3PBN TF/5 – WP/05
Revision 1
PBN TF/5– WP/05
Revision 1
28/07/2011
EANPG PROGRAMME COORDINATING GROUP (COG)
PERFORMANCE BASED NAVIGATION IMPLEMENTATION TASKFORCE
(PBN TF)
FIFTHMEETING
(Paris, France, 23-24 May 2011)
Draft Guidance Materialfor the Implementation of RNP APCH Operations
(Updated After PBN TF 05)
(Presented by Rick Farnworth - EUROCONTROL)
SUMMARYThis working paper presents the updated draft of guidance material developed by EUROCONTROL to support States in the implementation of RNP APCH operations. It is presented here as an input to ICAO discussions and as a contribution to the development of ICAO Guidance material.
This version has been updated taking into account comments received from the 5th meeting of the ICAO PBN Implementation Task Force and APV Workshop held in May 2011.
Table of Contents
1.Introduction
2.Glossary of The Main Terms......
3.PART A – INTRODUCTION TO RNP APCH OPERATIONS
3.1.Background Information
3.2.Approaches with vertical guidance (APV)
3.3.Approaches and the PBN concept
3.4.Provision of vertical guidance
3.5.Applicable Standards and Documentation
4.PART B – GUIDANCE ON THE IMPLEMENTATION OF RNP APCH
4.1.General
4.2.Process 1: Agreeing the operational requirement and building the implementation plan
4.2.1.General
4.2.2.Activity 1: The background to RNP APCH implementation
4.2.3.Activity 2: Create the implementation project team
4.2.4.Activity 3: Agree project objectives, scope and timescale
4.2.5.Activity 4: Survey of candidate airports
4.2.6.Activity 5: Assessment of Airport Capabilities
4.2.6.1.General
4.2.6.2.Aerodrome infrastructure assessment
4.2.6.3.Meteorological data
4.2.6.4.GNSS infrastructure
4.2.6.5.Other infrastructure
4.2.6.6.Achievable minima estimation
4.2.6.7.Integration of the new procedure into the terminal area
4.2.7.Activity 6: Survey of Traffic Characteristics and Aircraft Operators
4.2.7.1.Survey of traffic characteristics
4.2.7.2.Survey of Aircraft Operators
4.2.8.Activity 7: ATC and AIS services
4.2.9.Activity 8: Benefits and costs for RNP APCH implementation
4.2.9.1.Benefits
4.2.9.2.Costs
4.2.10.Activity 9: Choose which type of RNP APCH to implement
4.3.B-III Process 2: RNP APCH implementation
4.3.1.General
4.3.2.Activity 10: Procedure design
4.3.3.Activity 11: Validation of expected benefits
4.3.4.Activity 12: Local Safety Case
4.3.5.Gate :Final decision to implement
4.3.6.Activity 13: Procedure validation
4.3.7.Activity 14: ATM/CNS Integration Issues
4.3.8.Activity 15: AIS Requirements
4.3.8.1.Approach publication
4.3.8.2.AIC and AIP publication
4.3.9.Activity 16: Training Requirements
4.3.10.Activity 17: Final Review before implementation
4.3.11.Activity 18: Introduction into service
4.3.12.Activity 19: Post-implementation activities
1.Introduction
1.1.ICAO is encouraging all States to implement RNP APCH procedures and requesting the publication of a PBN Implementation Plan through the ICAO Assembly Resolutions 36-23 and 37-11. This document has been developed in response to an increasing need for guidance on RNP APCH implementation that has been expressed in several forums.
1.2.This guidance is primarily intended for States in the ICAO European region who wish to implement RNP APCH operations. It describes the generic steps that an ANSP and/or Airport should undertake to introduce such operations together with the applicable standards and relevant documentation that is available. The guidance also addresses aircraft operators by including an overview of the available standards that can be used to obtain airworthiness certification and operational approval.
1.3.RNP AR APCH procedures are outside the scope of this document.
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2.Glossary of The Main Terms
2.1.APV – Approach Procedures with Vertical Guidance. This term is used for RNP APCH operations that include vertical guidance, they are flown to LNAV/VNAV or LPV minima.
2.2.APV Baro – RNP APCH down to LNAV/VNAV minima
2.3.APV SBAS – RNP APCH down to LPV minima
2.4.Baro-VNAV – an onboard functionality where the barometric altimeter is a part of an integrated Air Data System connected to the Flight Management Computer. It computes vertical guidance relative to a computed profile.
