EUROPEAN ORGANISATION FOR THE SAFETY OF AIR NAVIGATION EUROCONTROL EUROCONTROL EXPERIMENTAL CENTRE

Transcription

1 EUROPEAN ORGANISATION FOR THE SAFETY OF AIR NAVIGATION EUROCONTROL EUROCONTROL EXPERIMENTAL CENTRE FLIGHT DECK USER REQUIREMENTS FOR AIRBORNE SPACING (SEQUENCING AND MERGING) Volume I Project EVP/WP3 Version: 2.3 Issued: July 2006 The information contained in this document is the property of the EUROCONTROL Agency and no part should be reproduced in any form without the Agency s permission. The views expressed herein do not necessarily reflect the official views or policy of the Agency.

2 DOCUMENTATION PAGE Reference: Flight deck URD Volume I Originator: EEC - SSP (Sector Safety and Productivity) Sponsor: EUROCONTROL Security Classification: Unclassified Originator (Corporate Author) Name/Location: EUROCONTROL Experimental Centre Centre de Bois des Bordes B.P.15 F Brétigny-sur-Orge CEDEX FRANCE Telephone: +33 (0) Sponsor (Contract Authority) Name/Location: EUROCONTROL Agency 96, Rue de la Fusée B Brussels BELGIUM Telephone: TITLE: FLIGHT DECK USER REQUIREMENTS FOR AIRBORNE SPACING (SEQUENCING AND MERGING) Authors Eric Hoffman, Nayen Pène (Steria), Karim Zeghal Date 07/2006 Pages xi + 51 Figures 6 Tables 2 Annexes 1 (separate document) References 18 Contacts: Eric Hoffman, SSP scientific & technical manager +33 (0) eric.hoffman@eurocontrol.int Karim Zeghal, project leader +33 (0) karim.zeghal@eurocontrol.int Descriptors (keywords): ADS-B, airborne spacing, ASAS, flight deck systems, user requirements, real-time experiment, sequencing applications. Abstract: This document describes the set of user requirements to implement an Airborne Separation Assurance System (ASAS) interface for sequencing and merging applications within a flight deck.

3 Release Date of the release Description of the release /06/05 - Complete update of MCS ASAS Spacing URD version Make the document applicable to any flight deck and/or pseudo-pilot position. - Explicit general performance requirements. - Integrate and define new application follow route then merge Modifications (sections affected & relevant information) All /07/05 - Minor editorial updates All /12/05 - Wake turbulence information 4.1.1, 5.1.1, /01/06 - Improved suggested speed calculation: requirement revisited so as to be consistent with latest MCS implementation /05/06 Minor editorial updates, plus: - Default speed mode configuration - ASAS link not displayed after feasibility check phase - Bearing information, as displayed during the identification phase, shall be magnetic bearing instead of relative bearing. - Correction of incomplete statement regarding speed guidance when spacing task is ended (actually depends on the ASAS speed mode) /07/06 - Clarification: display of advisories during the check feasibility phase - Clarification: units in turn correction formula - Update of general description , 3.1, 5.1.1, 5.4.1, 7.1,

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5 TABLE OF CONTENTS LIST OF ANNEXES...VII LIST OF FIGURES...VII LIST OF TABLES...VII REFERENCES...VIII EEC REPORTS...IX ABBREVIATIONS AND ACRONYMS...X 1. INTRODUCTION SCOPE OF THE DOCUMENT OVERVIEW OF THE DOCUMENT TERMINOLOGY GENERAL DESCRIPTION BACKGROUND SPACING INSTRUCTIONS OPERATIONAL REQUIREMENTS TARGET IDENTIFICATION SPACING INSTRUCTIONS Phases of the spacing instruction Remain behind Heading then Remain behind Merge behind Heading then Merge behind Follow route then Merge behind: TERMINATION OF SPACING Termination determined by the controller Termination requested by the instructed aircraft Procedural termination PERFORMANCE REQUIREMENTS General parameters Specific sequencing and merging parameters Airborne parameters SYSTEM REQUIREMENTS TARGET AIRCRAFT Necessary information Equipments for the target aircraft GROUND INSTRUCTED AIRCRAFT Necessary information Equipment for the instructed aircraft COCKPIT SIMULATOR IN A SIMULATED ENVIRONMENT Flight deck URD Version /07/06 v

6 5. COCKPIT FUNCTIONAL REQUIREMENTS TARGET IDENTIFICATION Requirements Advisories and alerts SPACING INSTRUCTION General requirements Spacing information Speed guidance Lateral guidance Engagement and disengagement of the applications Advisories and alerts TERMINATION OF SPACING PSEUDO-PILOT POSITIONS Target identification Spacing instruction Termination of spacing Advisories and alerts COCKPIT HMI REQUIREMENTS GENERAL HMI REQUIREMENTS Input device Display of Target Information Spacing Indicator Guidance Indicator Advisories and alerts INTEGRATED SYSTEM IN THE COCKPIT STAND-ALONE SYSTEM IN THE COCKPIT PSEUDO-PILOT POSITIONS PROPOSED ALGORITHMS POSITIONING OF THE TARGET AIRCRAFT Target position Direct distance Magnetic bearing CALCULATION OF THE SPACING VALUE Distance-based spacing for Remain behind Time-based spacing for Remain behind Spacing value for Remain behind on a selected track (HDG mode) Distance-based spacing for Merge behind Time based spacing for Merge behind Spacing value for Heading then Merge behind CALCULATION OF SPACING TREND AND POSITIONING OF PREDICTIVE SPACING Closure rate value Spacing trend value Time estimate before reaching the desired spacing value Predictive spacing symbol SUGGESTED SPEED CALCULATION Variables Basic calculation Filtering of the suggested speed Improved suggested speed calculation vi Flight deck URD Version /07/06

