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Free Flight - Flight Management SystemBrite/EuRam project

3FMSFUNCTIONAL DEFINITION

DOCUMENT

(3FMS - FDD)

P/N: TBD

Rev: 09b

Date: 19th January, 1999

SXT AS SI ETG NLR RTSN2 DERA

Author’s name P. JasselinG. SainthuileC. Solans

V. MahoF. Marchetto

M. Leeson M. Paus J. de SousaD. Tilsner

Approvals

3FMS - FUNCTIONAL DEFINITION DOCUMENT

3FMS PROJECT 1

TABLE OF CONTENTS

1. SCOPE .................................................................................................................................................................................. 2

1.1 PURPOSE............................................................................................................................................................................ 21.2 3FMS DEMONSTRATOR OVERVIEW............................................................................................................................ 21.3 CONTENT........................................................................................................................................................................... 3

2. REFERENCES..................................................................................................................................................................... 3

3. FUNCTIONAL DESCRIPTION ........................................................................................................................................ 4

3.1 INTRODUCTION ............................................................................................................................................................... 43.1.1 FMS BACKGROUND .................................................................................................................................................. 4

3.2 3FMS PROTOTYPE OVERVIEW ..................................................................................................................................... 63.2.1 DESIGN CONSIDERATIONS AND TERMINOLOGY................................................................................................. 63.2.2 3FMS FUNCTIONAL BLOCK DIAGRAM .................................................................................................................. 9

3.3 TWG SEPARATION FUNCTION ................................................................................................................................... 123.3.1 OVERVIEW................................................................................................................................................................ 123.3.2 TRAFFIC SITUATION............................................................................................................................................... 133.3.3 WEATHER SITUATION............................................................................................................................................. 163.3.4 GEOGRAPHIC SITUATION...................................................................................................................................... 203.3.5 DATA MANAGEMENT AND DETECTION............................................................................................................... 233.3.6 CONFLICT RESOLUTION........................................................................................................................................ 25

3.4 MAS OPERATIONS ......................................................................................................................................................... 263.4.1 OBJECTIVES ............................................................................................................................................................. 263.4.2 FUNCTIONAL DESCRIPTION ................................................................................................................................. 26

3.5 TAXI MANAGEMENT .................................................................................................................................................... 283.5.1 OBJECTIVES ............................................................................................................................................................. 283.5.2 FUNCTIONAL DESCRIPTION ................................................................................................................................. 29

3.6 FMS INTERFACE............................................................................................................................................................. 343.6.1 OBJECTIVES ............................................................................................................................................................. 343.6.2 FUNCTIONAL DESCRIPTION ................................................................................................................................. 34

3.7 COMMUNICATION APPLICATIONS............................................................................................................................ 353.7.1 AIR/GROUND APPLICATIONS................................................................................................................................ 353.7.2 AIR/AIR APPLICATIONS .......................................................................................................................................... 38

3.8 HUMAN MACHINE INTERFACE .................................................................................................................................. 413.8.1 INTRODUCTION / ASSUMPTIONS.......................................................................................................................... 413.8.2 FFAS OPERATIONS.................................................................................................................................................. 433.8.3 MAS OPERATIONS ................................................................................................................................................... 48

4. SYSTEM SAFETY ANALYSIS ....................................................................................................................................... 48

5. LIST OF FIGURES ........................................................................................................................................................... 49

6. GLOSSARY OF TERMS.................................................................................................................................................. 50

7. 3FMS TERMINOLOGY................................................................................................................................................... 52


3FMS PROJECT 2

1. SCOPE

1.1 PURPOSEThis document constitutes the report of WP1.2 « 3FMS Function Definition ».It is not intended to provide detailed design specifications for the development of the 3FMS prototype.The latter will be produced in WP2 « Design and Prototyping » (WP 2.2 to 2.6).

This document gives a functional description of the 3FMS Prototype at the system-level.

Figure 1 - Definition of the scope of the FDD

1.2 3FMS DEMONSTRATOR OVERVIEW

The 3FMS demonstrator is the platform that will be used for evaluation of the Free Flight functions developedin the frame of the 3FMS project.

As stated in the project program, the 3FMS Demonstrator will include the following design features• Build on state of the art FMS : the NEW FMS SXT/SI for AIRBUS• AIRBUS driven design: A320 &A340 Families• New on-board free-flight tactical FM functions including communication functions and HMI..;• • Use of high fidelity AIRBUS simulator coupled with realistic ATC and Traffic simulators.• Complement AFMS and AATMS projects,

The 3FMS demonstrator is built around:

• existing functions without modification• existing functions with adaptations• new functions

A/CSIMULATOR

3FMSPROTOTYPE

ATCSIMULATOR

TRAFFICSIMULATOR

3FMSDEMONSTRATOR

FDD SCOPE

HMI


3FMS PROJECT 3

The purpose of the 3FMS demonstrator is to provide an open and flexible Workstation-based prototypingplatform for exploring and validating new Free Flight FMS Functions. As a result, the architecture of the 3FMSprototype should not be considered as representative of an onboard architecture. The implementation as wellas the data flow between the components of the 3FMS demonstrator may not be fully representative of anavionics architecture.

1.3 CONTENT

This document provides:

• background information on existing functions/components,• a general description along with operational considerations for each 3FMS function,• how these 3FMS functions interact together and with the existing functions/components,• what major adaptations to existing functions/components are required.

2. REFERENCES

3FMS Project Program - Brite/EuRam project BE97-4159 , September 11, 1997

3FMS Free Flight Definition Document - 3FMS FFDD, Version 4c - September 9, 1998

RTCA Do-242, Minimum Aviation System Performance Standards for Automatic Dependent SurveillanceBroadcast (ADS-B) - February 1998


3FMS PROJECT 4

3. FUNCTIONAL DESCRIPTION

3.1 INTRODUCTION

The 3FMS prototype provides free-flight tactical Flight Management functions for the detection of Traffic,Weather and Geographic (Terrain and Airspace) obstacles and separation from these obstacles in an economicand comfortable way. A function for taxi phase management is also provided.

In the reminder of this document « TWG Separation » will be used to refer to the combined Traffic, Weatherand Geographic situation and Separation functions.

These 3FMS functions provide new operational capabilities to the A/C and enable to determine the best 4Drouting taking into account new constraints or restrictions related to Traffic, Weather, Terrain and airspace.These new functions combined with the NEW SXT/SI FMS capabilities enable the management of free flighttrajectories and constitute a first step toward free-flight and the transfer of separation responsibilities from theground to the air.

The Free-Flight scenario Definition Document (FFDD) has been used as an input for the operationalrequirements.

3.1.1 FMS BACKGROUND

General description

The Flight Management System is an on-board navigation and performance computing resource that providesthe flight crew with automation for tasks such as flight planning, trajectory prediction and aircraft steering.

Flight management systems have been successfully in use for commercial air transport for over 15 years for twomain reasons.

The first one lies on airspace usage regulations defined by ICAO, Eurocontrol and the FAA with theintroduction of area navigation (RNAV). All FMS provide RNAV capabilities and enable to navigate off theairways defined by VHF beacons (VOR) and allow for direct flight to any position without overfly of groundbased Navigation aids.

The second reason is economical and targeted to airplane operating costs which are time and fuel burn related.One major function of the FMS is the determination of the most economical path taking into account the originairport, the Air Traffic Control route clearances (ATC flight Plan), the destination and the aircraft performanceparameters.

Almost all modern air transport airplanes are equipped with a FMS. A typical installation includes two FlightManagement Computers installed in the electronic bay and two Multi-purpose Control and display units thatallow each of the pilots to enter and review FMS data. For the A320 and A340 airplanes families the Flightguidance function (Autopilot) is hosted by the same computer as the FMS.


3FMS PROJECT 5

Figure 2 - Typical FMS onboard architecture

The New FMS SXT/SI

The 3FMS prototype is built on the NEW FMS SXT/SI for AIRBUS which provides an extensive set ofFlight Management functions from pre-engine start and take-off to landing and engine shut down.

The NEW FMS SXT/SI functions basically include:

• Flight planning: construction of flight plans, assembly and modifications

• Trajectory prediction and performance: predicts the detailed trajectory based upon the airplane andengine performance models and provides performance information

• Navigation: manages the sensors and blends data for best position determination, provides alerts whenposition accuracy or integrity is insufficient

• Lateral and vertical guidance: provides steering to guide the aircraft along the flight plan

• MCDU and EFIS display: constitutes the FMS man-machine interface

• FANS and Data link: RNP, RTA, elaboration and processing of data required for ATC and AOC

In the remainder of this document « New FMS Core» will be used to refer to S/W functions provided bythe NEW FMS SXT/SI.

FMC1 FMC2

InertialReference

System

RadioNavigation

Sensors / GNSSAir DataSystem

Clock & FuelSystem

Air TrafficService

Unit

ElectronicFlight Instrument

System 2MCDU 1 MCDU 2

ElectronicFlight Instrument

System 1

DCDU


3FMS PROJECT 6

3.2 3FMS PROTOTYPE OVERVIEW

3.2.1 DESIGN CONSIDERATIONS AND TERMINOLOGY

The Traffic, Weather and Geographic (TWGdetection functions are in charge of the detection of the objectspotentially conflicting with the ownship. But a centralized approach is required to detect the conflicts and todetermine the most economical deconflicting route.

As a result a single algorithm will be used to solve the TWG conflicts. In the remainder of this document theterms Data Management and Detection (DMD) and Conflict Resolution (CR) will be used to refer to thissingle algorithm.

