1 5 1 Performance-based Navigation (PBN) 8 ATPL GROUND TRAINING SERIES
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2 7 BOOK ELEVEN EASA - FIRST EDITION REVISED FOR NPA 29
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19 Performance-based Navigation (PBN)
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Explanation O Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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PBN Introdu Introduction ction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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1 Principles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 .0 1 Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 .2 1 Scope Scop e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 .3
Navigation Naviga tion Specificatio Specifications, ns, RNA RNAV V and RNP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Navigation Naviga tion Functional Requirem Requirements ents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Designation o RNP and RNAV Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 20 Use o PBN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 20 Airspace Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 2 Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 .1
Specific RNAV and RNP System Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 Fixed Radius Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 23 Data Processe Processess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 25 PBN Operatio Operations ns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 25 Abnormal Situatio Situations ns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 27 28 Database Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Requirements Requireme nts or Specific RNA RNAV V And RNP Specificatio Specifications ns . . . . . . . . . . . . . . . . . . . . . .29 29 RNP APCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
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P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
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Abbreviations ABAS Aircraf-based augmentation system ADS-B/C Automatic dependent surveillance — broadcast/contract AFM Aircraf flight manual AIP Aeronautical inormation publication AMC Acceptable means o compliance ANSP Air navigation service provider AOC Air operator certificate APV Approach procedure with vertical guidance ATM Air traffic management ATS Air traffic service CC(D)O Continuous climb (descent) operations CDI Course deviation indicator CFIT Controlled flight into terrain CNS Communications, navigation and surveillance CRC Cyclic redundancy check DTED Digital terrain elevation data 9 1
EUROCAE European Organisation or Civil Aviation Equipment
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EUROCONTROL European Organisation or the Saety o Air Navigation FGS Flight guidance system FMS Flight management system FRT Fixed radius transition FTE Flight technical error GBAS Ground-based augmentation system GLS GBAS landing system GNSS Global navigation satellite system GPS Global positioning system GRAS Ground-based regional augmentation system
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Performance-based Navigation (PBN) IAP Instrument approach procedure IFP Instrument flight procedure INS Inertial navigation system IRS Inertial reerence system LOA Letter o authorization/letter o acceptance MCDU Multiunction control and display unit MEL Minimum equipment list MLS Microwave landing system MMEL Master minimum equipment list MNPS Minimum navigation perormance specification MSA Minimum sector altitude MSL Mean sea level NAA National airworthiness authority NSE Navigation system error OEM Original equipment manuacturer OM Operations manual P(S)SR Primary (Secondary) surveillance radar
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RAIM Receiver autonomous integrity monitoring
P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
RF Radius to fix RNAV Area navigation RNP Required navigation perormance SBAS Satellite-based augmentation system SID Standard instrument departure SIS Signal-in-space STAR Standard instrument arrival TLS Target level o saety TSE Total system error VFR Visual flight range VNAV Vertical navigation 4
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Explanation Of Terms Aircraf-based augmentation system (ABAS). An augmentation system that augments and/or integrates the inormation obtained rom the other GNSS elements with inormation available on board the aircraf. The most common orm o ABAS is receiver autonomous integrity monitoring (RAIM). Airspace concept. An airspace concept describes the intended operations within an airspace. Airspace concepts are developed to satisy explicit strategic objectives such as improved saety, increased air traffic capacity and mitigation o environmental impact. Airspace concepts can include details o the practical organization o the airspace and its users based on particular CNS/ATM assumptions, e.g. ATS route structure, separation minima, route spacing and obstacle clearance. Approach procedure with vertical guidance (APV). An instrument procedure which utilizes lateral and vertical guidance but does not meet the requirements established or precision approach and landing operations. AIRAC. Aeronautical Inormation Regulation and Control and stems rom the Annex 15 Aeronautical Inormation Services (AIS) document and defines a series o common dates and an associated standard aeronautical inormation publication procedure or States. Area navigation. A method o navigation which permits aircraf operation on any desired flight path within the coverage o ground or space-based navigation aids or within the limits o the capability o sel-contained aids, or a combination o these. Area navigation includes Perormance-based Navigation as well as other RNAV operations that do not meet the definition o Perormance-based Navigation. Area navigation route. An ATS route established or the use o aircraf capable o employing area navigation. ATS surveillance service. A term used to indicate a service provided directly by means o an ATS surveillance system.
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ATS surveillance system. A generic term meaning variously, ADS-B, PSR, SSR or any comparable ground-based system that enables the identification o aircraf. A comparable ground-based system is one that has been demonstrated, by comparative assessment or other methodology, to have a level o saety and perormance equal to or better than monopulse SSR. Cyclic redundancy check (CRC). A mathematical algorithm applied to the digital expression o data that provides a level o assurance against loss or alteration o data. ECAC. European Civil Aviation Conerence. Established by the International Civil Aviation Organization and the Council o Europe. LPV (Localiser Perormance with Vertical guidance) approach is an RNAV (GPS) approach with minimums that are typically lower than LNAV or LNAV/VNAV approaches. An LPV approach is an approach procedure designed specifically or SBAS environments. Mixed navigation environment. An environment where different navigation specifications may be applied within the same airspace (e.g. RNP 10 routes and RNP 4 routes in the same airspace) or where operations using conventional navigation are allowed in the same airspace with RNAV or RNP applications.