7 LIST OF ANNEXES See volume II of this report. LIST OF FIGURES Figure 1. Spacing (sequencing and merging) instructions... 3 Figure 2. Magnetic bearing to target aircraft Figure 3. Basic filtering of the suggested speed Figure 4. Algorithm principle of the improved suggested speed Figure 5. Estimation of the change in target IAS, ending with steady evolution Figure 6. Estimation of the change in target IAS, ending at history horizon limit LIST OF TABLES Table 1. Spacing instructions for sequencing arrival flows Flight deck URD Version /07/06 vii

8 REFERENCES [1] E. Hoffmann, N. Pène, K. Zeghal, ASAS Spacing User Requirement Document, EEC document version 2.0, 28/04/2005. [2] I. Grimaud, E. Hoffman, L. Rognin, K. Zeghal, EACAC 2000 Real-Time experiments : Pilots perspectives, EEC Report version 3.0, 16/01/2002 [3] C. Shaw, K. Zeghal, CDTI Evaluation System : User Requirement Document, EEC document version 1.4, 19/10/1998 [4] CARE/ASAS/EUROCONTROL, Activity 5 Description of a first package of GS/AS applications, CA version 2.2, 30/09/2002 [5] EUROCONTROL/FAA, Principles of Operations for the Use of Airborne Separation Assurance Systems, EUROCONTROL/FAA Cooperative R&D Edition 7.1, 2001 [6] E. Hoffman, D. Ivanescu, C. Shaw, K. Zeghal, analysis of constant time delay airborne spacing between aircraft of mixed types in varying wind conditions, USA/Europe Air Traffic Management R&D Seminar, Budapest, Hungary, 2003 [7] J.R. Kelly and T.S Abbott., In-trail spacing dynamics of multiple CDTI equipped aircraft queues, NASA TM-85699, 1984 [8] J.A. Sorenssen and T. Goka, Analysis of in-trail following dynamics of CDTI-equipped aircraft, Journal of Guidance, Control and Dynamics, 6, 1983, pp [9] A. Pritchett and L. Yankosky, Simultaneous Design of Cockpit Display of Traffic Information & Air Traffic Management Procedures, SAE Transactions Journal of Aerospace, 1998 [10] A. Pritchett and L. Yankosky, Pilot performance at new ATM operations: maintaining intrail separation and arrival sequencing, AIAA Guidance, Navigation and Control, Denver, Colorado, USA, 2000 [11] D.H. Williams, Self-separation in terminal areas using CDTI, Human Factors Society Annual Meeting, 1983 [12] R.M. Oseguera-Lohr, G.W. Lohr, T.S. Abbott and T.M. Eischeid, Evaluation of operational procedures for using a time-based airborne interarrival spacing tool, Digital Avionics Systems Conference, Irvine, California, USA, [13] J. Hammer, Preliminary analysis of an approach spacing application, FAA/Eurocontrol R&D committee, Action plan 1, ASAS Technical Interchange Meeting, 2000 [14] P.U Lee, J.S. Mercer, L. Martin, T. Prevot, S. Shelden, S. Verma, N. Smith, V. Battiste, W. Johnson, R. Mogford and E. Palmer, "Free maneuvering, trajectory negotiation, and self-spacing concept in distributed air-ground traffic management", USA/Europe Air Traffic Management R&D Seminar, Budapest, Hungary, 2003 [15] I. Grimaud, E. Hoffman, L. Rognin, K. Zeghal, "Delegating upstream - Mapping where it happens ", USA/Europe Air Traffic Management R&D Seminar, Santa Fe, New Mexico, USA, 2001 viii Flight deck URD Version /07/06

9 [16] I. Grimaud, E. Hoffman, L. Rognin, K. Zeghal, "Spacing instructions in approach: assessing usability from the air traffic controller perspective", AIAA Guidance, Navigation, and Control, Austin, Texas, USA, 2003 [17] I. Grimaud, E. Hoffman, L. Rognin, K. Zeghal, "Towards the use of spacing instructions for sequencing arrival flows", ICAO Operational datalink Panel (OPLINK-P), WGA, WP/12, Annapolis, Maryland, USA, 2003 [18] EUROCONTROL/FAA/EUROCAE/RTCA Requirements Focus Group (RFG), Package I, Operational Performance Assessment, Enhanced sequencing and merging operations, Version 1, January [19] EUROCONTROL/FAA/EUROCAE/RTCA Requirements Focus Group Application Definition Sub Group (RFG-AD-SG), Package 1 Operational Service and Environment Description, Version 1, February EEC REPORTS CoSpace (2004a). CoSpace 2003 Flight deck experiment. Assessing the impact of spacing instructions from cruise to final approach. EEC Report No CoSpace (2004b). CoSpace 2002 Flight deck experiments. Assessing the impact of spacing instructions from cruise to initial approach. EEC Report No Flight deck URD Version /07/06 ix