TWG separation function = Traffic situation + Weather situation + Geographic situation +Data Management and Detection + Conflict Resolution

The Data Management and Detection and Conflict Resolution will manage priorities between the TWGconstraints. It is anticipated that priorities will be dynamic and will change depending on the flight context andphase. For example, at medium term an aircraft separation constraint will have a more important priority than aweather turbulence constraint, whereas at long term, the two constraints may have the same priority. Moreoverthe already existing FMS constraints (such as RTA, aircraft performance limitations,...) will have to be takeninto account for the detemination of the deconflicted route.

The introduction of DMD modes, selectable by the pilot, is an approach that will be developed. For exampleduring cruise phase, in an economic mode, the priority of the aircraft separation would be larger than theweather’s one, whereas in a comfort mode, they would have the same priority. For the comfort mode, separationmaneuvers limits will be defined for enhancing the passenger comfort.

The MAS operations function will be active in the Managed AirSpaces. It will perform separation tasksdelegated by the ATC. It will receive, from the DMD, the traffic situation. Also during MAS operations theTWG separation function will work at least partially.

The Taxi management function will not be active during the flight phase therefore it will be implemented as a« standalone » process. It will exchange data with the FMS, the communication applications and will providedata directly to the EFIS.

A system-level functional block diagram incorporating the above design considerations and terminology isprovided on the next page.


3FMS PROJECT 7

ATC SimulatorTraffic Simulator

Aircraft Simulator(HMI/EFIS)

FMS

Conflict Detection and Resolution Taxi Mana

gement

WeatherDetection

GeographicDetection

TrafficDetection

Communication Applications

Display Interface

3FMS PROTOTYPE

TWG Separation

Figure 3 - 3FMS Overview

Strategic and Tactical functionIn the scope of the 3FMS project, the TWG separation function will be a tactical function that is time-related toAir Traffic Control. It is worth noting that the Safety Net is out of the scope of 3FMS (co-ordination will betargeted with the ISAWARE Project).

In the scope of 3FMS the following distinctions have been considered and applied.

OPERATIONTIMESCALE

TRAFFIC WEATHER GEOGRAPHIC PERFORMANCE

StrategicTrajectoryManagement

More than fewminutes up toseveral hours

InitialFlight Plan+Revisions



Route of Preference(FFAS) or bestATC Cleared Route(MAS)

TacticalTrajectoryManagement

Few Minutes(typically<10mn)

SeparationManoeuvres



Best Changes ofRoute (FFAS) orbest negotiatedATCclearances(MAS

Safety Net Few Seconds(typically <30s)

Avoidance Avoidance Avoidance Flight Envelop


3FMS PROJECT 8

The 3FMS role can be summarized by :

• at a strategic level the FMS computes an optimized 4-D trajectory from current aircraft positionthrough to arrival runway threshold on the basis of flight plan data uplinked by AOC,

• at a tactical level the 3FMS ensures the TWG separation and computes the corresponding optimizedtactical trajectory.

Task

Output

Goal

Ensure separation

Best Deconflicted Trajectory

Safety and cost

Avoid collision

Avoidancemanoeuvre

Safety

Optimise cost

Preferred Route

Cost

Real time Tactical Strategic30" 10’ Time

3FMS TWGSeparation

Figure 4- 3FMS role definition

Interaction with the FMS

The NEW FMS for AIRBUS contains both Sextant and Smiths functions which resides on two modules: IDPand FMP (the FM Core). The functionality important to 3FMS is split between the modules as follows (otherNEW FMS functions are omitted for clarity):

IDP

Real timefunctions

I/F to Comm s.Workstation

I/F to EIS/CD TI

FMP

Flight planm anagement

functions.

IDP -FM PM essage set

Figure 5- 3FMS implementation within the NEW FMS

The functions within the FMP are initiated by a request from IDP, although these functions can have majoractivities such as building a complete flight plan.

The 3FMS functions will need to access functions and/or data within FMP in order, for example, to provide thebest deconflicted route. All accesses to FMP will be managed by IDP.

The 3FMS functions which need to communicate with the FMP will exchange data with the functioncalled FM Core Interface.


3FMS PROJECT 9

The FM Core Interface performs the whole of the IDP/FMP interface. The architecture is based on a client-server architecture where IDP is the client and FMP the server. All requests are at the initiative of the client.

3.2.2 3FMS FUNCTIONAL BLOCK DIAGRAM

The general functional architecture of the 3FMS demonstrator and the 3FMS functions architecture are depictedon the two next pages. Each function is further described in the reminder of this section.


3FMS PROJECT 10 FDD_version_9b.doc

A/C Simulator

Traffic Simulator

ADS-B

Weather Situation

Traffic Situation

Geographic Situation

Air/GroundCommunication

CPDLC

TIS-B

Air/AirCommunication

ADS-B

ATC Simulator

TIS-B

CPDLC

FIS

Data Management

and Detection

NavSensor

and

A/CSimulations

EFIS

Simulation

PFD

MCDU

DCDU

ND+FCU

Taxi Management

FMS

MCDU

EFIS

FM Core

Interface

I/O

FM Core

NavDB

HMII/F

MAS operations

3FMS functions

TWG Separation

Air-Air DataLink

FIS

Conflict Resolution

Figure 6- 3FMS demonstrator architecture



A/G Com

A/A Com

Taxi Mngt

TWG Separation

HMI I/F

MAS Operations

ATC Simulator

A/C Simulator /

DCDU

Traffic Simulator

A/C Simulator / EFIS

FMS/ EFIS

FM Interface

FMS

CPDLC messages

ownship pos

trajectory, F-PLN

& perfo

ownship trajectory

ADS-B reports

traffic data

itemsTIS-B & FIS messages

CPDLC

ownship pos

traffic data items

route data

4D routeData iems

requestsitems

requestsitems

Figure 7 - 3FMS Functions architecture

3FMS Functions

FMSATC

Simulator

Traffic Simulator

A/C Simulator



3.3 TWG SEPARATION FUNCTION

3.3.1 OVERVIEWThe purpose of the TWG Separation function is to collect information on the airspace surrounding theownship throughout the duration of its flight and to make use of it to maintain separation from knownhazards. The hazards are grouped into three categories: Traffic, Weather and Geographic (TWG).

The function is also required to manage these data and make it available to the HMI function.

TWG Separation can therefore be divided into five other functions:• Traffic Situation• Weather Situation• Geographic situation• Data Management and Detection (DMD)• Conflict Resolution (CR)

The HMI function is described elsewhere.

DataManagement

andDetection

ConflictResolution

HMIInterface

FMInterface

List of Data ItemsRequests

List of Data Items

Data Items

Data Items

Data Items

TrafficSituation

WeatherSituation

Geog.Situation

Ownship Route

Fixed Data

A/A Comm

MASOperations

List of Data Items

A/G Comm

A/G Comm

A/G Comm

TaxiManagement

List of Data ItemsHMI

Interface

FMInterface

4D Route

4D Route

FMInterface

Services

Figure 8-TWG separation functions architecture

The structure of the TWG Separation function is shown above.

The TWG situation functions collect appropriate data and provide it to the DMD function.The DMD function will detect conflicts. The CR function will produce a new trajectory as appropriate.The DMD function will manage TWG data and conflict/trajectory data and make them available to the HMI.



The five functions that constitute TWG Separation are described in more detail below.

3.3.2 TRAFFIC SITUATION

3.3.2.1 OBJECTIVES

In MAS or FFAS, the Traffic situation will enhance the situational awareness by providing data on thesurrounding traffic for traffic conflict detection purpose.

3.3.2.2 FUNCTIONAL DESCRIPTION

3.3.2.2.1 General Organization

The Traffic Situation is in charge of maintaining an updated and consistent view of the traffic situation. Thiswill be done by managing a list of the surrounding aircraft and their relative data. A surrounding aircraft isdefined as a aircraft located in the ADS-B coverage volume of the ownship. The traffic situation function hasto check the A/C are within reach of the selected ADS-B range. The traffic situation will be provided to theDMD for conflict detection.

As a result of the above descriptions, the Traffic situation function will be limited to one process which isTraffic Data Fusion.

The Traffic situation and its data exchanges with the 3FMS context are illustrated in the block diagramhereafter.The context is composed of the A/G communication application TIS-B (Traffic Information Service -Broadcast), the Air/Air communication application ADS-B and the DMD.



Traffic Data Fusion

ADS-B reportsTIS-B reports

ADS-B App.

TIS-B App.

DMD

traffic data items

Figure 9-Traffic Situation architecture

3.3.2.2.2 Traffic Data Fusion

The Traffic Data Fusion receives the ADS-B and TIS-B data from ADS-B and TIS-B communicationapplications and produces a time consistent representation of the traffic situation.The Data Fusion process is mainly data handling to put ADS-B and TIS-B messages in the same format in atimely manner.

Main Data Flow

1) Input from ADS-B Application: - ADS-B reports - TIS-B reports.

- Request for traffic data items with Search Criteria 2) Output to DMD :

- Traffic data items according to request

BehaviorData Fusion is running permanently during the whole flight and will deliver data upon request of the DMD.



3.3.2.2.3 Data structure

This chapter gives the general structure of input data flows, as well as the general data structure of the trafficdata items.

3.3.2.2.3.1 ADS-B report

RTCA Do-242 : MASPS for ADS-B, shall provide a baseline for ADS-Bcontent. This shall be expanded asrequired. Refer to ADS-B application section for further details.

3.3.2.2.3.2 TIS report

This report is coming from the ground. It is less complete than the ADS-B report. Refer to TIS-B applicationsection for further details.