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Performance-based Navigation (PBN) Navigation aid (NAVAID) inrastructure. NAVAID inrastructure reers to space-based and or ground-based NAVAIDs available to meet the requirements in the navigation specification. Navigation application. The application o a navigation specification and the supporting NAVAID inrastructure, to routes, procedures, and/or defined airspace volume, in accordance with the intended airspace concept. The navigation application is one element, along with communications, ATS surveillance and ATM procedures which meet the strategic objectives in a defined airspace concept. Navigation unction. The detailed capability o the navigation system (such as the execution o leg transitions, parallel offset capabilities, holding patterns, navigation databases) required to meet the airspace concept. Navigational unctional requirements are one o the drivers or the selection o a particular navigation specification. Navigation specification. A set o aircraf and aircrew requirements needed to support Perormance-based Navigation operations within a defined airspace. There are two kinds o navigation specification: • RNAV specification. A navigation specification based on area navigation that does not include the requirement or on-board perormance monitoring and alerting, designated by the prefix RNAV, e.g. RNAV 5, RNAV 1. • RNP specification. A navigation specification based on area navigation that includes the requirement or on-board perormance monitoring and alerting, designated by the prefix RNP, e.g. RNP 4, RNP APCH. Perormance-based navigation. Area navigation based on perormance requirements or aircraf operating along an ATS route, on an instrument approach procedure or in a designated airspace. Perormance requirements are expressed in navigation specifications in terms o accuracy, integrity, continuity and unctionality needed or the proposed operation in the context o a particular airspace concept.
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Availability o GNSS SIS or some other NAVAID inrastructure is considered within the airspace concept in order to enable the navigation application.
P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Procedural control. Air traffic control service provided by using inormation derived rom sources other than an ATS surveillance system. Receiver autonomous integrity monitoring (RAIM). A orm o ABAS whereby a GNSS receiver processor determines the integrity o the GNSS navigation signals using only GPS signals or GPS signals augmented with altitude (baro-aiding). This determination is achieved by a consistency check among redundant pseudo-range measurements. At least one additional satellite needs to be available with the correct geometry over and above that needed or the position estimation, or the receiver to perorm the RAIM unction. RNAV operations. Aircraf operations using area navigation or RNAV applications. RNAV operations include the use o area navigation or operations which are not developed in accordance with this manual. RNAV system. A navigation system which permits aircraf operation on any desired flight path within the coverage o station-reerenced navigation aids or within the limits o the capability o sel-contained aids, or a combination o these. An RNAV system may be included as part o a flight management system (FMS).
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RNP route. An ATS route established or the use o aircraf adhering to a prescribed RNP navigation specification. RNP system. An area navigation system which supports on-board perormance monitoring and alerting. Satellite-based augmentation system (SBAS). A wide coverage augmentation system in which the user receives augmentation inormation rom a satellite-based transmitter. Standard instrument arrival (STAR). A designated instrument flight rule (IFR) arrival route linking a significant point, normally on an ATS route, with a point rom which a published instrument approach procedure can be commenced. Standard instrument departure (SID). A designated instrument flight rule (IFR) departure route linking the aerodrome or a specified runway o the aerodrome with a specified significant point, normally on a designated ATS route, at which the en-route phase o a flight commences.
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Performance-based Navigation (PBN) PBN Introduction The continuing growth o aviation increases demands on airspace capacity thereore emphasizing the need or optimum utilization o available airspace. Improved operational efficiency derived rom the application o area navigation techniques has resulted in the development o navigation applications in various regions worldwide and or all phases o flight. These applications could potentially be expanded to provide guidance or ground movement operations. Requirements or navigation applications on specific routes or within a specific airspace must be defined in a clear and concise manner. This is to ensure that the flight crew and the air traffic controllers (ATCOs) are aware o the on-board RNAV or RNP system capabilities in order to determine whether the perormance o the RNAV or RNP system is appropriate or the specific airspace requirements. RNAV and RNP systems evolved in a manner similar to conventional ground-based routes and procedures. A specific RNAV or RNP system was identified and its perormance was evaluated through a combination o analysis and flight testing. For domestic operations, the initial systems used VOR and DME or estimating their position; or oceanic operations, INS were employed. These “new” systems were developed, evaluated and certified. Airspace and obstacle clearance criteria were developed based on the perormance o available equipment; and specifications or requirements were based on available capabilities. In some cases, it was necessary to identiy the individual models o equipment that could be operated within the airspace concerned. Such prescriptive requirements resulted in delays to the introduction o new RNAV and RNP system capabilities and higher costs or maintaining appropriate certification. To avoid such prescriptive specifications o requirements, this manual introduces an alternative method or defining equipage requirements by speciying the perormance requirements. This is termed Perormance-based Navigation (PBN).
Performance-based Navigation (PBN) The PBN concept specifies that aircraf RNAV and RNP system perormance requirements be defined in terms o the accuracy, integrity, continuity and unctionality, which are needed or the proposed operations in the context o a particular airspace concept.