10 ABBREVIATIONS AND ACRONYMS Abbreviation ACAS ACDU ADS-B AGI ASAS ASI ATC ATCO ATD ATIS ATM AudioLAN CDTI CLR CPA CR DIR TO DIS EACAC EATM ECAM EEC EFIS CP EONS ESCAPE E-TMA EUROCONTROL EVP FCU FMGS ft FL FMA FMS GS HDG HMI De-Code Airborne Collision Avoidance System ASAS Control and Display Unit Automatic Dependant Surveillance Broadcast ASAS Guidance Indicator Airborne Separation Assistance System ASAS Spacing Indicator Air Traffic Control Air Traffic Controller Along Track Distance Automatic Terminal Information Service Air Traffic Management Audio Local Area Network Cockpit Display of Traffic Information Clear Closest Point of Approach Closure Rate Direct To Distributed Interactive Simulation Evolutionary Air-ground Co-operative ATM Concept European Air Traffic Management SBU Electronic Centralised Aircraft Monitor EUROCONTROL Experimental Centre Electronic Flight Instrument System Control Panel EUROCONTROL Open and generic ATC graphics System EUROCONTROL Simulation Capability and Platform for Experimentation Extended Terminal Manoeuvring Area European organisation for the safety of air navigation EATM Validation Project Flight Control Unit Flight Management and Guidance System feet Flight Level Flight Mode Annunciator Flight Management System Ground Speed Heading Human-Machine Interface x Flight deck URD Version /07/06

11 Abbreviation IAS ICAO IEEE kt LNAV LSK MASS MCDU MCS NAR ND NI NM OGS PA PF PFD PNF RA SSR TA TAS TCAS TGS TIS-B TMA VLS WPT De-Code Indicated Air Speed International Civil Aviation Organization Institute of Electrical and Electronic Engineers knot Longitudinal Navigation Line Select Key Multi Aircraft Simplified Simulator Multipurpose Control Display Unit Multi-aircraft Cockpit Simulator Non Altitude Reporting Navigation Display Non Intruding Nautical Mile Own Ground Speed Proximate traffic Pilot Flying Primary Flight Display Pilot Not Flying Resolution Advisory Secondary Surveillance Radar Traffic Advisory True Air Speed Traffic Collision Alert System Target Ground Speed Traffic Information Service Broadcast Terminal Manoeuvring Area Lowest Selectable speed Waypoint Flight deck URD Version /07/06 xi

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13 1. INTRODUCTION 1.1. SCOPE OF THE DOCUMENT This document describes the set of user requirements to implement an Airborne Separation Assurance System (ASAS) interface for sequencing and merging applications [1][2][3] within a flight deck. The user requirements for this system should cover: The case of an integrated system within the existing interface of a cockpit simulator and/or flight deck, for example using the Multipurpose Control and Display Unit (MCDU) for data entry and the Navigation Display (ND) and/or Primary Flight Display (PFD) for display. The case of a stand-alone system which could be used for retrofit on a flight deck and/or cockpit simulator. The case of pseudo-pilot positions used to simulate traffic during ground real-time experiments OVERVIEW OF THE DOCUMENT The document is organised as follows: Section 2 presents a general description of the sequencing and merging applications. Section 3 presents the system requirements for the platform. Section 4 presents the functional requirements of the ASAS for sequencing and merging. Section 5 presents the Human Machine Interface (HMI) requirements of the ASAS for sequencing and merging. Section 6 presents the proposed algorithms to comply with the requirements of the spacing applications TERMINOLOGY In order to ensure clarity and readability, the following notations are applied to this document: shall is used whenever a mandatory requirement is expressed. should is used to express a recommendation. may is used to express an option. will is used to express a future expectation. Flight deck URD Version /07/06 1

14 2. GENERAL DESCRIPTION 2.1. BACKGROUND Airborne spacing involves a new allocation of tasks between controller and flight crew envisaged as one possible option to enhance the management of arrival flows of aircraft. It relies on the ability of the controller to task the flight crew to maintain a given spacing with respect to the preceding aircraft. The motivation is neither to transfer problems nor to give more freedom to the flight crew, but to identify a more effective task distribution beneficial to all parties without modifying responsibility for separation provision [5]. Airborne spacing assumes air-to-air surveillance (ADS-B) along with cockpit automation (ASAS). No significant change on ground systems is initially required. The work performed so far at the EUROCONTROL Experimental Centre allowed developing and refining a set of spacing instructions for sequencing and merging (S&M) arrival flows of aircraft, forming part of the input to an harmonisation process between US and Europe [19]. To gradually assess their operational feasibility, potential benefits and limits, after an initial air-ground experiment, two streams of independent air and ground experiments are conducted with a unified perspective SPACING INSTRUCTIONS The spacing instructions require aircraft to achieve or maintain a particular spacing on common or converging trajectories (Figure 1). For example, with a heading then merge, the task of the flight crew is defined as follows: (1) in order to achieve the desired spacing, the flight crew flies an initial heading issued by the controller, and initiates the resume action when the desired spacing is achieved; (2) in order to maintain the desired spacing, the flight crew adjusts the aircraft speed. It should be noticed that the aircraft is not following the target it is on his own navigation. The use of spacing instructions is composed of three phases: (1) target identification, in which the controller designates the target aircraft to the flight crew, (2) issuing of the spacing instruction, and (3) termination of the spacing instruction. An example dialogue between controller and pilot is as follows: 1. Controller designates the target aircraft using e.g. transponder code ( XYZ, select target 4522 ) 2. Flight crew identifies target aircraft ( XYZ, target 4522 identified, 8 o clock, 30 miles ) 3. Controller confirms the identification ( XYZ, target 4522 correct ) 4. Controller, when appropriate, issues the spacing instruction ( XYZ, continue present heading then merge WPT 90 seconds behind target ) 5. Flight crew continues on heading, then initiates direct when spacing achieved ( XYZ, merging WPT ), then adjusts speed to maintain 90 seconds 6. Controller, when appropriate, cancels spacing ( XYZ, cancel spacing, speed 180 knots ) 2 Flight deck URD Version /07/06