3.3.2.2.3.3 Traffic Data Items

This data item type should be the synthesis of the ADS-B and TIS-B messages. It will represent the currentposition and trajectory of an aircraft. Aircraft will be located in earth-related coordinates.This data item could be composed of two main parts: one description of the aircraft trajectory and some staticinformation about its identity.The trajectory of each aircraft should take into account the navigation uncertainty given by the ADS-Bmessages.



3.3.3 WEATHER SITUATION

3.3.3.1 OBJECTIVES

From an operational perspective, the Weather Situation provides the following capabilities:

1) In MAS or FFAS, this function will enhance the situational awareness by providing data onweather.

2) In FFAS only, this function will detect if weather constraints exist for given search criteria.At least three types of weather constraints will be considered:

- high turbulence such as thunderstorms to be avoided for safety reasons- moderate turbulence to be avoided for passengers comfort improvement- icing areas


3.3.3.2.1 General organization

The Weather Situation function will be in charge of providing an updated and consistent view of the weatherconditions.

Weather information will consist of meteorological data such as wind and temperature and significantweather data such as thunderstorms, clear air turbulence and icing. The types of data and their presentationare discussed below. The following figure shows the high-level functional breakdown of the weatherfunction.



WeatherDetection

WeatherDatabasemanager

FMInterface

FISApp.

WeatherData Items

Meteorologicaldata

Significant weatherdata

FIS reports

DMD

Figure 10- Functional architecture of the weather situation function

Prior to take-off, meteorological information will be loaded by the crew through the MCDU for CLB, CRZand DES into the FM core and updated during the flight. In particular, wind data will be used by the FM coreto build the best 4D trajectory accounting for cost and passenger comfort consideration. The new FMS uses awind model to compute the forecast winds, the latter also blended with actual wind for computation of thepredicted winds. There is a requirement to keep the meteorological information used in the FM coreconsistent with the information in the DMD. This will be achieved through a specific interface.

The update of any kind of weather information is achieved through the use of Flight Information Service(FIS), simulated by NARSIM.

In the scope of the 3FMS project, the weather radar as well as other airborne sensors for the detection ofsignificant weather phenomena will be considered as separate systems. Data from these sensors will thereforenot be dealt with in the weather detection function.

The exchange of search requests and results as well as the regular update of relevant meteorological data aremanaged through the interface to the DMD.



3.3.3.2.2 Weather Detection Function

The task of the weather detection function is to supply the data that is needed for the calculation of theconflict free route, i.e. common meteorological data (wind, temperature etc.) as well as significant weatherdata.The weather function will require data from various sources. For 3FMS, these sources include flightmeteorological data loaded on the ground prior to take-off and up-linked data received from the ground, e.g.weather reports. Apart from the pre-loaded meteorological data, all weather data are received from the FISapplication.

Main Data Flow

1. Input: - requests for weather data with search criteria - meteorological data - significant weather data

2. Output: - weather data items according to request

BehaviorThis task is event driven.

3.3.3.2.3 Weather database manager

The weather database manager handles the exchange of information with the FMS interface and the FISapplication. Upon receipt of weather information from the FIS application, the database is updatedaccordingly. Meteorological data in the FM core and the 3FMS is kept consistent by sending updatedmeteorological data from the weather database manager to the FM core. Meteorological data is also sent fromthe FMS core to the weather database prior to take-off for initial loading as well as during flight regardingwind data measured by the aircraft.

Two types of weather data have to be stored: First, meteorological data defined in a grid with appropriatemesh size linked to the flight plan, and second, significant weather data. These data are described below.

3.3.3.2.3.1 Meteorological information

Meteorological data should contain the following parameters:- wind- temperature

3.3.3.2.3.2 Significant weather information

As regards significant weather data, at least three types of weather phenomena will be considered in theproject, even though further phenomena may be added later if required. These are:- Thunderstorm activities- Turbulence- Icing Icing and turbulence are reported when not associated with thunderstorm activities. In accordance withcurrent significant weather reports, the severity of the observed/forecast phenomenon may be severe ormoderate.



The format for significant weather data may be similar to the SIGMET report as defined in ICAO annex 3. Ithas to contain the geographical location, size and shape (simple to describe mathematically) which do notexist in current standards. Only weather phenomena that are relevant for 3FMS are simulated. Geometric description The weather object is described by a polygon representing an object of arbitrary size being valid for a certainnumber of flight levels. An area that is enclosed by polygon indicates the area the significant weather report applies to. This meansthat presenting the indicated area the occurrence of the described phenomenon is likely, thus representing acertain risk to aircraft safety and/or passengers comfort. This solution represents the picture the pilotcurrently gets from a significant weather report. Descriptive Information The descriptive information is similar to information provided in the SIGMET (and other significantweather) report(s). This information should include: - Time of issue and period of validity in UTC,- Geometrical description of area of occurrence- Status of observation (observed or (forecast but not yet observed)),- Movement in direction and speed (in knots or km per hour),- Changes in intensity (intensifying, weakening, not changing),

Physical characteristics are excluded as they are outside the scope of the project. An extra flag may indicatethe level of uncertainty as outlined above.



3.3.4 GEOGRAPHIC SITUATIONThe Geographic situation includes the Terrain and Airspace Detection.

3.3.4.1 OBJECTIVES

From an operational perspective, the Geographic situation provides the following capabilities:

1) This function will enhance the situational awareness by providing geographic data. 2) This function will detect if geographic constraints exist for a given trajectory and its associated

search volume.

At least two types of geographic constraints will be considered :• the altitude restrictions or limitations including MORA, MSA and Restricted or Prohibited

Airspaces• the altitude profile of the terrain


3.3.4.2.1 General Organization

The purpose of the Geographic Situation function is to analyze the relevant databases in order to find allpotential static obstacles for a given trajectory within its associated search criteria. Whenever this function iscalled, it determines and collects all relevant obstacles.

The Geographic situation function will be composed of the following three sub-functions:

• Terrain Detection

• Airspace Detection

• Geographic Detection Interface



TerrainDetection

GeographicDetectionInterface

AirspaceDetection

geographicdata items

Terrain DB Airspace DB

terrain data items airspace data

DMD

Figure 11- Geographic situation architecture

3.3.4.2.2 Terrain detection

This function responds to the requests of the geographic detection interface.One request is composed of a trajectory and a search criterion.The response is the list of terrain data items which are located in the search volume related to the trajectory.

The Terrain Detection function shall include the following capabilities:

1) a mean to easily load and update the 3FMS terrain database,

2) a data validation technique to ensure high data integrity,

3) a production and update process which takes into account the relevant regulations, e.g. theEUROCAE-WG-44 document for GCAS terrain databases,

4) a read only protection for normal operations, a read/write data access management for maintenanceoperations and a data non-corruption check when transferring data,

5) information about the height of the terrain with an appropriate resolution and accuracy,

6) a coordinate system based on the WGS84-system,

7) terrain-models with support for different resolutions and accuracies,



Main Data Flow

1) Input: request from Geographic Detection Interface2) Output: terrain data items

Behavior

Searches the terrain database for potential obstacles on request.

3.3.4.2.3 Airspace Detection

The 3FMS airspace conflict detection will be responsible for providing the pilot awareness of the airspace-restricted areas. This will be achieved by providing the pilot with visual information about the airspacerestrictions (shape and attributes). Its implementation will be decomposed into two distinct modules:

• The airspace database.• The airspace detection function.

3.3.4.2.3.1 Airspace database

The airspace database will store airspace information relative to MSA (Minimum Sector Altitude), MORA(Minimum Off-Route Altitude) and Restrictive Airspace for the airspace area in concern. The ARINC 424records will be used as source for the airspace information. This information will be loaded into the databasebefore take-off. Although airspace information is static, meaning that it does not move with time, the fact is that itscharacteristics do change with time. Restrictive Airspace may have different attributes, not all off them beingcompletely restrictive. In same cases, for example military airspace zones, crossing of the airspace may benegotiated between the pilot and the military controller, in others relative danger has to be assessed by thepilot.

3.3.4.2.3.2 Airspace detection function

This function will be responsible for detecting, identifying and retrieving information relative to the airspacerestrictions. This function will use information relative to a volume and will obtain from the database all the airspacerestrictions intersected by either the volume or the ownship trajectory. Data flow: Inputs:

• Request from the geographic detection interface• Airspace restriction data from the airspace database.

Outputs:



• Airspace data items that are within the search volume.

3.3.4.2.4 Geographic Detection Interface

When receiving a request from the DMD, this function generates one request for Terrain Detection andanother for Airspace Detection and returns the whole set of Geographic data items.

Data flow:

Inputs:• Request from DMD with search criteria• Terrain data items• Airspace data items Outputs:• request to airspace and terrain detection functions• geographic data items

3.3.5 DATA MANAGEMENT AND DETECTIONThe Data Management and Detection (DMD) function controls the flow of all detected data between theTWG Situation functions and the functions which require it. The DMD will define the search criteria foreach of the TWG Situation functions, and request information from them. The search criteria will bedifferent for each function. The DMD will request data from the Traffic and Weather functions periodically.The data from the Geographic function will be requested aperiodically in response to a specific event.

