finishes when the airplane has slowed to a safe taxi speed (in the order of 30 knots).
Major Failure Condition Failure Condition which would reduce the capability of the airplane or the ability of the crew to cope with adverse operating conditions to the extent that there would be, for example, a significant reduction in safety margins or functional capabilities, a significant increase in crew workload or in conditions impairing crew efficiency, or discomfort to occupants, possibly including injuries.
Minimum Descent Altitude (Height) (MDA(H)) See individual definitions below for MDA and MDH.
Minimum Descent Altitude (MDA) A specified altitude in a non-precision approach or circling approach below which descent must not be made without the required visual reference. Minimum Descent Altitude (MDA) is referenced to mean sea level.
(ICAO - IS&RP Annex 6).
Minimum Descent Height (MDH) A specified height in an instrument approach other than ILS, MLS, or GLS, or a circling approach, below which descent must not be made without the required visual reference. Minimum Descent Height (MDH) is referenced to aerodrome elevation or to the threshold if that is more than 7 ft. (2m) below the aerodrome elevation. An MDH for a circling approach is referenced to the aerodrome elevation. (ICAO - IS&RP Annex 6).
FAA Note - The U.S. does not use Minimum Descent Heights.
Minimum Use Height (MUH) A height specified during airworthiness demonstration or review above which, under standard or specified conditions, a probable failure of a system is not likely to cause a significant path displacement unacceptably reducing flight path clearance from specified reference surfaces (e.g., airport elevation) or specified obstacle clearance surfaces.
Minor Failure Condition Failure Condition which would not significantly reduce airplane safety and which involve crew actions that are well within their capabilities. Minor Failure Conditions may include, for example, a slight reduction in safety margins or functional capabilities, a slight increase in crew workload, such as routine flight plan changes, or some inconvenience to occupants.
Appendix 1 Missed Approach The flight path followed by an aircraft after discontinuation of an approach procedure and initiation of a go-around. Typically a “missed approach” follows a published missed approach segment of an instrument approach procedure, or follows radar vectors to a missed approach point, return to landing, or diversion to an alternate.
Missed Approach Segment (MAS) That segment of an instrument approach procedure from a point on the FAS corresponding to the position where the lowest DA(H) occurs under nominal conditions, to the designated IMAWP, or missed approach holding WP, as specified for the procedure.
Monitored Head Up Display (HUD) A HUD which has internal or external capability to reliably detect erroneous sensor inputs or guidance outputs, to ensure that a pilot does not receive incorrect or misleading guidance, failure, or status information.
Navigation System Error An error in the estimation of the aircraft’s position. Also called “position estimation error”.
Non-Normal Means of Navigation A means of navigation which does not satisfy one or more of the necessary levels of accuracy, integrity, and availability for a particular area, route, procedure, or operation, and which may require use of a pilot’s “emergency authority” to continue navigation.
Non-normal Conditions Conditions other than those considered normal conditions or rare-normal conditions (e.g., Failure conditions, certain kinds of error conditions ) NOTAM Notice to Airmen - A notice distributed by means of telecommunication containing information concerning the establishment, condition, or change in any aeronautical facility, service, procedure, or hazard, the timely knowledge of which is essential to personnel concerned with flight operations. (ICAO - IS&RP Annex
6).
Path Definition Error The difference between the desired path and the defined path.
Note: This error may be due to survey errors, database resolution limitations, or other such factors.
Path Steering Error Any resulting difference (i.e., non-zero deviation) between the estimated aircraft position from the desired flight path.
Note: This error includes any display errors along with flight technical error.
Performance A measure of the accuracy with which an aircraft, a system, or an element of a system operates compared against specified parameters. Performance demonstration(s) typically include the component of Flight Technical Error (FTE).
Position Estimation Error An error in the estimation of the aircraft’s position. Also called “Navigation System Error.”
Primary Means of Navigation A means of navigation which satisfies the necessary levels of accuracy andintegrity for a particular area, route, procedure, or operation. The failure of a “Primary Means” of navigation may result in, or require reversion to, a “nonnormal” means of navigation, or an alternate level of RNP.