15 Remain Merge Vector then merge To maintain spacing To maintain spacing at waypoint To achieve then maintain spacing at waypoint Figure 1. Spacing (sequencing and merging) instructions. 3. OPERATIONAL REQUIREMENTS The use of spacing instructions is composed of three phases: 1. Target identification, in which the controller designates the target aircraft to the flight crew of the spacing instructed aircraft. 2. Spacing instruction, in which the controller specifies the task to be performed by the flight crew. 3. Termination of the spacing instruction TARGET IDENTIFICATION The flight crew shall be able to select an aircraft as target using the unique identifier provided by the controller (e.g. SSR code) in the instruction. This identifier will be referenced as the target aircraft ID and it shall be present in the ADS-B identification data messages. If no ADS-B or TIS-B information corresponding to the target aircraft ID is received, the flight crew shall advise ATC. The flight crew shall be able to positively identify the target aircraft with the on-board traffic display. The flight crew shall make a positioning report to ATC which shall include relative distance and magnetic bearing 1 and may include other information such as relative altitude. The target selection will be complete once the positioning has been confirmed by ATC SPACING INSTRUCTIONS Depending on the situation, the controller may issue one of the following spacing instructions (Table 2) for sequencing and merging arrival traffic in the en-route airspace or Terminal Control 1 The magnetic bearing to the target aircraft is the angle between the direction of magnetic North and the direction of the target aircraft (See below). Flight deck URD Version /07/06 3

16 Area (TMA). These instructions require aircraft to achieve or maintain a particular spacing on common or converging trajectories. To maintain spacing To achieve then maintain spacing Common trajectories Converging trajectories Remain behind (see 3.2.2) Merge behind (see 3.2.4) Heading then remain behind (see 3.2.3) (not considered yet) Heading then merge behind (see 3.2.5) or Follow route then merge behind (see 3.2.6) Table 1. Spacing instructions for sequencing arrival flows. The spacing value is determined either in distance or time. Distance-based spacing may better fit in with current practices, particularly in en-route; but time-based spacing might be more appropriate in TMA for arrivals (descending traffic). In addition, the desired spacing value in the spacing procedure shall be maintained either exactly or at least. An exact spacing value shall be maintained by the flight crew within a tolerance (e.g. 90 seconds). With an at least spacing value, the flight crew shall ensure that the spacing value does not increase and remains above specified minimum value (within tolerances). A spacing instruction is by default valid until further advised and may also be valid until a designated waypoint (not covered in this document). The controller shall ensure that the applicability conditions are satisfied before issuing and during a spacing instruction. Some are specific to each application and the following apply to all the applications listed below: Positions of aircraft (altitude and relative position) shall be compatible with the instruction. Performances of aircraft shall be compatible, particularly speed and rate of descent. Aircraft shall have appropriate ASAS capability. In all cases, the controller shall still handle vertical profiles. In descent, the flight crew may adjust the aircraft s rate of descent when needed (as in current operations). As for any instruction, a new spacing instruction with the same target aircraft can override a previous one Phases of the spacing instruction The spacing instruction is composed of three main phases: Check feasibility phase: The check feasibility phase is meant for the crew to assess feasibility of the spacing instruction and acknowledge its implication before activating it. It starts once all 4 Flight deck URD Version /07/06

17 parameters for the spacing instruction have been entered and ends when the spacing instruction is activated. Acquisition phase: The acquisition phase is meant for the crew to acquire the desired spacing value for cases when the initial spacing value is slightly greater or lower than the desired spacing value (thus possibly outside the tolerances). During the acquisition phase, the current spacing value shall monotonously evolve towards the desired spacing value (i.e. the spacing error shall not increase). The acquisition phase starts when the spacing instruction is activated. It ends when the time limit is attained (e.g. merge point), or when the spacing value falls within the tolerance margin of the desired spacing value. Maintain phase: The maintain phase is meant for the crew to maintain spacing within the set tolerances of the desired spacing. It starts when the spacing instruction is activated for cases when the initial spacing value is within the set tolerances or when the acquisition phase ends Remain behind Description: The instructed aircraft remains behind the target aircraft at a spacing value determined by the controller. If the desired spacing is not obtained at the start of the instruction, it shall be acquired by the instructed aircraft in a limited time (to be specified). Specific applicability conditions: The controller shall ensure that the two concerned aircraft have been instructed to fly along the same horizontal route from the initiation of the manoeuvre until the termination. The current spacing value shall be compatible with the spacing value given to the instructed aircraft. Task repartition: The controller: shall indicate the desired spacing value. The flight crew: shall adjust speed to acquire, if necessary, and maintain the desired spacing value; Flight crew controlled parameters: Speed Spacing value determination: The spacing value shall be the distance or time along track to the target aircraft s current position. For time-based spacing, the spacing value represents a constant time delay behind the target aircraft (i.e. the time elapsed since the moment at which the target aircraft passed the instructed aircraft present along track position. Flight deck URD Version /07/06 5