The data received from the TWG Situation functions will be in the form of obstacles. The DMD functionshall provide a number of data management functions for the obstacle data it contains. The most important ofthese is the detection of conflicts with the active flight plan. This function will happen automatically andcontinuously and will invoke the Conflict Resolution function when a conflict is detected. The definition of aconflict depends on the obstacle type.The other data management functions provided by the DMD will provide sub-sets of obstacles to the ConflictResolution, MAS Operations, Taxi Management and HMI Interface functions.Within this context the DMD function will be divided, according to the following diagram, into five sub-contexts:-

− Data Fusion− Obstacle List Manager− Conflict Detection− Request Manager− HMI, MAS, Taxi and Conflict Resolution Request



Obstacle ListTraffic

Situation

Weather

Situation

Geographic

Situation

DataFusion

Obstacle

List

Manager

FM Interface

HMI Interface Request

Manager

Conflict

Detection

HMI InterfaceHMI

Requests

MAS

Operations

MAS

Requests

Taxi

Management

Taxi

Requests

Conflict

Resolution

CR

Requests

Data items

Active Flight Plan

Request for Data and Services

Request forResolution

SearchRequests

DataLists

All Data

Request

Dataitems

SearchCriteria

3.3.5.1 DATA FUSION

This function controls the request of data items from the TWG Situation functions and provides them for theObstacle List Manager.

3.3.5.2 OBSTACLE LIST MANAGER

The Obstacle List Manager (OLM) controls all access to the Obstacle List, which stores all data itemscollected by the TWG Situation functions. The OLM receives data items from Data Fusion and adds them tothe Obstacle List. The OLM responds to search requests from other functions and returns a list of obstaclesthat meet the search criteria.

3.3.5.3 CONFLICT DETECTION

Conflict Detection (CD) requests and receives all data items from the OLM. It assesses these data items forconflict with the current active flight plan. Conflict Detection makes specific use of available functionality todetermine conflicts with the active flight plan. Upon detection of a conflict it requests a solution from theRequest Manager.

3.3.5.4 REQUEST MANAGER

The Request Manager (RM) handles all requests for information and services, such as resolutions, from theHMI and CD functions. The RM receives, interprets and manages these requests before passing them on tothe appropriate Request function at the required time.

3.3.5.5 HMI, MAS, TAXI AND CONFLICT RESOLUTION REQUEST

These functions receive simplified requests from the Request Manager. Upon receipt of the request, thesefunctions will formulate the appropriate search criteria and request this data from the OLM. The receiveddata will then be passed to the corresponding client function.Data provided to the Conflict Resolution, MAS Operations and Taxi Management functions will beautomatic or under a specific request. Data provided to the HMI function will be in response to a requestfrom the HMI. These requests provide the capability to filter data for purposes of de-cluttering the display forexample.



3.3.5.6 DMD INTERFACE

DMD Input Data

− Traffic Data Items− Weather Data Items− Geographic Data Items− Requests from HMI Interface− Active Flight Plan from FM Interface

DMD Output Data

− Traffic Search Criteria− Weather Search Criteria− Geographic Search Criteria− Requests for new searches− Lists of Data Items

3.3.6 CONFLICT RESOLUTIONThe Conflict Resolution (CR) function shall be able to solve the detected conflict by computing a conflictfree route: a route that avoids all the known obstacles. In order to evaluate a possible solution the CRfunction will make use of functionality within the FM core. Access to the FM core will be via the FMInterface function. This accessing of the FM core will ensure that the solution from the CR function is bothflyable and acceptable to the FM core.The CR function has a specific role. It must produce a route between given positions that avoids all theobstacles presented to it. Several solutions will be produced for this function and they will all conform to thesame interface. The CR function will also reside in NARSIM.The solution from CR will be provided to both the FM core and the HMI interface. This allows the pilot toreview, interrogate and accept it using existing and new HMI. The CR function shall have timing constraintsimposed upon it. The maximum time allowed will be determined from the onset of the safety net functions.The resolution route does not begin at the current aircraft position but at the defined way point ahead calledStart Of Maneuver (SOM). The SOM is proposed by the CR with the resolution route

3.3.6.1 CR INTERFACE

The input data will consist of a list of obstacles, initial conditions such as start/finish points and a number ofadditional constraints such as Cost Index, Passenger Comfort Index, etc.. This is shown below:

CR Input Data

− Cost Index (CI)− Passenger Comfort Index (PCI)− Separation standard− Ownship position and trajectory− Ownship flight envelope (e.g. alt max., Vmax, Vmin, max. vertical speed)− A/C, Weather and Geographic data items

CR Output Data

− Resolution Route Data



3.4 MAS OPERATIONS

3.4.1 OBJECTIVESFrom an operational perspective, the MAS operations function provides the following capability:

In MAS, this function will compute guidance commands subject to constraints uplinked by ATC. This willenable the FMS to be kept in the loop for all MAS maneuvers including Station Keeping .

MASOperations

FMInterface

CPDLCApp.

HMI I/FDMD

ownship postrajectory

traffic data items

CPDLC messages

FMInterface

Route data

A/C identRoute data

Figure 12 - MAS Operations function

3.4.2 FUNCTIONAL DESCRIPTIONFor each specific MAS operation, there will be a specific treatment and a specific symbology. For the onlyone which is today envisaged, Station Keeping , the specific requirements are the following ones:

Station keeping

This application will allow the ownship on its track to maintain longitudinal separation with the precedingaircraft in an in-trail stream.

On the basis of the target aircraft designation made either by the pilot or directly by the ATC throughCPDLC, the aircraft has to stay at a defined longitudinal distance from the preceding aircraft in accordancewith the separation standard and in following the lateral path of this preceding aircraft.

It requires the computation of the corresponding speed guidance command for aircraft systems and thedisplay of symbology for pilot awareness (highlight of target aircraft, warnings, ...).

This operation can include the capture and ending procedures, the latter for normal and emergencyconditions.

This operation can be flown either manually or automatically.

Data Flow



Inputs:

• Ownship position and trajectory from FM interface

• Traffic data items from DMD

• clearances from CPDLC application

• Specific commands from the HMI interface

Outputs:

• route data into the FMS interface

• route data to the HMI interface



3.5 TAXI MANAGEMENT

3.5.1 OBJECTIVESThe ultimate goal of the Free Flight concept is to support « gate to gate » operations. In such environment theairlines will be able to operate their fleet in an optimized way from the engines start up to the arrival at thegate. The Taxi Management function deals with the ground movement phase of the flight and constitutes amajor piece for the deployment of a full Free Flight concept. The expected benefits include reduction of taxitime specifically in low visibility conditions without comprising safety.

The Taxi Management function will cover the following flight segments

• at the departure airport, from push back up to the take-off runway (thrust pushed and speed lessthan 60 kts)

• at the arrival airport, after landing (A/C on ground and speed less than 60 kts) up to the arrival gate.

A ground situational awareness (during taxiing phase only) will be provided by the ND. It will basicallyinclude a presentation of the aircraft position, a track in taxi chart and a runway incursion warning.

In the frame of 3FMS the Taxi management function will be seen as the onboard part of a future SurfaceMovement Guidance and Control System (SMGCS).

SMGCS overview

SMGC is the attempt to ensure safety of airport surface traffic under growing traffic density and all weatherconditions and to improve efficiency of airport operation in the view of limited resources. SMGC isaccomplished by co-operation between the A/C and the Ground.

Figure 13- SMGCS overview

In a full SMGC environment the ground part of SMGC offers support in surveillance, planning and guidance.The traffic situation is presented, the traffic flow can be planned, monitored and co-ordinated and theguidance information, finally, can be transferred to the aircraft or the airport vehicles by an automatic control

Communication with SMGCSSituation Awareness DisplayTaxi Guidance / Monitoring

Automatic Taxiing

SurveillanceSensors Datafusion, Traffic Situation Presentation

PlanningTraffic Flow Planning, Traffic Flow Monitoring, Coordination

with Airlines and Airport Planning Systems

GuidanceTransfer of Guidance Information to the Aircraft

Control of Taxi Lighting System

Taxi ManagementOnboard part of SMGC

Uplink(Taxi Route, conflicts)

Downlink(Position, Velocity, Requests)

Ground part of SMGC



of the ground based taxi lighting systems. From this ground part of the SMGC the cleared taxi route orpossible conflicts can be uplinked to the taxi management system onboard the aircraft. For that purpose, theonboard equipment as well as the ground system have to support suitable data link communications. Theground system (SMGCS) has to be provided by the airport authorities.

The onboard taxi management system uses this information to display the cleared route on the ND and toassist in this way the pilot during the taxiing procedure. In future applications onboard taxi guidance evenenables a fully automatic taxiing leading to significant improvements in all weather operation on ground andthe guidance accuracy needed for ultra-high capacity aircraft (A3XXTo support the ground part of SMGC thetaxi guidance system must be able to downlink the aircraft position and velocity as well as certain requests(for push-back, taxi clearance and so on). This downlink capability enables the ground based SMGC tocomply with all the functions just explained.

3.5.2 FUNCTIONAL DESCRIPTION

3.5.2.1 GENERAL ORGANIZATION

In the Scope of the 3FMS project the Taxi Management function will be considered as a sub-system thatinteracts with the 3FMS Core.

In the frame of the 3FMS project a ground SMGCS will not be available. By making use of an ATC and aTraffic simulator, however, Controller-Pilot Data Link Communications (CPDLC) and a generation of thesurrounding traffic can be realized. The realization of these two main data communication features issufficient in order to demonstrate and validate the aircraft taxi management capabilities at the full extent.

Therefore, the following baseline capabilities will be developed to demonstrate and validate the TaxiManagement function:

1. The traffic simulator will be capable to generate surrounding aircraft traffic on ground2. The ATC simulator will provide a set of CPDLC messages related to ground movements3. CPDLC messages will be displayed on the DCDU4. A highly accurate aircraft position will be available from the A/C simulator5. A display window on the ND will be provided in the A/C simulator6. New symbols will be generated by the EFIS simulation7. The necessary airport databases will be implemented8. The necessary Taxi chart will be implemented

As a baseline and in order to identify the proper taxi route to the gate or to the runway, a map of the airportarea will be displayed with selectable ranges and alignments. The position of the aircraft and the taxiclearance will be superimposed on the map. The taxi clearance is transmitted by ATC via datalink and isshown on the display as illustration as well as in plain language. An appropriated color coding specifies thecleared route and the clearance limit. Additional steering information, such as heading, ground speed,respective (voice) ground frequency is presented on top of the display.