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The PBN concept represents a shif rom sensor-based to PBN. Perormance requirements are identified in navigation specifications, which also identiy the choice o navigation sensors and equipment that may be used to meet the perormance requirements. These navigation specifications are defined at a sufficient level o detail to acilitate global harmonization by providing specific implementation guidance or States and operators. Under PBN, generic navigation requirements are defined based on operational requirements. Operators then evaluate options in respect o available technology and navigation services, which could allow the requirements to be met. An operator thereby has the opportunity to select a more cost-effective option, rather than a solution being imposed as part o the operational requirements. Technology can evolve over time without requiring the operation itsel to be reviewed, as long as the expected perormance is provided by the RNAV or RNP system. As part o the uture work o ICAO, it is anticipated that other means or meeting the requirements o the navigation specifications will be evaluated and may be included in the applicable navigation specifications, as appropriate.
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Figure 19.1 PBN Concept
PBN concept; Perormance-based navigation: area navigation (RNAV) based on perormance requirements or aircraf operating along an ATS route, on an instrument approach procedure or in a designated airspace. PBN concept Shif rom sensor-based (RNP concept in accordance with ICAO RNP manual) to perormance-based navigation in accordance with ICAO Doc 9613.
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Figure 19.2 Navigation Differences
Aircraf navigate based on direct signals rom ground-based radio NAVAIDs
Aircraf compute their latitude-longitude position
Navigation relies on aircraf crossing radio beacons and tracking to and rom them directly
Navigation relies on aircraf crossing fixes defined by name, latitude and longitude
Routes are dependent on the location o the navigation beacons, resulting in longer routes.
Routes are not or less dependent on the location o NAVAIDs, resulting in much more flexible route designs.
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Performance-based Navigation (PBN) Principles The PBN concept specifies that aircraf RNAV and RNP system perormance requirements be defined in terms o: Accuracy Integrity Availability Continuity Perormance requirements are identified in navigation specifications, which also identiy the choice o navigation sensors and equipment that may be used to meet the perormance requirements. Accuracy The measure o the precision o the navigation solution. ICAO Standards and Recommended Practices (SARPS) speciy the accuracy requirements or various phases o flight. Current technology can use the GNSS constellations to meet IFR accuracy requirements or oceanic and domestic en-route use as well as terminal area and non-precision approaches. Precision approaches will require some orm o GNSS augmentation to overcome the known limitations o the constellation systems. The most common causes o reduced accuracy are: Integrity A measure o the trust that can be placed in the correctness o the inormation supplied. The parameters defining the integrity are specific to navigation specifications: Alert Limit (AL): the error tolerance not to be exceeded without issuing an alert
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• Means the region (horizontal and vertical) which is required to contain the indicated position with the required probability or a particular navigation mode
P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
• Required ALs depend on the type o operation Time to Alert: the maximum allowable time elapsed rom the onset o the navigation system being out o tolerance until the equipment enunciates the alert (LNAV = 10 seconds, LPV APP down to 200f = 6 seconds). Integrity Risk: probability that, at any moment, the position error exceeds the Alert Limit. Protection Level (PL): statistical bound error computed so as to guarantee that the probability o the absolute position error exceeding said number is smaller than or equal to the target integrity risk • Means the region (horizontal and vertical) assured to contain the indicated position. It defines the region where the missed alert requirement can be met • PLs are computed by the on board receiver
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I, during an operation the PLs exceed the required ALs, the operation cannot continue. • VPL only used or operations with vertical guidance (e.g. LPV) xAL: fixed value during operation xPL: value calculated by on-board receiver (varies depending on aircraf and satellite geometry and SBAS corrections) The integrity o the system (or service) establishes to which degree the navigation source can be trusted during the flight. Availability Percentage o time that the services o the system are usable by the navigator. (Alt: proportion o time during which reliable navigation inormation is presented to the crew, autopilot, or other system managing the flight o the aircraf) The availability o a system (or service) establishes the percentage o time during when the operation (or example a final approach) can be started. Continuity The capability o the system to perorm its unction without unscheduled interruptions during the intended operation. (Alt rom ICAO SARPS: It relates to the capability o the navigation system to provide a navigation output with the specified accuracy and integrity during the approach, assuming that it was available at the start o the operation) The continuity o the system guarantees that once an operation (or example a final approach) is initiated, it will not be interrupted. The PBN concept represents a shif rom sensor-based to PBN. 9 1
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Figure 19.3
Advantages o PBN over sensor-specific methods o developing airspace: • reduces the need to maintain sensor-specific routes and procedures, and their associated costs; • avoids the need or developing sensor-specific operations with each new evolution o navigation systems, which would be cost-prohibitive;
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Performance-based Navigation (PBN) • allows or more efficient use o airspace (route placement, uel efficiency and noise abatement); • clarifies how RNAV and RNP systems are used; and • acilitates the operational approval process or operators by providing a limited set o navigation specifications intended or global use. Computed vs raw data
Conventional navigation The navigation perormance data used to determine the separation minima or route spacing depend on the accuracy o the raw data rom specific NAVAIDs such as VOR, DME or NDB
PBN Requires an RNAV or RNP system that integrates raw navigation data to provide a positioning and navigation solution. In determining separation minima and route spacing in a PBN context, this integrated navigation perormance “output” (computed data) is used. Area navigation system will confirm the validity o the individual sensor data and, in most systems, will also confirm the consistency o the computed data beore they are used.