18 Heading then Remain behind Description: The instructed aircraft is given a heading by the controller, and shall resume own navigation when the desired spacing is obtained. The instructed aircraft shall then rejoin the planned trajectory at a standardised fixed angle, whilst maintaining the spacing behind the target aircraft. Once the instructed aircraft has rejoined the original trajectory, the spacing instruction will become a remain behind application. Specific applicability conditions: The two concerned aircraft shall be flying along the same horizontal route from the initiation of the manoeuvre until the termination. Initial spacing is lower and desired spacing cannot be achieved by speed variation alone; therefore, the controller shall give a heading instruction. Task repartition: The controller: shall give a heading instruction in order to provide the desired spacing value at the point where the instructed aircraft rejoins the original route; shall indicate the desired spacing value. The flight crew: shall fly the controller instructed heading; shall rejoin original route at a standardised fixed angle (e.g. 45 ) when the predicted spacing value equals the desired spacing value, and shall report resuming action and adjust speed to maintain the desired spacing value behind the target aircraft, then; after rejoining original route, shall remain behind target aircraft. Flight crew controlled parameters: Resume action at the appropriate time (i.e. when the desired spacing value is reached). Speed, after the resume turn to rejoin original route Spacing value determination: The spacing value shall be the predicted distance or time between the target and instructed aircraft, at the time at which the target aircraft passes the point where the instructed aircraft will rejoin its original track (i.e. this shall include an estimation of own/instructed aircraft track including two turns at the resume and rejoin points), assuming an immediate resume turn Merge behind Description: 6 Flight deck URD Version /07/06

19 The two aircraft are flying along merging trajectories. The instructed aircraft adjusts its speed to be at the desired spacing behind the target aircraft at the merge point. After the merge point, the spacing instruction will become a remain behind application. Specific applicability conditions: The target aircraft and the instructed aircraft are routed direct to the merge point. The two concerned aircraft shall have common trajectories after the merge point as the spacing instruction will continue past the merge point (as a remain behind ). The predicted spacing at the merge point shall be equal to the desired spacing value. Task repartition: The controller: shall indicate the merge point, and the desired spacing value to be applied. The flight crew: shall adjust speed to acquire, if necessary, and maintain the desired spacing value at the merge point; Flight crew controlled parameters: Speed Spacing value determination: The spacing value shall be the predicted distance or time between the target and instructed aircraft, at the time at which the target aircraft passes the designated merge point (i.e. this shall include an estimation of own/instructed and target aircraft along track distance, including their respective turns at the merge point) Heading then Merge behind Description: The instructed aircraft is given a heading by the controller, and shall merge towards the designated waypoint behind the target aircraft when the predicted spacing at the merge point equals the desired spacing. Once the instructed aircraft has resumed navigation towards the merge point, the spacing instruction will become a merge behind application. Specific applicability conditions: The target aircraft is routed direct to the merge point. The target and instructed aircraft are flying along routes converging to the merge point and have common trajectories after the merge point. Initial spacing is lower and desired spacing cannot be achieved by speed variation alone; therefore, the controller shall give a heading instruction. Task repartition: Flight deck URD Version /07/06 7

20 The controller: shall give a heading instruction in order to provide the desired spacing value between the target and the instructed aircraft and; shall indicate the merge point, and the desired spacing value to be applied. The flight crew: shall fly the controller instructed heading; shall resume own navigation to the merge point when the predicted spacing value at the merge point equals the desired spacing value, and at the same time; shall report resuming action, and then; shall merge behind the target aircraft. Flight crew controlled parameters: Resume action is performed by the flight crew at the appropriate time. NOTE: Speed will be controlled by the flight crew only after the resume turn towards the merge point, that is, when the spacing instruction becomes a merge behind application. Spacing value determination: The spacing value shall be the predicted distance or time between the target and instructed aircraft, at the time at which the target aircraft passes the designated merge point (i.e. this shall include an estimation of along track distances, including turns at the resume and merge points), assuming an immediate resume turn Follow route then Merge behind: Description: The instructed aircraft flies the planned trajectory and shall merge towards the designated waypoint behind the target aircraft when the predicted spacing at the merge point equals the desired spacing. Once the instructed aircraft has resumed navigation towards the merge point, the spacing instruction will become a merge behind application. Specific applicability conditions: The target aircraft is routed direct to the merge point. The instructed aircraft is flying a route passing by the merge point and both aircraft have common trajectories after the merge point. Initial spacing is lower and desired spacing cannot be achieved by speed variation alone; therefore, the controller shall give a heading instruction. Task repartition: The controller: 8 Flight deck URD Version /07/06

