Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-1A Designing for Safety: the Free Flight ATM concept Jacco Hoekstra Ronald van Gent Rob Ruigrok

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-2A 1997: Three sub-studies: l CONCEPTUAL DESIGN Tool: Traffic Manager: Off-line simulations –Find a suitable base-line concept l SAFETY ANALYSIS Tool: TOPAZ (Traffic Organization and Perturbation AnalyZer) –Compare safety of Airborne Separation with safety ATC l MAN-IN-THE-LOOP EXPERIMENT Tool: Research Flight Simulator –Validation of concept with Man-in-the-Loop –Man Machine Interface Validation

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-3A Free Flight goals l Reduce Costs via user preferred routing –Horizontally direct to destination optimum speed –Vertically optimum level cruise climb l More capacity

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-4A Starting points l No ATC –Probe the limits for HF problems l All aircraft fully equipped –Linked via e.g. ADS-B –EFIS-CDTI l Full user preferred routing –Direct routing –Optimal cruise altitude

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-5A Traffic & Experiment Manager TMX

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-6A l Resolution advisories Several concepts studied: –Altitude step –Cross product of speed vectors –Extended VFR rules (not implemented) –Variations of TCAS manoeuvres –Voltage potential l Co-operative manoeuvring vs. priority l Minimal bandwidth/HF: no intent in Conflict Detection Conceptual Design

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-7A Conflict Detection & Resolution Intruder’s protected zone Heading distance Speed change Avoidance vector Minimum distance Ownship Intruder

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-8A Airborne Separation subtasks l Monitoring traffic situation on display l Conflict detection l Conflict resolution l Inter-traffic R/T

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-9A Monitoring traffic situation on display l Symbology on Navigation display based on data available via ADS-B l Track indicated with arrow shaped symbol instead of track line to avoid clutter l Label text selectable with declutter switches

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-10A Conflict Detection & Resolution l Symbology based on resolution algorithm l Provides insight into resolution l Colour indicates urgency: Amber = min Red = min (time to loss of separation)

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-11A Inter Traffic R/T l Call sign added to label of traffic symbol

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-12A Navigation Display

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-13A Topaz Safety Analysis l Two airways in opposite direction l Independent variables: route spacing, non-nominals l Dependent: Collision frequency l ASAS equipped, airborne separation, good weather, no global ADS-B failure, independent transmitter & receiver l No monitoring modelled on ground & air Airway Route spacing

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-14A TOPAZ : Ground vs. Airborne Separation

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-15A TOPAZ : Airborne Separation

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-16A Man-in-the-Loop experiment Hypotheses First explorative HF experiment, so probably: l Less than acceptable l Subjectively less safe l More workload Goal: MMI problem areas

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-17A Man Machine Interface l Modifications to Navigation Display –Traffic symbology –Conflict detection –Resolution Advisories –Vertical Navigation Display –Extra EFIS Control Panel functionality l Modifications to Autopilot –Execute combined –Execute separate l Aural alerts l Dedicated blue light under glareshield

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-18A Man-in-the-loop simulation

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-19A Experimental Design Place of non-nominals in matrix changed between subject crews 18 runs per crew air line pilots 2 days incl. half a day of training

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-20A Man-in-the-loop Simulation Configuration AIRSIM RFS TMX

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-21A Man-in-the-Loop experiment Results - Acceptability

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-22A Man-in-the-Loop experiment Results- Subjective Safety

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-23A Man-in-the-Loop experiment Results

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-24A Task comparison Controlled vs. Free Flight

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-25A Conclusions 1997 l Free Flight concept as implemented is acceptable in cruise phase, even in higher than WE densities l Workload in a future Free Flight scenario in cruise phase is not higher than in present day ATC scenario l Free Flight concept is at least as safe as present day ATC l None of the three sub-studies (off-line simulations, TOPAZ safety analysis, Man-in-the-Loop experiment) could refute the feasibility of an Airborne Separation Assurance concept for a future Free Flight environment.

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-26A Recommendations l Fine tuning of conflict detection & resolution based on remarks of pilots l Intended Flight Level in label? l Extra rule to prevent turning into short-term conflicts: =>Predictive ASAS

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-27A 1998 Student studies l Avionics requirements - navigation - ADS-B (bandwidth) - reliability => today’s technology +ADS-B allows FF l Conflict geometries (TMX) - Wall scenario - Super conflicts - Shallow conflicts (hor. + vert.) => tuning of CD&R l Performance and fuel/time aspects of conflict resolution - simulations Fokker 100 on TMX => Vertical optimal, FF savings due direct routing high

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-28A 1998 Man-in-the-loop study l Mixed equipage procedures - Free Flight Level (ASAS flies higher) - Protected airways (non-ASAS stay on airways) - Fully mixed (non-ASAS longer look-ahead time) l Predictive ASAS - system developed on TMX - enhances situational awareness - new rule: it is forbidden to turn into a short-term conflict l Pilots & controller in the loop - only in single and double density connected (triple too high for ATC)

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-29A Mixed equipage procedures l Data analysis is in progress l Preliminary results (impressions): - protected airways not feasible - FF able to cope with higher traffic density - co-operative/corrective action from airborne crew

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-30A Predictive ASAS Calculates which track, vertical speed and speed selections will result in a conflict within the look ahead time Predicts a conflict by the red/amber zone moving to the actual values Indications do not require pilot actions

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-31A Predictive ASAS Don’t go indications: Track Vertical speed Speed

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-32A Preliminary conclusions PASAS l With predictive ASAS even conflict alerts could be avoided l Enhances situational awareness l Might provide solution without use of intent information for Free Flight!

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-33A Plans for 1999 l Further data analysis of 1998 experiment l Comprehensive report on overall studies l Human interaction experiment (?)

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-34A Distributed vs. Centrally controlled systems l Chaos l Robustness l Capacity l Safety and certification l Challenging for analysis

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-35A Conclusion l Free Flight promises to be very powerful: - fuel & time savings - higher capacity - safer (more robust, also technology dep.) - no reliance on ground aids and their reliability - individual self-optimisation l Needs further research!!! l FF will happen: now or in the future… No change is also a risk!

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR CXXX-36A NLR Free Flight Web site or via NLR home page and select hosted sites