Components PBN is composed o 3 constituents Navigation Specification: set o aircraf and aircrew requirements needed to support a navigation application within a defined airspace concept. Navigation Inrastructure: ground based NAVAIDS or space based NAVAIDS. 1 9
Navigation Application: application o a navigation specification and the supporting NAVAID inrastructure, to routes, procedures, and/or defined airspace volume, in accordance with the intended airspace concept.
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Figure 19.4 Components
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Example – RNAV 1
RNAV 1 reers to an RNAV navigation specification which includes a requirement or 1 NM navigation accuracy (among other requirements).
In terms o navigation inrastructure, the ollowing systems enable RNAV 1: GNSS, DME/DME and DME/DME/IRS
RNAV 1 can support en-route and terminal navigation applications, like SIDs or STARs.
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Figure 19.5 Scope
For Oceanic/remote, en-route and terminal operations, PBN is limited to operations with linear lateral perormance requirements and time constraints.
For Approach operations, PBN accommodates both linear and angular laterally guided operations.
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Performance-based Navigation (PBN) Navigation Specifications, RNAV and RNP
F i g u r e 1 9 . 6 N a v i g a t i o n S p e c i fi c a t i o n s ,. R N A V a n d R N P
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Navigation Functional Requirements RNAV and RNP specifications include requirements or certain navigation unctionalities. At the basic level, these unctional requirements may include: 1.
Continuous indication o aircraf position relative to track to be displayed to the pilot flying on a navigation display situated in his primary field o view;
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Display o distance and bearing to the active (To) waypoint;
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Display o ground speed or time to the active (To) waypoint;
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Navigation data unction; and
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Appropriate ailure indication o the RNAV or RNP system, including the sensors.
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Figure 19.7 Garmin
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Performance-based Navigation (PBN) Designation of RNP and RNAV Specifications RNAV X RNP X The expression “X” means the aircraf can ollow a pre-defined track (lateral navigation) with X Nautical Miles (NM) accuracy 95% o the flight time by the population o aircraf operating within the airspace, route or procedure.
Figure 19.8
Navigation systems are specified in terms o Navigation System Error (NSE), and thereore hypotheses on the Flight Technical Error (FTE) and Path Definition Error (PDE) contributions to the Total System Error (TSE) are made to qualiy a system or a given navigation specification. Path Definition Error (PDE): occurs when the path defined in the RNAV system (database) does not correspond to the desired path, i.e. the path expected to be flown over the ground. PDE is considered negligible i quality assurance process is applied at the navigation database level and i correct operating procedures are applied. 1 9
Flight Technical Error (FTE): relates to the air crew or autopilot’s ability to ollow the defined path or track.
P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Navigation System Error (NSE): reers to the difference between the aircraf’s estimated position and actual position. Because specific perormance requirements are defined or each navigation specification, an aircraf approved or a particular navigation specification is not automatically approved or any other navigation specification. Similarly, an aircraf approved or an RNP or RNAV specification having stringent accuracy requirements (e.g. RNP 0.3 specification) is not automatically approved or a navigation specification having a less stringent accuracy requirement (e.g. RNP 4).
Figure 19.9
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RNAV 10 Oceanic / remote phases o flight Without on-board perormance monitoring and alerting unction, even when operationally approved as “RNP 10” Lateral TSE must be within ±10 NM or at least 95 per cent o the total flight time 50NM lateral and 50NM longitudinal separation Based on at least two independent LRNS comprising an INS, IRS FMS or a GNSS Dual INS/IRS are time limited which may be extended by updating.
RNP 4 Oceanic / remote phases o flight With on-board perormance monitoring and alerting unction (usually RAIM) Lateral TSE must be within ±4 NM or at least 95 per cent o the total flight time 30 NM lateral and 30 NM longitudinal separation Primarily based on GNSS. At least two LRNSs, capable o navigating to RNP4 and listed in the flight manual, must be operational at the entry point o the RNP airspace.
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RNAV 5*
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En-route and arrival** phases o flight Without on-board perormance monitoring and alerting unction Lateral TSE must be within ±5 NM or at least 95 per cent o the total flight time Route spacing may vary among regional implementations Based on VOR/DME, DME/DME, INR, IRS or GNSS . Manual data entry acceptable. * Almost equivalent to Basic RNAV (B-RNAV) within ECAC (European Civil Aviation Conerence). ** May be used or the initial part o a STAR outside 30 NM and above MSA.