21 shall indicate the merge point, and the desired spacing value to be applied. The flight crew: shall resume own navigation to the merge point when the predicted spacing value at the merge point equals the desired spacing value, and at the same time; shall report resuming action, then; shall merge behind the target aircraft. Flight crew controlled parameters: Resume action is performed by the flight crew at the appropriate time. NOTE: Speed will be controlled by the flight crew only after the resume turn towards the merge point, that is, when the spacing instruction becomes a merge behind application. Spacing value determination: The spacing value shall be the predicted distance or time between the target and instructed aircraft, at the time at which the target aircraft passes the designated merge point, assuming an immediate resume turn TERMINATION OF SPACING It is the responsibility of the controller to cancel the spacing instruction and it is generally subject to an explicit communication between the controller and the instructed aircraft. If The termination of the spacing instruction is either: initiated by the controller (in most cases), requested or initiated by the instructed aircraft, or procedural Termination determined by the controller The spacing instruction may be cancelled at any time by the controller when he/she estimates it is no longer appropriate. If the controller considers that the spacing instruction is not being implemented correctly (e.g. unexpected events) or that the separation may be lost, he shall cancel the spacing instruction and issue new instructions or clearances as necessary. If required, the controller shall state, at the start of the spacing instruction, a spacing limit after which spacing should be terminated by the instructed aircraft. When a merge behind or remain behind application is ended, the controller shall provide the instructed aircraft with a speed indication in the new instruction. When a spacing instruction is cancelled, the new instruction issued by the controller may include a new or altered spacing instruction with the same target aircraft (e.g. new desired spacing value). Flight deck URD Version /07/06 9

22 Termination requested by the instructed aircraft The flight crew from the instructed aircraft shall report to the controller that the spacing instruction cannot be complied with any more if: no information or corrupt information is received from the target aircraft for more than a given time (to be defined), the applicability conditions are not met any more (e.g. the target aircraft has increased speed and the instructed aircraft cannot acquire or maintain spacing any more), It has become unsafe to continue the spacing instruction (e.g. serious technical failure). In answer to that report, the controller will decide whether to cancel or modify the spacing instruction and shall in any case issue a new (or modified) instruction. NOTE: The relationship between the spacing instruction and ACAS, in particular where a Resolution Advisory is given, will need to be clarified Procedural termination A procedural limit may be defined (e.g. in the AIP) after which the sequencing and merging applications shall be terminated (e.g. at a designated waypoint or below a given altitude above airport level) PERFORMANCE REQUIREMENTS To perform spacing instructions, performance requirements need to be set as defined in the RFG document [1]. They may be classified as follow: General parameters, Spacing parameters, Airborne parameters General parameters Some general ATC requirements may have an impact on the performance requirements for spacing: Minimum ATC separation is a static parameter for one physical location and should not be infringed. Its respect is under the responsibility of the controller. If the minimum ATC separation has no impact on the spacing instruction itself, it may generate constraints in terms of performance requirements Specific sequencing and merging parameters The main objective of the sequencing and merging applications is to acquire and maintain a desired spacing value behind a designated target aircraft. The following parameters are defined: 10 Flight deck URD Version /07/06

23 Desired spacing is a static parameter during one instruction. It is determined by ATC and may depend on various factors such as the environment (e.g. TMA or E-TMA) or aircraft performance. Spacing tolerance is a static parameter for one physical location; it may depend on the type of airspace. The spacing tolerance can be the same below or above the desired spacing (e.g. +/-0.5 NM or +/-5s) or can be differentiated: Spacing tolerance below the desired spacing value is constrained by safety considerations; the condition being that Desired Spacing Spacing Tolerance > Minimum ATC separation + Buffer. Spacing tolerance above the desired spacing value can be constrained by efficiency and/or safety considerations. It does not apply for instructions requiring to maintain an at least spacing value. The following performance requirements can be set concerning the spacing instructions: Spacing accuracy is the main parameter and may include the following: Respect of spacing tolerance during maintain phase (e.g. 99%) Respect of spacing tolerance at the merge point for merge applications Respect of spacing tolerance at the end of the resume turn for heading then merge and follow route then merge applications Maximum deviation of the mean spacing error during the maintain phase (e.g. 2.5s) Desired spacing value: Minimum value (e.g. 3NM or 90s) Maximum value Closure rate (indicator of stability), including: Maximum value during acquisition phase (e.g. 30kt with standard deviation of 5kt) Maximum value during maintain phase (e.g. 10kt) Shall not change sign during acquisition under calm wind conditions Rate of violation of the minimum ATC separation Success rate of the applications. The results can be influenced by factors such as airborne availability, continuity and controller/flight crew procedural communications Airborne parameters Target state data Target state data shall be available from the start, even before the target selection, so that the target selection can be performed immediately. The availability, continuity and accuracy of that data influence directly the performance of the sequencing and merging applications. Performance requirements should be defined for the following values: Accuracy of target horizontal position Flight deck URD Version /07/06 11