“Rare-Normal” conditions A condition which must be expected to normally occur, but does so only very infrequently (e.g., unusually strong winds, significant wind gradients, significant turbulence, significant in-flight icing, significant mountain wave activity)
Appendix 1 Redundant The presence of more than one independent means for accomplishing a given function or flight operation. Each means need not necessarily be identical.
Rejected Landing A discontinued landing attempt. A rejected landing typically is initiated at low altitude but prior to touchdown. If from or following an instrument approach it typically is considered to be initiated below DA(H) or MDA(H). A rejected landing may be initiated in either VMC or IMC. A rejected landing typically leads to or results in a “go around,” and if following an instrument approach, a “Missed Approach.” If related to consideration of aircraft configuration(s) or performance it is sometime referred to as a “Balked Landing.” The term “rejected landing” is used to be consistent with regulatory references such as found in 14 CFR part 121 Appendix E, and policy references as in FAA Order 8400.10.
Remote A probability of occurrence on the order of greater than 1 x 10-7 but less than or equal to 1 x 10-5 per hour of flight, or per event (e.g., takeoff, landing).
Required Navigation Performance (RNP) A statement of the navigation performance necessary for operation within a defined airspace (Adapted from ICAO - IS&RP Annex 6).
NOTE: Required Navigation Performance is specified in terms of accuracy, integrity, and availability of navigation signals and equipment for a particular airspace, route, procedure, or operation.
Required Navigation Performance Containment (RNP Containment) RNP Containment represents a bound of the rare-normal performance and specified non-normal performance of a system, typically expressed as 2*RNP(X).
When RNP represents Gaussian statistical performance at a two sigma (2 x standard deviation) level, then containment represents a nominal performance bound specified at the level of four sigma (4 x standard deviation). Note: RNP containment use may vary with intended operational applications.
Required Navigation Performance Level or Type (RNP Level or RNP Type) A value typically expressed as a distance in nautical miles from the intended position within which an aircraft would be for at least 95 percent of the total flying time (Adapted from ICAO - IS&RP Annex 6).
NOTE: Applications of RNP to terminal area and other operations may also include a vertical and/or longitudinal component. ICAO may use the term RNP Type, while certain other States, aircraft manuals, procedures, and Operators may use the term RNP Level.
Example - RNP 4 represents a navigation lateral accuracy of plus or minus 4 nm
(7.4 km) on a 95% basis. RNP is typically defined in terms of its lateral accuracy, and has an associated lateral containment boundary.
Required Visual Reference That section of the visual aids or of the approach area which should have been in view for sufficient time for the pilots to have made an assessment of the aircraft’s position and rate of change of position, in relation to the desired flight path. In Category III operations with a decision height, the required visual reference is that specified for the particular procedure and operations (ICAO - IS&RP Annex 6 - Decision Height definition - Note 2).
Runway Datum Point (RDP) The RDP is used in conjunction with the FPAP and a vector normal to the WGS-84 ellipsoid at the RDP to define the geodesic plane of a final approach flight path to the runway for touchdown and rollout. It is a point at the designated lateral center of the landing runway defined by latitude, longitude, and ellipsoidal height. The RDP is typically a surveyed reference point used to connect the approach flight path with the runway. The RDP may or may not necessarily be
Appendix 1 coincident with the designated runway threshold Runway Segment (RWS) That segment of an approach from the Ground Point of Intercept (GPI) to Flight Path Alignment Point (FPAP).
Situation Information Information that directly informs the pilot about the status of the aircraft system operation or specific flight parameters including flight path.
Standard Landing Aid (SLA) A Standard Landing Aid (SLA) is considered to be any navigation service or navigation aid provided by a State which meets internationally accepted performance standards (e.g., ICAO Standards and Recommended Practices (SARPs), or equivalent U.S. or other State standards).
Supplementary Means of Navigation A means of navigation which satisfies one or more of the necessary levels of accuracy, integrity, or availability for a particular area, route, procedure or operation. The failure of a “Supplementary Means” of navigation may result in, or require reversion to, another alternate “normal” means of navigation for the intended route, procedure, or operation.
Synthetic Reference Information provided to the flightcrew by instrumentation or electronic displays, that is electronically generated, processed, enhanced, or otherwise augmented.