The presentation of active A/C traffic with its current ground speed indications gives information about theintention of the surrounding traffic, including landing A/C and enables the crew to adjust spacing during taxioperations.

Several warning and alerting functions issued in case of any deviation from the clearance or ATC advisorieskeep the crew involved in the actual situation and contribute to an improvement in flight safety.



An implemented steering guidance (passive) supports the crew during taxiing in low visibility. Finally thebuilt in self test and the warning function for a system fault assures the required functionality during taxioperations.

Taxi MngtDisplayInterface

Taxi Mngt

DMD

CPDLCApp.

FMInterface

A/CSimulator

Airport DB

CPDLCmessages

Trafficdata items

a/c pos

CoreModule

Figure 14- Taxi management architecture

3.5.2.2 TAXI MANAGEMENT FUNCTION

The Taxi Management function will be composed of three sub-functions:- the airport data base- the taxi management core module- the taxi management display interface

3.5.2.2.1 Airport Database

An airport database including highly accurate terminal area maps that contain runways, taxiways,intersections, gate locations and other pertinent data will be developed for the implementation of the TaxiManagement function.

Behavior

A data base management module including data handling utilities will be integrated in the Taxi Managementcore module.

Data Structure

A specific database format derived from the Daimler-Benz’s Geographic Data Files standard (GDF version2.1) will be used. The GDF format defines a data structure and a data exchange format which support theconstruction of geographic road.



For the 3FMS project, extensions will be developed as well as new features (like runways, taxiways orparking positions) and new attributes (like identifier, surface or gradient for a runway). With this extendeddata structure the layout of the airport operational areas will be accurately described. All location informationin terms of latitude and longitude will be referenced to the World Geodetic System (WGS) 84.

3.5.2.2.2 Taxi Management core module

The taxi management core module is responsible for the control and coordination of the taxi managementfunction. It manages the access to the airport database and realizes the interfaces with the other modules ofthe 3FMS.

Main Data Flow

1) Input absolute position (latitude, longitude) ground speed actual heading CPDLC messages Traffic information 2) All other interfaces to and from the taxi management core module are realized internally with the airportdata base and the taxi management display interface.

Behavior

The taxi management core module will use absolute position (latitude/longitude) with respect to the WGS-84reference system, ground speed and actual heading from the navigation function of the core 3FMS.

Besides the aircraft state data all relevant data link messages are handled in the taxi management coremodule. This covers the taxi related CPDLC messages as well as the traffic information. In case a taxiclearance is received from the respective message store the taxi management core module will add theclearance information to the respective airport map elements (for example taxiway Charlie is marked ascleared). This information is then passed to the taxi management display interface for the presentation of theinformation to the crew.

3.5.2.2.3 Taxi Management Display Interface

3.5.2.2.3.1 Presentation

The display shall be able to present all supported airport surface maps, which can be utilized to navigate theaircraft along the airport surface in both VMC and low visibility conditions. Therefore the Taxi ManagementDisplay Interface shall provide an airport surface map including the following items.

• taxiways with identifier• guidance lines• CATII/III stopbars• runways with identifier at each end• markings of the runways• edges of the runways and the taxiways• airport buildings (only outlines) with identifier• parking positions with identifier



• guidelanes for parking positions with identifier

Based on the determined aircraft position and the airport database the airport surface map shall be displayedon the EFIS display during taxi operation with the current position of the aircraft overlayed. In general thepresentation of the taxicharts on the display shall be very similar to the Jeppesen taxicharts.

The airport map shall be displayed with selectable ranges (discrete). The maximum range shall cover thewhole airport. The minimum range shall be 300 ft.Presentation detail shall depend on the selected range.

For surface map presentation the following display modes shall be selectable:• HEADING UP• TRUE NORTH UP

The following aircraft data (own A/C) shall be shown on the display:• position (showed by an aircraft symbol)• heading• ground speed

A ground-trajectory (recommended taxiroute) shall be overlayed on the display, i.e. the cleared part of thetaxiroute shall be presented green. Question : How will be built this route : by the crew by interaction on thedisplay? from a list in database? A mix ? by datalink?. The ongoing taxiroute shall be indicated red. If theclearance limit is the final parking position, the parking position including its identifier is also shown(irrespective of selected range).Active stopbars shall be indicated red.A/C traffic with speed indication (relevant A/C traffic to be specified) shall be presented on the map.

In addition the following information shall be presented:• CPDLC messages• alphanumeric presentation of the actual and next intersecting taxiway• frequency for voice communication - ground-apron• range indication• chart orientation (heading up/true north up)• alerting messages

Steering guidance shall be displayed on the PFD. The rollbar of the flight director is used to indicate therequired input on the steering wheel. The airborne function of the flight director is reactivated automaticallyby exceeding a specified position of the thrust lever at take off, as it is already implemented in Airbus planes.

3.5.2.2.3.2 Alerting

When a clearance or a revised clearance has been transmitted by ATC, the new clearance is automaticallypresented on the display while a single aural signal advises the crew that a new message is received.

When the aircraft is passing a stopbar without a clearance the equipment shall provide the following alertingfunctions:• the respective stopbar represented on the display starts to blink• a warning shall be displayed on the display• an aural warning is broadcasted by voice, e.g. “stopbar”

In case of a runway incursion an alerting message shall be presented.



When the aircraft deviates from the cleared route – deviation in this case is meant to be all others thanrunway incursion and passing stopbars. e.g. another route – the taxi management function provides thefollowing alerting functions.• an aural signal of the first level shall be broadcasted permanent• an aural warning is broadcasted by voice, e.g. “deviation” or “route”

An implementation of a so called « ROGER » function to acknowledge warnings shall be provided by theequipment.



3.6 FMS INTERFACE

3.6.1 OBJECTIVESFrom an operational perspective, the FMS Interface function will be involved in all the operational goals ofthe 3FMS.

3.6.2 FUNCTIONAL DESCRIPTION

FMSInterface

ADS-BApplication

TaxiManagement

DMD

MASOperations

ConflictResolution

FMS

WeatherSituation

Figure 15 - FM Interface function

The FMS Interface function will be in charge of centralizing and updating data from the FMS and providingthem to the 3FMS functions. It will also be the mean for 3FMS functions to send data to the FMS.The FMS interface is a two ways data buffer between FMS and 3FMS functions. It is the only 3FMSfunction that will exchange data with the FMS.

Data Flow

Inputs from the FMS:

• Ownship 3D position

• Flight Plan

• Ground Speed

• Heading

• Ground Track



• Turn rate

• Vertical Speed

• Accuracy of preceding data

• Cost Index

• Ownship envelope (max. altitude, Vmax, Vmin, max. vertical Speed,...)

Inputs from 3FMS functions:

• From Conflict Resolution : 4D route

• From MAS Operations : Route data

Outputs to 3FMS functions:

• To The Taxi Management function : Ownship position, Ground Speed, Heading

• To the ADS-B application : Ownship 3D position, Flight Plan, Ground Speed, Ground Track, Turn rate,Vertical Speed, accuracy of preceding data

• To the MAS Operations function : Ownship 3D position, Flight Plan

• To the DMD function : Ownship 3D position, Flight Plan

• To the Weather Situation : Meteorological data

• To the Conflict Resolution function : Ownship 3D position, Flight Plan, Cost Index, Ownship envelope(max. altitude, Vmax, Vmin, max. vertical Speed,...)

Outputs to FMS:

• Flight Plan data

3.7 COMMUNICATION APPLICATIONS

The primary objective of 3FMS is to develop and assess functions related to Free-Flight FMS thereforecommunication software for the 3FMS demonstrator will be developed when required or provided by COTSsoftware. It is worth noting that some real time characteristics for communication are not strictly mandatoryin the scope of 3FMS.The main role of communication applications is to assure the proper interface with the Traffic and ATCsimulator and to dispatch the exchanged data to all the 3FMS module.

3.7.1 AIR/GROUND APPLICATIONS

The following figure shows the high level flow of the airborne Air/Ground communication applications.



TIS-BApp.

FISApp.

ATC Simu/ CPDLC

A/C Simu /DCDU

MASOperations

Traffic Simu

/TIS-B

TrafficSituation

TaxiMngt

ATC Simu/ FIS

WeatherSituation

CPDLCApp.

CPDLCmessages

CPDLCmessages

CPDLCmessages

TIS-Bmessages

TIS-Bmessages

FIS reports FIS reports

CPDLCmessages

Figure 16- Airborne Air-Ground communication architecture

3.7.1.1 CPDLC APPLICATION

The CPDLC application provides the capability to establish, manage, and terminate CPDLC dialoguesbetween ATS ground and aircraft.

This function shall be capable of handling the following messages:

A. general information exchangeB. clearance

1. delivery2. request3. response

C. altitude/identity surveillanceD. monitoring of current/planned position



E. advisories1. request2. delivery

F. system management functionsG. emergency situations.

The CPDLC application will be in charge of providing CPDLC messages exchanges between the ATCsimulator from one part and the DCDU or the MAS Operations and taxi management functions from anotherpart.

This application will also manage the message display and handling of the DCDU.