24 Accuracy of the target vertical position Containment bound of the target aircraft Accuracy of target ground speed Update rate interval of the ADS-B report Precision of reference time Report time error Own aircraft data Data from own aircraft shall also be available to perform the necessary calculations and comply with the sequencing and merging applications. Performance requirements should be defined for the following values: Accuracy of own aircraft horizontal position Accuracy of the own aircraft vertical position Containment bound of own aircraft Accuracy of own aircraft ground speed Accuracy of own aircraft track and heading Integrity of flight plan data Precision of reference time General airborne parameters General performance requirements should also be defined for the following values: Airborne availability which depends on: Availability of target aircraft s sensors, systems, ADS-B out and identification function Availability of own aircraft s ADS-B in, sensors, systems and processing function Airborne continuity which depends on: Continuity of target aircraft s ADS-B out, sensors, systems and identification function Continuity of own aircraft s ADS-B in, sensors, systems and processing function Acquisition range air-air Maximum latency Processing In addition to the requirements on availability and continuity of the processing function (included in airborne general parameters), performance requirements should also be defined for: 12 Flight deck URD Version /07/06

25 Accuracy of spacing value calculation Accuracy of suggested speed calculation Stability of suggested speed calculation Fault detection time Maximum state data age before target is considered to be lost 4. SYSTEM REQUIREMENTS In order to conduct sequencing and merging operations in the general CNS/ATM environment, system requirements shall be met by each of the following participants: Target aircraft Ground ATC Instructed aircraft 4.1. TARGET AIRCRAFT Necessary information The hypothesis is made in this document that the following data shall be available from the surrounding traffic: Identification data which shall comprise at least: time stamp aircraft ID (e.g. SSR code) aircraft callsign State data which should comprise at least: time stamp 3D position: aircraft coordinates and altitude 3D velocity: aircraft track, ground speed and vertical speed wake turbulence category At this stage, no intent data from surrounding traffic is required Equipments for the target aircraft In order to be eligible to become a target aircraft, surrounding traffic shall be equipped with: Aircraft sensors (e.g. GNSS) Flight deck URD Version /07/06 13

26 Aircraft systems (e.g. FMS) Surveillance processing function ADS-B out function SSR interrogation reply However, if an aircraft is not equipped with these systems, the ADS-B messages concerning this aircraft could be replaced by TIS-B messages transmitted from the ground by ATC GROUND In all cases, the ATC on ground shall be equipped with surveillance functions (e.g. radar). In case an aircraft is not equipped as defined above, the ATC on ground should be able to provide TIS-B information for this aircraft; which requires the following additional equipments: ADS-B receive function TIS-B processing function (based on information from ground surveillance means) TIS-B transmit function 4.3. INSTRUCTED AIRCRAFT Necessary information To perform the spacing instructions, inputs are also needed from the instructed aircraft: 3D position: aircraft coordinates and altitude 3D velocity: aircraft track, ground speed and vertical speed flight plan waypoints and coordinates current IAS and selected IAS flight envelope (minimum and maximum speeds) the speed guidance and lateral guidance mode selected The entry of the necessary spacing parameters will be performed by the flight crew Equipment for the instructed aircraft The instructed aircraft shall be equipped with: Aircraft sensors Aircraft systems 14 Flight deck URD Version /07/06

27 Surveillance processing function using data from the aircraft sensors and systems to generate the data required in input from own aircraft ADS-B in function compatible with ADS-B and/or TIS-B information which should gather the data required in input from the target aircraft. ASAS processing unit which shall respect the Functional requirements (see 5) described in the document for sequencing and merging applications. A display of target information and an input device which shall respect the HMI requirements (see 6) described in the document for sequencing and merging applications COCKPIT SIMULATOR IN A SIMULATED ENVIRONMENT In the case of a cockpit simulator used in a simulated environment, target aircraft information will be provided in DIS format and the simulator shall be equipped with an ASAS meeting the following requirements: The ASAS for sequencing and merging applications shall respect the Functional requirements (see 5) and the HMI requirements (see 6) described in the document. The system shall be compatible with the Distributed Interactive Simulation (DIS) format described in annexe. It shall be capable of receiving and exploiting the data and it should be capable of broadcasting information in DIS format. Overall performance of the ASAS interface shall not modify (slow down) in a perceptible manner the management of the flight parameters and of the standard cockpit interface on the simulator. Computations for ASAS shall not be perturbed by the reception of a new state vector message from the target aircraft during a computational cycle. The system shall enable the recording of defined flight and ASAS parameters. It shall be possible to modify the defined user parameters for ASAS in a flexible way. An initialisation file (*.ini) may be used. The cockpit simulator shall provide a radio communication facility to and from the crew. The possibility should exist to replay and mute when necessary recorded audio files. 5. COCKPIT FUNCTIONAL REQUIREMENTS 5.1. TARGET IDENTIFICATION Requirements The pilot(s) shall be aware of the status of the systems required for the spacing instruction (see 4.3). Flight deck URD Version /07/06 15

