Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-1A The Transition Towards Free Flight: A Human Factors Evaluation of Mixed Equipage, Integrated Air-Ground, Free Flight ATM Scenarios World Aviation Congress 1999, 99WAC-111 San Francisco, 19 October 1999 R.C.J. Ruigrok, R.N.H.W. van Gent, J.M. Hoekstra

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-2A Explanation of title l The Transition Towards Free Flight: –in time and in space l A Human Factors Evaluation –objective and subjective measurements l of Mixed Equipage –aircraft with and without ADS-B, CDTI and CD&R l Integrated Air-Ground –air and ground players have a defined role l Free Flight ATM Scenarios –newly defined

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-3A Overview l NLR studies on Free Flight l 1997 human-in-the-loop experiment –in summary l 1998 human-in-the-loop experiment –in detail l Conclusions and recommendations

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-4A NLR studies on Free Flight Overview l Studies on Airborne Separation Assurance, the flight deck perspective: –Conceptual design and off-line validation –Safety analysis –1997 human-in-the-loop experiment –Cost/benefit analysis –Avionics requirements study –Critical conflict geometry study –1998 human-in-the-loop experiment l In collaboration with NASA, FAA and RLD In summary In detail

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-5A 1997 human-in-the-loop experiment Method l Probe the limits –No Air Traffic Control –Air crew responsible for traffic separation l All aircraft in scenario fully equipped –Automatic Dependent Surveillance - Broadcast (ADS-B) –Conflict Detection & Resolution (CD&R) –Cockpit Display of Traffic Information (CDTI) l Cruise flight only –Direct routing –Optimal cruise altitude

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-6A 1997 human-in-the-loop experiment Scenarios l Traffic Densities: –Single –Double –Triple l Level of Automation: –Manual –Execute Combined –Execute Separate l Non-Nominal: –Other aircraft failures/events –Own aircraft failures/events –Delay time increased

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-7A 1997 human-in-the-loop experiment Results l Acceptability: –91.5% (single), 83.0% (double), 78.7% (triple) l Safety: –88.3% (single), 75.5% (double), 71.3% (triple) l Workload: –ratings less than 40, indicating “costing some effort” l Across all densities, across all sessions, across all subject pilots, including non-nominal events

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-8A Conclusion: The feasibility of Free Flight with Airborne Separation Assurance could not be refuted 1997 human-in-the-loop experiment Conclusion and Issues raised l Issues raised: –Prevent short term intrusions of protected zones due to sudden maneuvers of proximate aircraft –Transition to Free Flight (Airspace) –Mixed equipped traffic scenarios

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-9A 1998 human-in-the-loop experiment Research questions to answer l How to accommodate mixed equipage in a transitional free flight era ? l What will a future ATM system containing Free Flight elements look like ? l Will there be a clear distinction between Managed Airspace (MAS) and Free Flight Airspace (FFAS) or can it be mixed ? l What is the role and responsibility of the ground controller and pilot ?

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-10A 1998 human-in-the-loop experiment Method l Improved ASAS equipment: –to prevent sudden maneuvers of nearby aircraft l Three newly developed ATM operational scenarios: –to study the transition to Free Flight Airspace (in space) l Two levels of equipage and traffic density: –to study the transition towards Free Flight in time l The experiment contained an air (flightdeck) and ground side (ATC) which shared traffic scenarios

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-11A 1998 human-in-the-loop experiment ASAS equipment l The Airborne Separation Assurance System (ASAS): –Automatic Dependent Surveillance - Broadcast (ADS-B), Traffic Information Service - Broadcast (TIS-B) –Conflict Detection and Resolution (CD&R) –Cockpit Display of Traffic Information (CDTI) –Predictive ASAS (PASAS) –Alerting logic

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-12A ASAS equipment Conflict Detection & Resolution ownship intruder minimum distance protected zone intruder avoidance vector advised vector 1. heading change 2. speed change not shown: 3. vertical speed change

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-13A ASAS equipment Cockpit Display of Traffic Information l Navigation Display –Traffic Symbology –Conflict Detection –Resolution Advisories –Vertical Navigation Display –Extra EFIS Control Panel functionality

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-14A ASAS equipment Predictive ASAS l “no-go” bands for – track/heading – vertical speed – speed

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-15A 1998 human-in-the-loop experiment ATM Scenarios l Starting points: –equipping aircraft should be immediately beneficial to the airlines –equipping should be economy driven instead of mandatory –benefit the equipped aircraft, without excluding the unequipped aircraft l Three ATM operational scenarios with Free Flight elements defined, implemented and tested: –Flight Level –Protected Airways –Full Mix

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-16A 1998 human-in-the-loop experiment ATM Scenarios: Flight Level l Airspace above a certain altitude (the “Lower Free Flight level”, FL260) is reserved for equipped aircraft only l Transition layer used as a buffer zone for aircraft transitioning to and from Free Flight l Flying high is beneficial

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-17A 1998 human-in-the-loop experiment ATM Scenarios: Protected Airways l The airspace structure remains intact l Unequipped aircraft are ground controlled and have to stay on airways l Equipped aircraft have the right to leave the airways for direct shortcuts l Direct routing is beneficial

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-18A 1998 human-in-the-loop experiment ATM Scenarios: Full Mix l All aircraft fly direct, free routing l Unequipped aircraft are ground controlled (ATC) l ATC performs conflict resolution for unequipped aircraft using a longer look-ahead time for conflict probing l Unequipped aircraft will always avoid equipped aircraft, beneficial for the equipped aircraft

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-19A 1998 human-in-the-loop experiment Experimental design l Experiment matrix: –Traffic Density - low density versus high density –Equipage - 25% versus 75% ASAS equipped –ATM operational concept - Flight Level, Protected Airways and Full Mix l The high traffic density, Flight Level ATM condition was excluded l 8 pilot subjects

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-20A 1998 human-in-the-loop experiment Results: Acceptability l Scale: –Perfect in every way = 5 –Favourable = 4 –Acceptable = 3 –Unacceptable = 2 –Completely unacceptable = 1

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-21A 1998 human-in-the-loop experiment Results: Safety l Scale: –FF much safer = 5 –FF safer = 4 –same as ATC = 3 –ATC safer = 2 –ATC much safer = 1

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-22A 1998 human-in-the-loop experiment Results: Workload l Subjective by means of questionnaires with Rating Scale of mental Effort (RSME) l Objective by means of Eye- Point-Of-Gaze measurements l Scan randomness (entropy) used as objective metric for Workload

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-23A 1998 human-in-the-loop experiment Results: Workload Subjective:Objective:

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-24A 1998 human-in-the-loop experiment Conclusions l The future ATM design has to be chosen very carefully: –Full Mixed ATM condition is best from the pilot’s perspective –Protected Airways ATM condition is sensitive to equipage level (transition in time) –Flight Level ATC condition is most optimal from Air Traffic Controller’s perspective (Hilburn, Pekela) l The flightdeck crew was able to handle higher traffic densities than the ground controller

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-25A 1998 human-in-the-loop experiment Future plans l Verify all assumptions: –“multi-pilot and multi-controller in the loop” experiment is planned using Internet gaming facilities –ADS-B characteristics –Flight testing using “real” data l Study the integration of traffic, weather and terrain information in the cockpit

Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR DXXX-26A Contact / More information hosted-sites/freeflight