2.5.CDFA –CDFA is a technique for flying the final approach segment of an NPA as a continuous descent. The technique is consistent with stabilized approach procedures and has no level-off. A CDFA starts from an altitude/height at or above the FAF and proceeds to an altitude/height approximately 50 feet (15 meters) above the landing runway threshold or to a point where the flare manoeuvre should begin for the type of aircraft being flown. This definition is harmonized with the ICAO and the European Aviation Safety Agency (EASA).
2.6.DA/H– Decision Altitude/Height, used in Precision and APV Approaches
2.7.EGNOS – The European Geostationary Navigation Overlay Service. This is the European Satellite Based Augmentation System (SBAS).
2.8.ESSP –European Satellite Services Provider is the EGNOS operator and Navigation Service Provider certified according to the SES regulation as an ANSP.
2.9.GNSS – Global Navigation Satellite System. GNSS is a generic term for all satellite navigation systems and their augmentations. GNSS includes GPS, ABAS, SBAS, GBAS, Galileo, Glonass, Compass
2.10.GPS NPA – An RNP APCH flown to LNAV minima. The term is also used in the ICAO classification of approaches.
2.11.LNAV, LNAV/VNAV, LPV and LP are the minima lines on the chart. The minima line to be used depends on the aircraft capability and approval.
2.12.LNAV – Lateral Navigation. The minima line on the chart for RNP Approaches without vertical guidance.
2.13.LNAV/VNAV – the minima line to be flown if the aircraft has a Baro-VNAV system approved according to AMC 20-27 or equivalent (for example FAA AC 20-129).
2.14.LPV – the minima line to be flown if the aircraft has SBAS capability approved according to AMC 20-28 or equivalent.
2.15.LP – Localizer Performance, the minima line to be flown by SBAS-capable aircraft where, due to obstacles, terrain, airport infrastructure limitations or SBAS coverage area, an approach with vertical guidance (down to LPV) is not possible.
2.16.MDA/H– Minimum Descent Altitude/Height, used in a Non-precision Approach
2.17.NPA – Non-Precision Approach
2.18.PBN – Performance-Based Navigation. The PBN concept specifies Navigation Specifications in terms of navigation system performance accuracy, integrity, availability and continuity along with the functionality required onboard an aircraft for the proposed operations
2.19.RNP APCH – This is the terminology used in the ICAO PBN Manual [1] to describe the four approach types shown in Figure 1. Note that all these procedures are published on a chart with the title RNAV(GNSS).
Figure 1: The four types of RNP APCH described in the ICAO PBN Manual
2.20.RNAV Approach – This is a generic name for any kind of approach that is designed to be flown using the onboard area navigation system. It uses waypoints to describe the path to be flown instead of headings and radials to ground-based navigation aids. RNP APCH operations are types of RNAV approach.
2.21.RNPAR APCH– An approach which always requires specific operational approval (SPA). Such procedures are useful in particular environments rich in terrain.
2.22.RNAV – Area Navigation
2.23.RNP – Required Navigation Performance
2.24.SBAS – Satellite-Based Augmentation System. This is a generic name for a system based on geostationary satellites and accompanying ground stations used for the augmentation of GNSS signals. The European SBAS is called EGNOS, the US version is called WAAS and there are also other SBAS in different regions of the World.
2.25.SPA – Specific operational approval required by EU-OPS, EASA-OPS or State rules on air operations for certain types of instrument navigation operations.
2.26.VNAV – Vertical Navigation
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3.Applicable Standards and Documentation
- ICAO, Performance-Based Navigation Manual, Volume II, Implementing RNAV and RNP (Doc 9613)
- ICAO State Letter SP 65/4-10/53, Guidance material for the issuance of required navigation performance approach (RNP APCH) operational approval (23rd July 2010)
- ICAO Assembly Resolutions A37-11 and A36-23
- EUROCONTROL ESSIP Objectives, NAV10 in for period 2011-2015
- ICAO Annex 14 – Aerodromes
- Consistency of current ICAO material (Annexes and Manual) vs. APV operations (presented by France at ICAO NSP 2010, WGW/WP64)
- EU OPS 1 Subpart E All Weather Operations (EU OPS 1.430 Aerodrome Operating Minima, (d) Determination of RVR / CMV / Visibility Minima for Category I, APV and Non-Precision Approach operations, table 5)
- ICAO, Doc 4444, Procedures for Air Navigation Services, Rules of the Air and Air Traffic Services (PANS-ATM)
- EUROCONTROL MET Tool,
- RNAV Approach Benefits Analysis V2.1, May 2009. Produced by Helios for EUROCONTROL.