3.7.1.2 TIS-B APPLICATION

The Traffic Information Service (TIS-B) is based on surveillance ground-based systems that broadcast trafficinformation for a given area. This service will allow non ADS-B equipped aircraft to be seen by otherstraffic. It will operate during the transition phase.

The TIS-B application will be in charge of receiving TIS-B reports from the Traffic simulator and forwardingthem to Traffic Situation function. TIS-B data is shown below.

Call sign

Address Mode S address

State vector

• 3D position

• 3D velocity vector

• Position uncertainty category determine integrity and accuracy of the reported position

• Velocity uncertainty category determine integrity and accuracy of the reported velocity

3.7.1.3 FIS APPLICATION

The FIS application is designed to enable FIS services to be provided to a pilot via the exchange of messagesbetween aircraft avionics and FIS ground systems.

The FIS application will be in charge of receiving FIS messages from the ATC simulator and forwardingthem to Weather Situation function.



3.7.2 AIR/AIR APPLICATIONS

3.7.2.1 ADS-B APPLICATION

3.7.2.1.1 Background

Automatic Dependent Surveillance - Broadcast (ADS-B) is a new aviation surveillance concept wherebyaircraft transmit their positions (derived, for instance, from a Global Navigation Satellite System (GNSS)receiver on board the aircraft) over a radio datalink. Position information is transmitted and received by everyaircraft in the vicinity, so all users have knowledge of the other surrounding aircraft. The positioninformation may be displayed in the cockpits of suitably equipped aircraft to give new location awarenesscapabilities. These information include the aircraft identity and velocity and most importantly some tacticalparameters as trajectory change points or target values.

Pilots inputs

Navigationsensors Applications

Barometricaltitude

Applications

ApplicationsMessagesgeneration

Messagesreception

reportsconceptionE

mis

sio

n

Rec

epti

on

Medium

Source sub-system

Source sub-system

Figure 17- ADS-B system

ADS-B should not be confused with common ADS. With ADS-B, an aircraft regularly and frequentlytransmits its position to all surrounding users, whether they are ground-based or airborne. With the commonADS, the aircraft only transmits its position to a single ground center with lower frequency, and as often asrequired by that ground center.

3.7.2.1.2 Functional description

ADS-B

FMInterface

TrafficSimu /ADS-B

TrafficSituation

a/cposition

ADS-Bmessages

ADS-Bmessages

Figure 18- ADS-B system architecture



The ADS-B application is required to receive ADS-B reports from the Traffic Simulator and send them to theTraffic Situation function.

This application is also in charge of sending outcoming reports. For this purpose, it will receive data from theFM interface about the FM position and the current trajectory, then it will elaborate ADS-B reports and sendthem to the Traffic Simulator.

The ADS-B application is running permanently during flight including the taxi phase.

3.7.2.1.3 ADS-B reports description

The ADS-B Reports will contain:

Call sign

Address Mode S address

A/C type

State vector

• 3D position

• 3D velocity vector

• Rate of turn

• Position uncertainty category determine integrity and accuracy of the reported position

• Velocity uncertainty category determine integrity and accuracy of the reported velocity

Status and intent information

• Emergency/priority status (normal, General emergency, Minimum fuel, No communication..)

• Current trajectory changepoint (TCP)

Note 1

• Trajectory change point + n Note 2

Class code indicate the capability of an aircraft to support specific operationas Station Keeping or free flight

Other information For example, information required for resolution coordination

Note 1: The TCP is the point in three dimensional space where the current operational trajectory is planed to change

and the estimated remaining flight time to that point. The TCP is defined as four elements consisting of thefollowing:• Latitude• Longitude• Altitude• Time to go

Note 2:



The number of required TCP should be high enough to allow the Conflict Detection to predict the trajectory forthe entire look-ahead time period.

3.7.2.2 AIR/AIR DATA LINK

A/A DL TWG SeparationTraffic Simu

addressed messages

addressed messages

Figure 19-Air-Air DataLink function

This application shall allow the TWG separation and the Traffic Simulator to exchange data for air/aircoordination. The exchanged messages will be addressed.



3.8 HUMAN MACHINE INTERFACE

3.8.1 INTRODUCTION / ASSUMPTIONS

3.8.1.1 INTRODUCTION

The 3FMS is first of all a normal FMS with the standard flight planning and flight management functions. Inaddition the 3FMS includes ASAS functions and terrain, airspace and weather separation functions. As far asthe HMI function is concerned, new requirements have been identified. They can be declined as taskrequirements.Operating in a free flight environment will require a change in the crew tasks. Such a change in task willrequire modifications to the currently used HMI. Based on the current Airbus family cockpit designphilosophy, some elements, display and/or control will have to be introduced.

3.8.1.2 HMI FUNCTION

The HMI function can be described by the following flow chart:

HMIManagement

CR

DMD

MAS

DisplayControl &

Logic

VISUND + VD

F/C IF

Alert

4D Route

Data items

A/C ident +Route data

Alert request /Alert cancel request

Accept route change

HMI request /HMI items

TWG separation

HMI filter item

Figure 20 -HMI interface function



The HMI Management module is in charge of generating/acquiring data to/from flight crew interfaces. Thosemay be:- EFIS to display TWG information- Alert : to provide the crew with caution / advisory when a conflict is detected- F/C Interface : to enable the flight crew to accept/reject a route modification proposal, … (MCDU or

Cursor Control Device)The Display Control & Logic module stands for the function enabling to modify display range, to filterinformation (e.g. display only some selected meteorological phenomenon), …

Main data flow

- Inputs :- From CR : 4D Route (resolution route)- From DMD : Data item (traffic, geographic, weather items)- From MAS : A/C ident and route data- From FMS/EFIS : HMI request- From A/C simulator : Alert cancel request, HMI filter data item

Note : HMI filter data items stands for the flight crew controls on HMI (e.g. selection of display volume,selection of items to be displayed, …) - Output :

- To DMD : request for HMI- To MAS : A/C ident and route data- To FMS/EFIS : HMI items- To A/C simulator : alert request (e.g. advisory or caution for a conflict, …)

3.8.1.3 PILOT WORKLOAD

In all phases of the flight and especially in FFAS, the new HMI should reduce the global pilot’s workloadand not increase it.The HMI has to be defined so that the pilot will not stay too long ‘head down’ in the cockpit and that he willbe aware of the outside environment.

3.8.1.4 GENERAL ASSUMPTIONS

The HMI will be based on the following hypothesis:- The ASAS operation should be routine-minded. There exist certified procedures, certified systems, and

the flight crews and Air Traffic controllers are qualified and receive proper training to cope with bothnominal and adverse situation. In particular, same procedures will apply to all A/C involved in a sameconflict.

- The ACAS and the GCAS systems exist as a safety net in the 3FMS project but their HMI / functionalitywill not be studied here. In nominal situation, only ASAS traffic display and alert are presented to theflight crew. There is a need of compatibility between the new ASAS symbology and the ACAS one forthe traffic display and moreover a total integration between ACAS and ASAS (e.g. : to avoid duplicationof some alerts / symbols) even if in the 3FMS project the ACAS information is not displayed.

- ACAS information are supposed to be displayed only in case of- Existence of a very short-term conflict- Important dissimilarities between ACAS and ASAS data as seen by ACAS

- As far as communications are concerned, only uplink messages (and their associated response) are in thescope of 3FMS project.

- The flight crew shall have the capability to be aware of Traffic, Weather & Geographic information allalong the route to anticipate situation and monitor automatic systems.



3.8.1.5 GENERAL HMI REQUIREMENTS

The following requirements shall be taken into account- The system has to be fully managed even via the FMS or manually. The whole-intended FMS route has

to be flown as defined as it is broadcast to other A/C and ATC.- The guidance shall be nominally automatic in FFAS including Step alts.- A Vertical information additional to the Navigation display dedicated to the lateral part shall be installed

to improve the knowledge of the situation, the understanding of one conflict, and the validation of aresolution.

- The flight crew shall be informed of the loss of free flight function, to take appropriate proceduralcorrective action (e.g. avoid the entry in FFAS, get out of the FFAS, contact ATC via voice etc.)

- Different levels of alarm for the different conflict shall be installed (e.g. cautions, advisories)- Separate display options shall be provided for each TWG function. It can be necessary to mix some of

these functions.- The flight crew shall be able to check and modify display volume. They shall be able to check and

modify search and/or alert volume upon ATM request. They shall be able to modify surveillanceparameters.

- It is assumed that for optimal efficiency, the HMI will use direct interaction with the flight deck screens(for example use of a Cursor Control Device has to be defined and validated).

As far as Air/Ground communications are concerned:- The system shall provide flight deck annunciation of messages, flight deck control capability, and flight

deck display capability.- The flight crew shall be able to manage, operate Data Link while conducting normal aircraft operation:

the display of CPDLC messages shall be done on a dedicated interface (e.g. DCDUs).- In the frame of EPOPEE trials, the loading of clearances (in MAS) into a system will not be possible.

3.8.2 FFAS OPERATIONS

3.8.2.1 TRANSFER CONTROL

ATC will be fully active in MAS and before transition to FFAS. In FFAS ATC will monitor the situationknowing that ATC is aware of all aircraft position and situation everywhere (even above the oceans). Theflight crew will need to accept responsibility for separation when allowed to enter into FFAS and will need tohand responsibility back to ATC upon entering MAS.For that purpose, the flight crew shall be able to receive dedicated transition clearances via datalink (refer toA/G communication section).The flight crew shall be provided the capability to activate and deactivate on-board ASASfunctions.