28 The pilot(s) shall have access to an input device (see 6.1.1), enabling to select a target aircraft using its designated identifier (e.g. SSR code). Once a target aircraft has been selected by the flight crew, it shall be distinctly identifiable on a Display of Target Information. In general, this function is fulfilled on a Cockpit Display of Traffic Information (CDTI). On the CDTI, the pilot(s): Shall find information on relative distance and magnetic bearing of the target aircraft Should find information on relative altitude of the target aircraft. Should also find the target aircraft ID during the target identification phase. Additional target information such as callsign, wake turbulence category or ground speed may be displayed on the CDTI or the input device. The pilot should be required to validate the target selection (i.e. when controller confirms the target positioning) Advisories and alerts Advisories and alerts shall be implemented in the system and shall meet the following requirements for target identification: An advisory message shall be displayed if any of the systems required for the spacing instruction is not operational. An explicit advisory message should be displayed if the data format of the entry performed on the input device is not correct. An explicit message shall be displayed if no ADS-B or TIS-B information corresponding to the target aircraft ID is received by the system. The flight crew is required to advise ATC in that case SPACING INSTRUCTION General requirements Once a designated target has been identified and confirmed, the pilot(s) shall be able, through an input device, to select the instructed spacing application (e.g. merge behind). The selection may be partly menu driven and partly contextual if necessary (e.g. depending on whether aircraft is in heading or navigation mode). The system shall require and enable the entry of the spacing parameters relevant for the instruction (see 3.2): Desired spacing value, Whether an exact or «at least» spacing value needs to be maintained, Merge point when applicable. 16 Flight deck URD Version /07/06

29 Once valid spacing parameters have been entered, the system shall: Switch to the check feasibility phase. Compute the spacing value as described in spacing value determination subparagraphs of paragraph 3.2. Compute the speed guidance or the predicted resume point depending on the instruction (see 3.2). Check if the spacing task is feasible, that is, whether the applicability conditions defined in paragraph 3.2 are met (e.g. speed guidance value is within the flight envelope of the aircraft). Display on its CDTI the information necessary for the pilot to check feasibility. During the check feasibility phase, it shall be possible to modify the spacing parameters. If feasible, the spacing instruction shall be activated through a positive action of the flight crew. Once the spacing instruction is activated, the system: Shall switch to the acquisition phase, Shall provide ASAS guidance information in speed (see 5.2.3) or for resume action (see 5.2.4) depending on the spacing instruction, Should provide ASAS spacing information (see 5.2.2) so that the pilot(s) may monitor spacing. This information shall include the current and desired spacing values. It should also include the spacing trend and the spacing tolerance. The system shall switch from the acquisition phase to the maintain phase when the spacing value is stabilized within the tolerance margin. The system shall automatically switch from one spacing application to the next when required (see 5.2.5). Advisories and alerts shall be triggered by the system when necessary (see 5.2.6) Spacing information The ASAS spacing information computed and displayed shall meet the following requirements: The spacing information, as defined in the operational requirements (3.2) should be displayed to enable the flight crew to check whether current spacing is within the tolerance margin or not. The displayed value of current spacing shall be stable (i.e. its value shall not jump abruptly from one value to another and back), even when during aircrafts turns. The value of current spacing shall not change when the system switches from one application to another (e.g. from merge to remain). The spacing trend represents the derivative of the spacing value (i.e. the present evolution of the spacing value). Flight deck URD Version /07/06 17

30 Speed guidance For remain behind and merge behind applications, the main flight crew controlled parameter is speed. The speed guidance is computed by the system and shall be displayed on the ASAS Guidance Indicator (see 6.1.4). Two modes are defined for ASAS guidance in speed: ASAS Managed speed mode, in which the speed is automatically managed by the system to comply with the spacing instruction. ASAS Selected speed mode, in which the flight crew needs to manually adjust the aircraft speed (e.g. on FCU) to comply with the spacing instruction, using the displayed ASAS guidance. The ASAS Selected speed mode shall be available in all cases. If the ASAS Managed speed mode is implemented and enabled in the system, the following functional requirements shall apply for these two modes: The system shall have the ability to switch between the ASAS Managed speed mode and the ASAS Selected speed mode, using the Flight Control Unit, so that the flight crew can take control over the speed at any moment. The system shall always engage the same speed mode when the spacing instruction is activated. This default speed mode (i.e. ASAS Selected speed or ASAS Managed speed) should be configurable (e.g. through a parameter in a configuration/initialisation file, as defined in Volume II, 2.2 of this URD). The flight crew shall be able to differentiate at a glance whether the ASAS managed or selected mode is engaged. When the spacing task is ended, the aircraft shall switch to a selected Speed/Mach mode to prevent undesired speed changes 2. In the case when the ASAS Managed speed mode was used, the value of the selected speed shall be the current speed (i.e. when ending the spacing task, so that the aircraft actually maintains its current speed). In the case when the ASAS Selected speed mode was used, the value of selected speed shall be the one that was last selected before the end of the spacing task. Speed guidance for ASAS shall meet the following requirements: The current spacing value shall respect the operational requirements for acquisition and maintain of the defined applications: For the acquisition phase of merge behind applications, the speed guidance shall ensure that the spacing value is acquired (within the tolerance margin) and stabilised (small spacing trend) at the merge point. For the acquisition phase of remain behind applications, the speed guidance shall ensure that the spacing value is acquired and stabilised within the specified time limit. For the maintain phase, the speed guidance shall ensure spacing is maintained and that the performance requirements are met. 2 In addition, when the spacing task is ended by a controller instruction (i.e. not by automatic termination), the selected speed/mach mode should be best adapted to comply with the speed instruction that the controller is expected to issue when ending spacing. 18 Flight deck URD Version /07/06