- ICAO, Doc 8168, Procedures for Air Navigation Services – Aircraft Operations (PANS OPS)
- ICAO Annex 4 – Charting
- ICAO Doc 9906 – Quality Assurance Manual for Procedure Design
- ICAO Annex 15 – Aeronautical Information Service
- ICAO Doc 9635 Manual of All Weather Operations
- EUROCONTROL Tool for FAS DB
- EUROCONTROL Tool for GPS outage prediction Augur,
- RNP APCH with Baro VNAV,Safety Assessment Report, Eurocontrol 2010.
- EUROCONTROL Airspace Concept Handbook for the Implementation of Performance Based Navigation (PBN) Edition 2.0
- EGNOS Safety of Life Service Definition Document (EGNOS SoL SDD), 2nd March 2011,
21. EASA AMC 20-27 Airworthiness Approval and Operational Criteria for RNP APPROACH (RNP APCH) Operations Including APV Baro-VNAV Operations
22. EASA AMC 20-28 Airworthiness Approval and Operational Criteria for RNP APPROACH (RNP APCH) Operationto LPV minima using SBAS
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PBN TF5 WP05 RNP APCH Draft Guidance
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4.PART A – INTRODUCTION TO RNP APCH OPERATIONS
4.1.Background Information
4.1.1.The widespread availability of high-performance RNAV systems on all types of aircraft and in particular the introduction of GNSS has made it possible to use RNAV in the approach phase of flight. Safety is improved by providing pilots with better situational awareness than on conventional Non-Precision Approaches (NPA), thereby reducing the risk of controlled flight into terrain (CFIT). Better access can also be provided to runways that are not equipped with precision approach and landing systems.
This guidance material is mainly intended for States in the ICAO European Region who wish to implement RNP APCH operations. It describes the steps that an ANSP and/or Airport should undertake to implement such operations and indicates the applicable standards and relevant documentation that is available.Finally, it provides guidance to air operators as to how to obtain approval for such operations.
4.1.2.Instrument Approach Procedures
Traditionally, there have been two types of Instrument Approach Procedures:
- Precision Approaches (PA) use an instrument landing system (e.g. ILS, GBAS, MLS) which provides both lateral and vertical guidance on a geometrically defined continuous descent path.
- Non-Precision Approaches (NPA) use conventional navigation aids (e.g. NDB, VOR, DME) or basic GNSS (e.g. GPS NPA) to bring the aircraft to a point where the runway is in view and a visual landing can be performed.
4.1.3.Studies have shown that the risk of controlled flight into terrain (CFIT) on non-precision approaches could be significantly reduced. An improvement that gives pilots better situational awareness on NPA is to fly them using the RNAV capability of the aircraft. The RNAV system can be used not just for en-route and terminal area but also for approach, where RNAV approach procedures are described by a series of waypoints, legs, altitude and speed constraints stored in the onboard navigation database.
4.1.4.GNSS-based RNAV capabilities were initially used to fly NPA procedures, called GPS NPA. These procedures are flown to a Minimum Descent Altitude/Height (MDA/H), as with conventional NPAs, which is indicated as the LNAV minima line on the chart.Although the term GNSS is used throughout this document, all RNAV approaches are currently based on GPS.
4.1.5.No modifications to the cockpit instruments (e.g. conventional Course Deviation Indicator – CDI, or electronic displays) are in principle necessary to implement RNP APCH on-board.
4.1.6.The step-down descent technique for flying NPAs, which is prone to error, can also be removed. Operators are being encouraged to fly these procedures using the Continuous Descent Final Approach (CDFA) flying technique where a continuous descent vertical path is followed. This can be based on a manual calculation of the required rate of descent or it can make use of the VNAV guidance function that is available on many aircraft.The design of a Non Precision approach is made according to a single set of design criteria in ICAO PANS-OPS and is not dependent on the flying technique. Charts include the nominal descent angle. Achievable minima might be different depending on the flying technique usedto fly the final approach. The minima are calculated in accordance with Appendix 1 (New) of EU OPS 1.430. As CDFA is the recommended technique, the document provides values to be added to RVR minima in case CDFA is not used.
4.2.Approaches with vertical guidance (APV)
4.2.1.In addition to lateral RNAV capabilities, modern multi-sensor RNAV systems provide a VNAV function which allows a vertical path to be flown with a constant rate of descent. Provision of both lateral and vertical guidance may also be based on LPV capability of an aircraft.
4.2.2.RNAV approaches using both lateral and vertical guidance were defined by ICAO in Annex 6 as Approach Procedures with vertical guidance (APV).