3.8.2.2 MONITORING OF NAVIGATION RELATED PARAMETERS

The flight crew shall be able to monitor RNP / EPE (or FOM: Figure Of Merit :). They shall be informed incase of loss of RNP.The flight crew shall be informed of RTA / ETA at FFASexit point.The flight crew shall be able to modify a conflict resolution criterion. This may rely on Cost Index /Passenger Comfort Index / and-or other TBD.

3.8.2.3 MONITORING OF FLIGHT PLAN

The flight crew shall be able to monitor their active flight plan i.e. check that it is :- 'Traffic safe'- 'Geographic safe' (i.e. that it both avoids terrain and prohibited areas)- 'weather safe'



3.8.2.4 ROUTE OF PREFERENCE

3.8.2.4.1 Route selection

The flight crew has to be kept in the loop of the all route selection process.They need to be able to select the route proposed by the system and to select an appropriate decision (accept,reject, modify, …).As a baseline, one route proposal only shall be provided to the pilot. The algorithm is supposed to computethe optimized route with all defined criteria. In the case where two or more routes are provided, it may be notinteresting for the pilot to chose one because this will increase greatly the workload.

3.8.2.4.2 Assess risk

At all times and especially when first notified of a need to make a decision, the flight crew will need to assessthe risks associated with the situation and also to understand any constraints that are imposed on his freedomto make a decision. So they will need to check the suitability of the proposed route with regards to suchconstraints as winds, geography (fees, …), ETA/RTA, …They shall therefore be provided with the relevant information.Note :the first studies show that the raw data are generally needed in order to validate the route and take thedecision.

3.8.2.4.3 Route modification

The pilot must have overall control on the route to be flown and check all important parameters. He shalltherefore have the capacity to modify the route proposed by the automation, prepared by some other party(e.g. AOC, ATC) or his own active route.Whenever a route is modified by the flight crew, it shall be displayed.

3.8.2.5 COMMUNICATION/ NEGOTIATION

The pilot is always in the decision loop and has the capacity to modify solutions to a given problem. Aftermaking his decision, he must be able to communicate to ATC, other A/C, etc. . He may be involved morethan just accepting or rejecting to cope with abnormal situation.The pilot may require additional information, or wish to clear a given maneuver, with other A/C for example,before implementing it. Such negotiation may also be required for some separation algorithms. The pilotneeds to have a clear representation of his own trajectory and the other A/C or environment before decidingto accept or reject the route.

3.8.2.6 TRAFFIC REQUIREMENTS

Regarding traffic, or ASAS to be more specific, the following functions are provided towards the crew:- Presenting the traffic situation from DMD inputs + pilot display selections- Detecting traffic conflicts- Calculating the best resolution manoeuvre in case of a conflict (criteria to be agreed)- Allowing execution of the resolution manoeuvreHMI is involved in all those steps as described hereafter.Note :Each of these functions is new and requires involvement of the crew. Because the importance of thesefunctions the HMI to the crew needs particular attention.

3.8.2.6.1 Presenting the traffic situation

ASAS will have its impact on the navigation and surveillance tasks of the crew. An initially planned flightplan will need to be modified due to the existing traffic situation.For this reason the traffic situation shall be presented on the navigation display.



Note: The altitude profile is not presented graphically but only alphanumerically available on the MCDU.When flying under ATC control the altitude profile of a flight is to a very large extend determined by ATCclearances. In a free flight situation however the vertical profile becomes fully a crew responsibility and willrequire attention in the navigation display design.The vertical situation shall be presented to the flight crew on a Vertical Display.The HMI shall provide information about minimal separation between ownship route and other A/C route.The HMI must be able to display surveillance parameters such as Flight Ident, Altitude under adequate form(relative / absolute), Relative Bearing, etc.

3.8.2.6.2 Detecting traffic conflicts

Conflict shall be automatically detected by at least one of the A/C involved.The detection of traffic conflicts needs to be obvious, unambiguous. Detected conflicts needs to be presentedin a way that the 3D situation is clear to the crew.Note : The vertical presentation of the conflict with respect to the vertical situation will be of importance incase of conflict resolutions by altitude change.The flight crew shall be alerted of a potential conflict. All flight crews shall be alerted at the same time sothat they may efficiently communicate if required.The flight crew shall be informed of the conflict parameters.

3.8.2.6.3 Calculating one resolution maneuver in case of a conflict

After a conflict has been detected the CR function will calculate one possible resolution maneuver. Themaneuver can be lateral, and/or vertical and/or in time (speed). This presentation is again of importancebecause there is a time constraint on the crew to interpret and to select the solution. This time constraint isdetermined by the moment the conflict has been detected, the time needed by the CR to calculate a solution,the time required to perform in order to solve the conflict and by the minimal time allowed between solvingthe conflict and the occurrence of the loss of separation or ACAS alert.Note : In the following section, it is considered that the term resolution applies to the resolution for each A/Cinvolved.

The resolution ( Resolution = Resolution for A/C1 + Resolution for A/C2 + …) itself must be computed andAGREED by both A/C consensually, quickly, AUTOMATICALLY (including : who modifies the trajectoryand how) .When the resolution is computed, the both resolution trajectories shall be presented to both crews.Note :the decision that only one A/C or both modify the Active Flight Plan is to be taken from variouscriteria like safety, robustness, passenger comfort, efficiency… and therefore will depend on the algorithmsand cannot be stated hereOnce the resolution is defined, it shall be presented to both crews at the same time for- correct understanding- anticipation of future operation INCLUDING THE PURSUING OF THE MISSION and- for validation, because the crew validation is necessary each time the Active Route is modified- a good way to efficiently involve them- Except when only one aircraft is planned to maneuver, it is not worth presenting several solutions as a

nominal operation because this is highly workload demanding compared to possible benefits. Only thebest solution shall be presented to the flight crew.

The presentation of the solution shall enable the flight crew to check, at a glance, that:- The conflict is resolved- No new conflict is triggered- The proposed trajectory is compliant with geographic and weather constraintsThe flight crew shall be able to check impacts on the pursuing of their mission.



Nominally, conflicts resolutions shall not demand crew co-ordination.

3.8.2.6.4 Accepting and executing the resolution maneuver

As described above the CRwill provide one solution to solve a conflict. The flight crew shall be able tovalidate both the resolution and (for the ones involved) the trajectory modification on a single action.The crew must be able to refuse the automatic resolution and build (possibly from the automatic resolution)another Flight Plan ; due to consequences on A/C co-ordination, this must be VERY EXCEPTIONAL (e.g. incase of absence of automatic resolution)

3.8.2.7 WEATHER REQUIREMENTS

As for traffic, regarding weather, HMI functions are provided towards the crew during the following steps:- Presenting the weather situation from DMD inputs + pilot display selections- Presenting weather conflicts- Calculating the best resolution maneuver in case of a conflict (criteria to be agreed)- Allowing execution of the resolution maneuverWeather information available on board the aircraft consists of two main parts. First there is the grid winddata which includes the wind speed and direction at several altitudes at grid positions covering an area ofinterest. This wind data will be updated via data link and will not require crew involvement. The second partwill consist of significant weather phenomena. This includes phenomena like thunderclouds, turbulence areasetc. They are defined by the area of occurrence and the type of phenomena.

3.8.2.7.1 Presenting the weather situation

Significant weather phenomena shall only be presented if relevant for the flight phase which means at leastfiltering based on altitude and crew selection.The crew shall be able to select / deselect options allowing to display all the specific kinds of weather andadditional information as needed.

3.8.2.7.2 Detecting weather conflicts/incursions

As it was mentioned for traffic detection and presentation, the presentation of a weather conflict shall beunambiguous. This means that a weather conflict should never be confused with a traffic or geographicconflict.The type of phenomena shall be immediately identified to the crew.Note :The latter is of importance because the crew might decide to take no action in case of a detectedweather conflict (e.g. if the crew decides that the phenomena is not severe enough to initiate a maneuver)The flight crew shall be informed of the conflict both on the ND and VDThe flight crew shall be able to remove a phenomenon from the resolution process if he believes that theinformation is wrong.


In case a conflict has been detected the CR will calculate a separation maneuver. For this separationmaneuver the same applies as for traffic separation with the main difference that no air/air consensus isneeded. Moreover, the velocity of the counterpart is far less in case of weather conflicts.The flight crew shall be informed of the computed resolution. They shall be able to check that:- The solution is compliant with geographic, and traffic constraints- It is correct with regards to mission parameters (fuel, RTA…)

3.8.2.7.4 Executing the resolution maneuver

Similar to the traffic separation the CR function shall provide one maneuver.The flight crew shall be able to accept / reject / modify the automatic resolution.



3.8.2.8 GEOGRAPHIC REQUIREMENTS

HMI is involved in the following steps:- Presenting the geographic situation- Detecting geographic conflicts/incursions- Calculating one resolution maneuver in case of a conflict- Executing the resolution maneuver

3.8.2.8.1 Presenting the geographic situation

Geographic situation includes not just terrain but also the airspace structure defining the free flight airspace,managed airspace and special use airspace. Terrain obviously does not change in the course of the flight, butthe airspace structure can change during the flight. Parts of managed airspace can be converted into freeflight airspace and vice versa. Special use airspace can be made available or be declared prohibited for acertain period of the day. This means that geographic situation (including airspace) has its owncharacteristics compared to traffic and weather. It might not move but it is not stationary as well.The GCAS function is activated all along the route, it means that the terrain has not to be displayed all thetime. Display of GCAS terrain data on ND (e.g. similar to EGPWS) is out of scope of 3FMS.Upon pilot activation, vertical cut along temporary / active flight plan shall be provided.The display of the 3D situation will be of a great help to display the geographic function.