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RNAV 2 En-route continental, arrival and departure phases o flight Without on-board perormance monitoring and alerting unction Lateral TSE must be within ±2 NM or at least 95 per cent o the total flight time Based on DME/DME, DME/DME/IRU and GNSS Pilots must not fly a SID or STAR unless it is retrievable by route name rom the onboard navigation database and conorms to the charted route Route may be modified through the insertion (rom database) or deletion o waypoints Manual entry is not permitted
RNP 2 Oceanic, continental, en-route and airspaces considered to be remote With on-board perormance monitoring and alerting unction (usually RAIM) Lateral TSE must be within ±2 NM or at least 95 per cent o the total flight time Based on GNSS Pilots must not fly a SID or STAR unless it is retrievable by route name rom the onboard navigation database and conorms to the charted route Route may be modified through the insertion (rom database) or deletion o waypoints Manual entry is not permitted 1 9
P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
RNAV 1* Arrival and departure phases o flight Without on-board perormance monitoring and alerting unction Lateral TSE must be within ±1 NM or at least 95 per cent o the total flight time Based on DME/DME, DME/DME/IRU and GNSS *Almost equivalent to Precision RNAV (P-RNAV) within ECAC Pilots must not fly a SID or STAR unless it is retrievable by route name rom the onboard navigation database and conorms to the charted route Route may be modified through the insertion (rom database) or deletion o waypoints Manual entry is not permitted
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RNP 1 Arrival and departure phases o flight With on-board perormance monitoring and alerting unction (usually RAIM) Lateral TSE must be within ±1 NM or at least 95 per cent o the total flight time For terminal airspace with no or limited ATS surveillance, with low to medium density traffic Based on GNSS Pilots must not fly a SID or STAR unless it is retrievable by route name rom the onboard navigation database and conorms to the charted route Route may be modified through the insertion (rom database) or deletion o waypoints Manual entry is not permitted
RNP APCH Approach phase o flight With on-board perormance monitoring and alerting unction (usually RAIM or SBAS) Lateral TSE varies with minima and approach segment (initial, intermediate, final, missed) Based on: GNSS or LNAV minimum GNSS + barometric VNAV or LNAV/VNAV minimum* GNSS augmented by SBAS or LP and LPV minima
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*GNSS-based vertical guidance may be used i certified or the purpose.
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Pilots must not fly a SID or STAR unless it is retrievable by route name rom the onboard navigation database and conorms to the charted route RNP APCH to LNAV minima is a non-precision instrument approach procedure designed or 2D approach operations LPV Final Approach Segment is specially coded into a Data Block inside the on-board navigation database. It is known as the FAS DB RNP APCH to LPV minima requires a FAS data-block
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Performance-based Navigation (PBN)
RNP AR (Authorisation Required) Approach phase o flight With on-board perormance monitoring and alerting unction (usually RAIM) Cross-track error must be lower than the lateral applicable accuracy value or 95 per cent o flight time For terminal airspace with no or limited ATS surveillance, with low to medium density traffic Based on GNSS + (usually) barometric-based VNAV
Authorization Required (AR) – Increased risk, advanced aircraf capabilities and increase d aircrew training. Containment area is 2 x RNP. Thereore, RNP 0.1 = 0.2NM (370 metres)
RNP 0.3 All phases o flight except oceanic/remote and final approach With on-board perormance monitoring and alerting unction (usually RAIM or SBAS) Lateral TSE must be within ±0.3 NM or at least 95 per cent o the total flight time Primarily or helicopters Based on GNSS
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Use of PBN
P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Generic navigation requirements are defined based on operational needs. Operators then evaluate options in respect o available technology and navigation services. PBN brings the opportunity to select cost-effective options.
Airspace Planning PBN is one o several enablers o an airspace concept. Communications, ATS surveillance and Air Traffic Management are also essential elements o an airspace concept. The determination o separation minima and route spacing* or use by aircraf is a major element o airspace planning Manual on Airspace Planning Methodology or the Determination o separation Minima (Doc 9689) Manual on the Use o Perormance-Based Navigation (PBN) in Airspace Design (Doc 9992)
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Figure 19.10
Separation minima and route spacing can generally be described as being a unction o three actors:
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Figure 19.11
Approval The airworthiness approval process assures that each item o the area navigation equipment installed is o a type and design appropriate to its intended unction and that the installation unctions properly under oreseeable operating conditions. Accuracy, integrity, continuity, unctional requirements, on-board perormance monitoring and alerting, navigation database, path terminators…
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Performance-based Navigation (PBN) It also details: Limitations Other relevant inormation Some PBN specifications require (and will require) operational approval, including: RNP APCH, as detailed in AMC 20-27 and AMC 20-28. Requirement or operational approval will be removed once NPA 2013-25 is adopted. RNP AR APCH, as detailed in AMC 20-26 Advanced RNP: to be developed The RNAV system shall enable the crew to navigate in accordance with operational criteria as defined in the Navigation Specification The State o the Operator is the authority responsible or approving flight operations
Specific RNAV and RNP System Functions The standard that fixes database ormats and contents is the ARINC 424 ‘Navigation System Data Base Standard.’ Area Navigation (RNAV) involves flying between waypoints not coinciding with ground fixes.
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P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Figure 19.12
Waypoints coordinates are hence loaded in the on-board aircraf’s database. Types: Fly-by: the navigation system anticipates the turn onto the next leg. Fly-over: the aircraf overflies the waypoint beore starting the turn onto the next route leg. ARINC 424 also defines the Path Terminator: permits defining how to navigate to, rom and between waypoints. The Path Terminator is a two-letter code, which defines a specific type o flight path along a segment o a procedure and a specific type o termination o that flight path
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Performance -based Navigation (PBN)
19
Path terminators are assigned to all RNAV SID, STAR and approach procedure segments in an airborne navigation database This allows translating into computer language (FMS) the procedures designed or clock & compass manual flight Charted procedures are translated into a sequence o ARINC 424 legs in the database There are 23 different path terminators defined in ARINC 424. Those which can be expected in RNAV or RNP charts are depicted on Figure 19.13.