Information may be either command or situation information (e.g., SVS, EVS).
Synthetic Vision System (SVS) A system used to create a synthetic image (e.g., typically a computer generated picture) representing the environment external to the airplane.
Take off Guidance System A system which provides directional command guidance to the pilot during a takeoff, or takeoff and aborted takeoff. It includes sensors, computers and power supplies, indications and controls.
Total Field of View The maximum angular extent of the display that can be seen with either eye, allowing head motion within the design eye box.
Total System Error (TSE) The difference between the desired flight path and the actual flight path.
Typically determined by a sum of the path definition error, navigation system error, and the path steering error (i.e., flight technical error plus any display error).
Touch Down Zone (TDZ) The first 3000 ft. of usable runway for landing, unless otherwise specified by the FAA, or other applicable ICAO or State authority (e.g., for STOL aircraft, or IAW an SFAR).
Visual Glide Slope Indicator An electro-optical device that provides a visual indication of vertical position in relation to a defined glidepath. Specific systems in this classification include the Visual Approach Slope Indicator (VASI), the Precision Approach Path Indicator (PAPI), and Precision Landing Aid Slope Indicator (PLASI). This term is defined in FAA Order 8260.3, U.S. Standard for Terminal Instrument Procedures (TERPS).
Visual Guidance Visual information the pilot derives from the observation of real world cues, out the flight deck window, used as a primary reference for aircraft control or flight path assessment.
WGS-84 Ellipsoid A mathematical model of the earth’s shape based on WGS-84 survey information, used as an element of an earth surface-referenced navigation coordinate frame (see appropriate ICAO or RTCA references for its technical definition and specification - e.g., ICAO “World Geodetic System 1984 Manual - DOC 9674- AN/946”).
Appendix 1 Acronyms
ACRONYM EXPANSION ABAS Aircraft Based Augmentation System AC Advisory Circular ACI Adjacent Channel Interface ACO FAA Aircraft Certification Office ADF Automatic Direction Finder ADI Attitude Director Indicator ADS Automatic Dependent Surveillance AEG FAA Aircraft Evaluation Group AFCS Autopilot Flight Control System AFDS Autopilot Flight Director System AFGS Automatic Flight Guidance System AFM Airplane Flight Manual AH Alert Height AHI All Weather Harmonization Items AIP Aeronautical Information Publication ALS Approach Light System ANP Actual Navigation Performance APIWP Approach Intercept Waypoint APM Aircrew Program Manager APU Auxiliary Power Unit AQP Advanced Qualification Program ARA Airborne Radar Approach ASR Airport Surveillance Radar ATC Air Traffic Control ATIS Automatic Terminal Information Service ATOGW Allowable Takeoff Gross Weight ATPC Airline Transport Pilot Certificate ATS Air Traffic Service AWO All Weather Operations BARO [Abbreviation for “Barometric”] BC Back Course (e.g., ILS Back Course)
Appendix 1 BITE Built-In Test Equipment CAA Civil Aviation Authority CDL Configuration Deviation List CFR Code of Federal Regulations CFR Crash Fire Rescue CHDO Certificate Holding District Office CL Centerline Lights CMO FAA Certificate Management Office CMU FAA Certificate Management Unit CNS Communication, Navigation, and Surveillance CRM Collision Risk Model CRM Crew Resource Management CVR Cockpit Voice Recorder DA Decision Altitude DA(H) Decision Altitude(Height) DCH Datum Crossing Height DD DME-DME updating DDM Difference of Depth Modulation DEP Design Eye Position DGNSS Differential Global Navigation Satellite System DH Decision Height DME Distance Measuring Equipment DOD (U.S.) Department of Defense DOT (U.S.) Department of Transportation DP Departure Procedure EADI Electronic Attitude Director Indicator ECEF Earth Centered Earth Fixed (coordinate frame) EFAS Extended Final Approach Segment EGPWS Enhanced Ground Proximity Warning System EHSI Electronic Horizontal Situation Indicator EPE Estimated Position Error EPU Estimated Position Uncertainty EROPS Extended Range Operations (any number of engines) ET Elapsed Time