3.8.2.8.2 Detecting geographic conflicts/incursions

When presenting a conflict with terrain or airspace, it shall be unambiguous. A conflict with terrain, airspaceother than free flight airspace (FFAS), traffic or weather shall always be recognizable.Note : nominally, only conflicts with Airspace should occur.The conflict shall be presented both on ND and VD




Similarly to the traffic and weather case, the CR will calculate the best resolution maneuver.The resolution shall be proposed to the flight crew both on ND and VD.The flight crew shall be informed of the computed resolution. They shall be able to check that:- The solution is compliant with weather and traffic constraints- It is correct with regards to mission parameters (fuel, RTA, …)

3.8.2.8.4 Executing the resolution maneuver

Similar to the traffic separation the CR function shall provide one maneuver. The flight crew shall beprovided the capability to accept/reject/modify the resolution maneuver.

3.8.3 MAS OPERATIONS

SPECIFIC STATION KEEPING REQUIREMENTSThe aim is to acquire and to maintain a separation distance with one other A/C with the same lateral path. Itis assumed here (mainly in order to simplify the MAS function design and improve the robustness ofoperations) that the same lateral path will be EXPLICITLY communicated to both A/C. Thus, a clearancelimited to "follow that A/C" will not be envisaged unless the ATC controller has checked that the aircraftinvolved follow the same lateral flight plan.Both A/Cs do not necessary follow the same vertical path except the ATC altitude clearances.In the slave Aircraft, the flight crew shall be able to manage the activation and deactivation of StationKeeping functions.In both Aircraft, the flight crew shall be able to monitor Station keeping related surveillance parameters. Atleast following information have to be displayed for Master and/or Slave A/Cs:- RNP/ EPE- master A/C position and dedicated information (path, call sign. ..)- route to follow, current separation distance, minimum separation distance, target separation distance,

difference altitude.The flight crew shall be able to manage conflicts (distance out of tolerance) :- detection of conflictresolution of conflict- etc.It is proposed that a new automatic mode to acquire / maintain distance shall be available to the flight crew toalleviate flight crew workload in CLB/DES mode.

4. SYSTEM SAFETY ANALYSISsee the standalone document entitled « Functional Hazard Analysis ».



5. LIST OF FIGURESFIGURE 1 - DEFINITION OF THE SCOPE OF THE FDD ...............................................................................................................2FIGURE 2 - TYPICAL FMS ONBOARD ARCHITECTURE ............................................................................................................5FIGURE 3 - 3FMS OVERVIEW ................................................................................................................................................7FIGURE 4- 3FMS ROLE DEFINITION........................................................................................................................................8FIGURE 5- 3FMS IMPLEMENTATION WITHIN THE NEW FMS.................................................................................................8FIGURE 6- 3FMS DEMONSTRATOR ARCHITECTURE..............................................................................................................10FIGURE 7 - 3FMS FUNCTIONS ARCHITECTURE ................................................................................................................11FIGURE 8-TWG SEPARATION FUNCTIONS ARCHITECTURE...................................................................................................12FIGURE 9-TRAFFIC SITUATION ARCHITECTURE ....................................................................................................................14FIGURE 10- FUNCTIONAL ARCHITECTURE OF THE WEATHER SITUATION FUNCTION ..............................................................17FIGURE 11- GEOGRAPHIC SITUATION ARCHITECTURE ..........................................................................................................21FIGURE 12 - MAS OPERATIONS FUNCTION ..........................................................................................................................26FIGURE 13- SMGCS OVERVIEW ..........................................................................................................................................28FIGURE 14- TAXI MANAGEMENT ARCHITECTURE.................................................................................................................30FIGURE 15 - FM INTERFACE FUNCTION ...............................................................................................................................34FIGURE 16- AIRBORNE AIR-GROUND COMMUNICATION ARCHITECTURE .............................................................................36FIGURE 17- ADS-B SYSTEM ................................................................................................................................................38FIGURE 18- ADS-B SYSTEM ARCHITECTURE .......................................................................................................................38FIGURE 19-AIR-AIR DATALINK FUNCTION...........................................................................................................................40FIGURE 20 -HMI INTERFACE FUNCTION...............................................................................................................................41



6. GLOSSARY OF TERMS3

3FMS: Free-Flight Flight Management System ..................................................................................................................47

A

ACAS: Airborne Collision Avoidance System ...................................................................................................................45ADS-B: Automatic Dependant Surveillance- Broadcast.....................................................................................................39AOC: Airline Operational Center .......................................................................................................................................44ASAS: Airborne Separation Assurance System..................................................................................................................45ATC: Air Traffic Control ....................................................................................................................................................48ATS: Air Traffic Service.....................................................................................................................................................36

C

CI: Cost Index.....................................................................................................................................................................25CLB: CLimB phase.............................................................................................................................................................17COTS: Commercial Of The Shelf .......................................................................................................................................35CPDLC: Controller-pilot DataLink Communication ..........................................................................................................43CR: Conflict Resolution......................................................................................................................................................48CRZ: CRuiZe phase ............................................................................................................................................................17

D

DCDU: Datalink Control and Display Unit ........................................................................................................................43DES: DEScent phase...........................................................................................................................................................17DMD: Data Management and Detection.............................................................................................................................46

E

EGPWS: Enhanced Ground Proximity Warning System....................................................................................................47EPE: Estimated Position Error............................................................................................................................................48ETA: estimated Time of Arrival .........................................................................................................................................44

F

FAA: Federal Aviation Administration.................................................................................................................................4FFAS: Free Flight AirSpace................................................................................................................................................47FIS: Flight Information Service ..........................................................................................................................................18FMP: Flight Management Processing ...................................................................................................................................9FOM: Figure Of Merit ........................................................................................................................................................43

G

GCAS: Ground Collision Avoidance System......................................................................................................................47GNSS: Global Navigation Satellite System ........................................................................................................................38

H

HMI: Human Machine Interface .........................................................................................................................................46

I

ICAO: International Civil Aviation Organisation ...............................................................................................................19IDP: Interface Data Processing .............................................................................................................................................9ISAWARE: Integrated Situation AWAREness.....................................................................................................................7

M

MAS: Managed AirSpace ...................................................................................................................................................48MCDU: Multipurpose Control and Display Unit ................................................................................................................45MORA: Minimum Off Route Altitude ................................................................................................................................20MSA: Minimum Safe Altitude ............................................................................................................................................20



N

NARSIM: NLR’s ATC Research Simulator........................................................................................................................17ND: Navigation Display......................................................................................................................................................48

P

PCI: Passenger Comfort Index............................................................................................................................................25PFD: Primary Flight Display...............................................................................................................................................32

R

RNAV: aRea NAVigation.....................................................................................................................................................4RNP: Required Navigation Performance ............................................................................................................................48RTA: Required Time of Arrival..........................................................................................................................................48RTCA: Radio Technical Committee for Aeronautics .........................................................................................................15

S

SIGMET: SIGnificant METeorological information ..........................................................................................................19SMGCS: Surface Movement Guidance and Control System ..............................................................................................29

T

TCP: Trajectory Change Point............................................................................................................................................39TIS-B: Traffic Information Service-Broadcast ...................................................................................................................15TWG: Traffic Weather Geographic ....................................................................................................................................43

U

UTC: Universal Time Clock ...............................................................................................................................................19

V

VD: Vertical Display ..........................................................................................................................................................48VHF: Very High Frequency..................................................................................................................................................4VOR: VHF Omnidirectional Range ......................................................................................................................................4

W

WGS-84: World Geodetic System -1984............................................................................................................................31



7. 3FMS Terminology

Avoidance - The non-FMS, short term function which produces commands to prevent the aircraft collidingwith terrain or other traffic. Avoidance will be provided by an airborne “safety net” such as GCAS or TCAS.Note that an avoidance algorithm will probably produce only commands and not a fully defined trajectory.

Conflict - The conflict is a predicted loss of separation according to the separation standards defined for theTCAS or EGPWS.

Detection - The FMS process which identifies an obstacle as being a danger to the ownship.

Geographic Data - Includes two categories; Terrain Data & Airspace Restrictions

Intruder - Any aircraft other than the ownship.

Ownship - The subject aircraft, the aircraft which will be simulated by the EPOPEE during the 3FMSdemonstrations.

Resolution - The FMS process which produces a new trajectory which accounts for all detected obstacles. In3FMS this is situated within CR.

Separation - The FMS process by which the aircraft is prevented from conflicting with obstacles (terrain,airspace restrictions, weather or other traffic). Separation consists of two aspects ; detection and resolution.

Strategic - A strategic operation is one which will typically be performed by the FMS (or AOC) beforedeparture and before entry into FFAS.• The strategic planning will occur hours or tens of minutes before any conflicts are detected.• The strategic operation may not have any detailed knowledge of traffic or weather obstacles, but Terrain

orAirspace Restrictions would be taken into account.

• The trajectory computed by the strategic operation is optimized for costs.

Tactical - A tactical operation is one which will be performed by the 3FMS function of the FMS in real-time,in-flight to maintain separation.• The tactical operation will typically occur between 10 min and 30 sec before conflict.• The tactical operation will maintain separation from detected obstacles (Traffic, Weather, Terrain or

Airspace Restrictions) while maintaining the trajectory of lowest cost. (note : In 3FMS terminology, amaneuver computed by any “safety net” functionality is not a tactical operation but an avoidanceoperation. )

Trajectory/Route - These terms are synonymous and interchangeable. A route or trajectory is a 4-dimensional description of the path to be flown by the aircraft. The four dimensions defined are : latitude,longitude, altitude and time.

TWG Functions - (Traffic, Weather & Geographic) These are the functions that detect traffic, weather andGeographic Obstacles.

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