Fixed Radius Paths There are two types o FIXED RADIUS PATHS Radius to Fix (RF)
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) N B P ( n o i t a g i v a N d e s a B e c n a m r o f r e P
Figure 19.13
Is also a type o Path Terminator Specific curved path radius in a terminal or approach procedure Is defined by radius, arc length, and fix
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Performance-based Navigation (PBN) Fixed radius transition (FRT) To be used* with en-route procedures It alls upon the RNP system to create it between two route segments These turns have two possible radii, 22.5 NM or high altitude routes (above FL 195) and 15 NM or low altitude routes. Using such path elements in an RNAV ATS route enables improvement in airspace usage through closely spaced parallel routes * The “Concept o Use” o FRT is currently being evaluated by ICAO, who is careully Figure 19.14 addressing promulgation, airspace design and avionics capabilities aspects, among others. No State has published yet any ATS Routes that require the FRT unction.
FB/FO Path Terminators Fixed Radius Paths Off/Hold Many aircraf have the capability to fly a path parallel to, but offset lef or right rom, the original active route.
Offset Flight Path The purpose o this unction is to enable offsets or tactical operations authorized by ATC. Capability or the flight crew to speciy a lateral offset rom a defined route (generally in increments o 1NM to 20 NM)
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P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Figure 19.15
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Performance -based Navigation (PBN)
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Many aircraf have the capability to execute a holding pattern manoeuvre using their RNAV system, which can provide flexibility to ATC in designing RNAV operations. The RNAV system acilitates the holding pattern specification by allowing the definition o the inbound course to the holding waypoint, turn direction and leg time or distance on the straight segments, as well as the ability to plan the exit rom the hold.
Figure 19.16
Data Processes All RNAV and RNP applications use aeronautical data to define, inter alia, ground-based NAVAIDs, runways, gates, waypoints and the route/procedure to be flown. The saety o the application is contingent upon the accuracy, resolution and integrity o the data. Thereore: 9 1
The accuracy o the data depends upon the processes applied during the data origination.
) N B P ( n o i t a g i v a N d e s a B e c n a m r o f r e P
The integrity o the data depends upon the entire aeronautical data chain rom the point o origin to the point o use.
PBN Operations What pilots need to know about PBN operations is whether the aircraf and flight crew are qualified to operate in the airspace, on a procedure or along an ATS route. The flight operations element considers: The operator’s inrastructure or conducting PBN operations and flight crew operating procedures, training and competency demonstrations. The operator’s MEL, OMs, checklists, navigation database validation procedures, etc. There are 3 main independent lateral errors in the context o on-board perormance monitoring and alerting. Together they account or the Total System Error (TSE). Path Definition Error (PDE): occurs when the path defined in the RNAV system (database) does not correspond to the desired path, i.e. the path expected to be flown over the ground . 25
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Performance-based Navigation (PBN) Flight Technical Error (FTE): relates to the air crew or autopilot’s ability to ollow the defined path or track Navigation System Error (NSE): reers to the difference between the aircraf’s estimated position and actual position
Figure 19.17
On-board Performance Monitoring And Alerting This unction allows the air crew to detect whether or not the RNP system satisfies the navigation perormance required in the navigation specification. Relates to both lateral and longitudinal navigation perormance On-board means that the perormance monitoring and alerting is effected on board the aircraf and not elsewhere.
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Monitoring reers to the monitoring o the aircraf’s perormance with regard to its ability to determine positioning error and/or to ollow the desired path.
P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Alerting relates to monitoring: i the aircraf’s navigation system does not perorm well enough, this will be alerted to the air crew. RAIM (Receiver Autonomous Integrity Monitoring) - a orm o ABAS. The GPS ground stations monitor GPS satellites and detect aults. It can take too much time to detect a ault and update the navigation messages sent to the users to declare a particular satellite Signal in Space (SIS) erroneous. To solve this, GPS receivers have an autonomous way o assuring the integrity o GPS pseudo-ranges: the RAIM algorithm. GPS receivers require a minimum set o 4 satellites to compute a 3D position. With additional satellites, the “RAIM algorithm” comes into play. A 5th satellite provides Fault Detection (FD) capability: the receiver recognises a aulty satellite, but is not able to identiy which one in particular. A 6th satellite provides Fault Detection and Exclusion (FDE) capability: the receiver is able to isolate the aulty satellite. RAIM prediction is required beore conducting a flight which will use a GPS approach. This prediction can be used using the GPS receiver or with an
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Performance -based Navigation (PBN)
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internet-based RAIM prediction tool. During flight, the receiver’s RAIM (FD or FDE) algorithm monitors the position. Approach will be discontinued i ault detection detects a position ailure when integrity is provided by FDE. LPV is based on SBAS integrity; i RAIM is unavailable the approach can be perormed anyway.
Figure 19.18
On-board perormance monitoring shall not be regarded as error monitoring. Alerts are issued when the system cannot guarantee with sufficient integrity that the position meets the accuracy requirement. 9 1
When an alert is issued, the probable reason is the loss o capability to validate the position data (insufficient satellites being a potential reason).