4.2.3.The RNAV procedures using Barometric VNAV for vertical guidance are called APV Baro and are flown to a Decision Altitude/Height indicated in the LNAV/VNAV minima line on the chart.Aircraft equipped with SBAS systems can also fly procedures designed for APV Baro if the State publishing the procedure permits it.
4.2.4.The RNAV procedures using SBAS for vertical guidance are called APV SBAS procedures and are flown to the LPV minima line on the chart.
4.3.Approaches and the PBN concept
4.3.1.ICAO’s PBN concept was published in the ICAO PBN Manual (Doc 9613) in 2007 replacing the previous RNP Concept and RNP Manual. The PBN Concept aims to streamline RNAV and RNP applications on a global basis by reducing the number of navigation specifications in use worldwide and thus enhancing safety, improving interoperability and reducing costs for operators. To these ends, the PBN manual includes a limited set of PBN specifications for worldwide use in different phases of flight.
4.3.2.For final approach, the ICAO PBN Manual specifies RNP APCH navigation specifications which are to be found on PBN, Volume II, Part C, Chapter 5 [1].
4.3.3.RNP APCH procedures are published on charts with the title RNAV(GNSS) RWY XX. That is the reason why they are referred to as RNAV approaches. These approach charts can have several minima lines depending on the type of RNP APCH operation to be flown. The table below provides cross reference between RNAV and PBN terminology.
Table 1: RNP APCH terminology as per PBN Manual - ICAOState Letter [2]
RNAV world / PBN Terminology / Chart Minima / SensorGPS NPA / RNP APCH down to / LNAV (MDA) / GNSS
APV Baro / RNP APCH down to / LNAV/VNAV (DA) / GNSS + Baro-VNAV
- / RNP APCH down to / LP (MDA) / GNSS+SBAS
APV SBAS / RNP APCH down to / LPV (DA) / GNSS+SBAS
4.3.4.An example of an RNAV Approach chart containing the different minima lines is provided in the Activity 15 concerning procedure publication.
4.3.5.A common misunderstanding arises from the fact that the term RNAV is used to refer to a navigation capability as well as to operations and chart naming. Approaches with or without vertical guidance down to LNAV, LNAV/VNAV or LPV minima are a sub-category of RNAV approaches and as such published on charts with a title in the formRNAV (GNSS) RWY XX.The Navigation specification for these approaches is RNP APCH, as described in the ICAO PBN Manual [1] and navigation performance is expressed as an RNP value. According to PANS ATM [8] section 12.3, the term RNAV is currently used in approach clearance phraseology.In this guidance PBN Manual terminology will be used wherever possible, referring to the above procedures as RNP APCH and specifying the minima line to be used for a specific operation.
4.3.6.Note: Despite the use of different terminology, the RNP APCH procedures defined in the PBN Manual have already been implemented in a number of States. Although not all standardisation documents are using the same terminology, sufficient elements can be found in the standards to support RNP APCH implementation. This guidance provides a list of applicable standards and documents and the glossary and the table above can be used as a cross reference to understand the terminology.
4.4.Provision of vertical guidance
4.4.1.An important distinction between different types of RNP APCH operations is the provision of vertical guidance. RNP APCH to LNAV and LP minima include only lateral guidance and are flown to an MDA while RNP APCH procedures with vertical guidance (APV) are flown to DA, which may be lower than the MDA thus potentially increasing airport accessibility. In addition, the provision of vertical guidance improves pilot situational awareness, thus improving safety.
4.4.2.The procedure design criteria and the construction of a vertical profile are different for the different flavours of RNP and should be given particular consideration. For RNP APCH to LNAV and LP minima, only lateral guidance is provided.
4.4.3.For RNP APCH to LNAV/VNAV minima, vertical guidance is provided in addition to the lateral guidance same as for LNAV-only. The theoretical vertical descent profile is defined by a geometrical path with fixed flight path angle. The vertical path is usually defined between 50ft above the runway threshold and a final capture point (for example the FAF). Vertical deviations are usually linear. Given that the vertical path is based on barometric inputs, it is very important that the correct local pressure setting (QNH) is entered into the system and temperature limitsare published on the chart.
4.4.4.RNP APCH to LPV minima is based on GNSS and SBAS. The vertical guidance is angular and the final approach segment profile is defined in the Final Approach Segment Data Block (FAS DB). Integrity of the FAS DB data is maintained through the use of a CRC.
PBNTF5 WP05 Rev 1 Guidance Material RNP APCH Updated August 2011.doc
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Revision 1
5.PART B – GUIDANCE ON THE IMPLEMENTATION OF RNP APCH
5.1.General