) N B P ( n o i t a g i v a N d e s a B e c n a m r o f r e P
Abnormal Situations Abnormal and contingency procedures are to be used in case o the loss o PBN capability. Abnormal procedures should be available to address cautions and warnings resulting rom the ollowing conditions: 1.
Failure o the navigation system components including those affecting flight technical error (e.g. ailures o the flight director or auto pilot);
2.
RAIM alert or loss o integrity unction;
3.
Warning flag or equivalent indicator on the lateral and/or vertical navigation display;
4.
Degradation o the GNSS approach mode during a LPV approach procedure (e.g. downgrade rom LPV to LNAV);
5.
Low altitude alert (i applicable)
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Performance-based Navigation (PBN) LPV to LNAV reversion: 1.
For LPV approaches, some systems allow LPV to LNAV reversion i the vertical signal is lost or degraded.
2.
I LPV to LNAV reversion takes place beore the FAF/FAP, the crew can envisage continuing with the approach to the LNAV minima.
3.
I reversion occurs afer the FAF/FAP, go-around is required, unless the pilot has in sight the visual reerences required to continue the approach.
In case o a complete RNAV guidance loss during the approach, the crew must ollow the operator defined contingency procedure/s. In the event o communications ailure: a) Flight crew should continue with the 2D/3D RNAV(GNSS) procedure in accordance with published lost communication procedures; or b)
Follow procedures stated in the chart;
The flight crew should react to TAWS warnings in accordance with approved procedures. The flight crew should notiy ATC o any problem with the navigation system that results in the loss o the approach capability.
Database Management The navigation database must contain all the necessary data/inormation to fly the published approach procedure. Thereore, the on-board navigation data must be valid or the current Aeronautical Inormation Regulation and Control (AIRAC) cycle and must include the appropriate flight procedures. The operator should implement procedures that ensure timely distribution and insertion o current and unaltered electronic navigation data to all aircraf that require it.
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P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Unless otherwise specified in operations documentation or AMC the navigation d/b must be valid.
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Performance -based Navigation (PBN)
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Requirements for Specific RNAV And RNP Specifications
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) N B P ( n o i t a g i v a N d e s a B e c n a m r o f r e P
Figure 19.19
RNP APCH LNAV minima - Non Precision Approach 2D operation Linear lateral guidance based on GNSS Expected to be flown using the continuous descent final approach (CDFA) technique
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Performance-based Navigation (PBN) Integrity provided by RAIM, unless SBAS is available LP minima Non Precision Approach 2D operation Angular lateral guidance based on GNSS augmented by SBAS Expected to be flown using CDFA technique Integrity provided by SBAS Not published at runways with LPV minima LNAV/VNAV minima - Approach with Vertical guidance (APV) 3D operation Linear lateral guidance based on GNSS Linear vertical guidance based on BaroVNAV (can also be supported by SBAS and, in any case, the used angular vertical guidance must be certified or the purpose) Integrity provided by RAIM, unless SBAS is available
LNAV/VNAV minima
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P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Figure 19.20
LPV minima - Approach with Vertical guidance (APV) 3D operation Angular lateral and vertical guidance based on GNSS augmented by SBAS
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Performance -based Navigation (PBN)
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Integrity provided by SBAS LPV Final Approach Segment is specially coded into a Data Block inside the on-board navigation database. It is known as the FAS DB. VPA – Vertical Path Angle. LPV minima FAS DB “The set o parameters to identiy a single precision approach or APV and define its associated approach path” (ICAO)” Is part o the data package o an APV SBAS procedure: The FAS-DB contain the parameters that define the Final Approach Segment geometry The integrity o the data in ensured by the generation o a CRC algorithm (Cyclic redundancy check) LPV minima FAS DB: why? To ensure the integrity o databases In ILS/MLS approaches, integrity is ensured by: Proper alignment o transmitting antennas Flight checks Integrity monitors on the transmitted signal LPV approaches: A kind o approach based on on-board data Integrity rests on the data describing the approach path Hence the importance o having a CRC wrapping the FAS DB
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) N B P ( n o i t a g i v a N d e s a B e c n a m r o f r e P
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Performance-based Navigation (PBN)
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P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
Figure 19.21
In terms o phraseology, no distinction is made between the different types o RNAV (GNSS) approaches (no distinction according to LPV, LNAV/VNAV and LNAV minima) The minima to which the procedure is flown is unknown to Air Traffic Controllers
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Performance -based Navigation (PBN)
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Most RNAV (GNSS) final approach procedures leading to LNAV, LNAV/VNAV or LPV minima, may be preceded by either an initial and intermediate T-bar or Y-bar approach. In this case all segments are published on the same chart. A T- or Y-bar arrangement permits direct entry to the procedure rom any direction, provided entry is made rom within the capture region associated with an IAF. Where one or both offset IAFs are not provided, a direct entry will not be available rom all directions. In such cases a holding pattern may be provided at the IAF to enable entry to the procedure via a procedure turn. Sometimes may be preceded by an initial and intermediate RNAV 1 approach (generally preceded by a RNAV 1 STAR) or by radar guidance
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) N B P ( n o i t a g i v a N d e s a B e c n a m r o f r e P
Figure 19.22
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Performance-based Navigation (PBN) A RNP APCH shall not be flown unless it is retrievable by procedure name rom the on-board navigation database and conorms to the charted procedure Retrieving a procedure rom the database: By name: usually IAF I LPV is available, also by SBAS Channel Number, which is a unique worldwide identifier composed o 5 numeric characters, in the range o 40000 to 99999 Example GRAZ RNAV (GNSS) RWY 35 3 IAFs: WG832, WG834 and WG833 1 Channel Number: 48472 Pilot can select one o the 4 previous options. Selecting the channel number will load an ‘extended’ Final Approach Segment, as an ILS. In this later case, pilot is expected to intercept the extended FAS ollowing ATC Vectors To Final ‘Direct to’ waypoints ollowing ATC clearances are allowed except or FAP
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P e r f o r m a n c e B a s e d N a v i g a t i o n ( P B N )
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Performance -based Navigation (PBN)
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) N B P ( n o i t a g i v a N d e s a B e c n a m r o f r e P
Figure 19.23
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Questions Questions 1.
Which o the ollowing is a 2D approach? a. b. c. d.
2.
Which o the ollowing is a 3D approach? a. b. c. d.
3.
Q u e s t i o n s
6.
5nm o the desired path at least 95% o the time 5nm o their displayed position at least 95% o the time 5km o their displayed position at least 95% o the time 5nm o the desired path at least 99% o the time
ILS NDB GNSS RADAR
Which o the ollowing may be used in the approach phase o flight? a. b. c. d.
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Within Within Within Within
Which o the ollowing sources may be used or RNAV compliance? a. b. c. d.
7.
SRA RNP APCH RNP AR APCH RNAV1
For the RNAV 5 specification, the population o aircraf operating within the airspace, route, or procedure are expected to be: a. b. c. d.
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SBAS Dual GNSS sensors BaroVNAV DME
Which o the ollowing requires specific authorisation? a. b. c. d.
5.
LNAV VOR/DME LPV SRA
Which o the ollowing may be required or a LNAV/VNAV approach (Select 2)? a. b. c. d.
4.
ILS LPV LNAV LNAV/VNAV
RNAV1 RNP APCH RNP4 P-RNAV
Questions 8.
What does the ollowing symbol depict? a. b. c. d.
9.
d.
The trust that can be placed in the navigation solution The ability o the system to present usable inormation to the operator The measure o the precision o the navigation solution The ability o the system to perorm its unction without interruption
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s n o i t s e u Q
PBN consists o three elements. They are; a. b. c. d.
14.
6 seconds 10 seconds 15 minutes 15 seconds
In terms o PBN, Accuracy is defined as; a. b. c. d.
13.
To overlay an NDB approach contained within a current equipment database To fly a RNAV or RNP approach contained within the equipment’s database To fly a published terminal NDB hold when the aircraf is not equipped with ADF To fly the final approach track o an ILS
The Time to Alert (TTA) or a LPV Approach is; a. b. c. d.
12.
A waypoint which may be flown by A VOR/DME installation A waypoint which must be flown over The Initial Approach Fix
Under which o the ollowing circumstances may GNSS be used as a means o primary navigation? a. b. c.
11.
A waypoint which must be flown over A waypoint which may be flown by The Final Approach Fix A VOR installation
What does the ollowing symbol depict? a. b. c. d.
10.
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Navigation Application, Specification and Inrastructure RNAV, RNP and Beacon Hopping Ground, Space and Control Space, User and Control
PBN accommodates both linear and angular laterally guided operations; a. b. c. d.
For en-route operations For Approach operations For Approach and en-route operations For RNP 0.1 Approaches only
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Answers
15.
RNP 1 is based on; a. b. c. d.
16.
PBN Navigational unctional requirements include; a. b. c. d.
17.
A n s w e r s
20.
Final Approach Segment Database Full Auto System Data Block Final Approach Segment Data Block Flight Approach System Database
The PBN Airspace Concept consists o; a. b. c. d.
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RNAV and RNP applications use the data to define procedures to be flown They determine the ILS decision height The accuracy needs to be checked against the VOR/NDB The processes used to define RNP routes can be used without an up to date Navigation Database
What is meant by the term FAS DB? a. b. c. d.
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Radius to Fix and Fixed Radius Transition Offset flight path and Fixed Radius Transition RNAV Offset flight path and RNP Offset flight path Hold and Path terminators
Data processes applied in PBN are critical to saety because; a. b. c. d.
19.
Aircraf position relative to track and distance and bearing to the active waypoint On-board perormance monitoring and alerting unction A requirement that TSE is bounded at zero At least two LRNS, one o which must be GNSS
There are two types o Fixed Radius Paths. Namely; a. b. c. d.
18.
VOR/DME and does not require on-board perormance and monitoring IRS and is used or oceanic/continental airspace NDB and requires on-board perormance and monitoring GNSS and requires on-board perormance and monitoring
COM, NAV, SUR and ATM En-route, Oceanic and Terminal LNAV, VNAV and LPV VOR, DME and GNSS
Questions
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s n o i t s e u Q
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