Ecological Interface Design in Aviation Domains:

Improving Pilot Trust in Automated Collision Detection and Avoidance

Danny Ho

Dr. Catherine M. Burns

Advanced Interface Design Lab

Systems Design Engineering

University of Waterloo

Establishing Perspective

On July 1, 2002:

Bakshirian Airlines Tupolov 154 collided with a DHL Cargo Boeing 757-200 over Southern Germany

Sequence of events as the two aircraft converged:

1) Onboard collision system told Boeing to climb

2) Onboard collision system told Tupolov to descend

3) Air traffic control (ATC) told Tupolov to climb

4) Boeing climbed

5) Tupolov climbed

6) Collision occurred at 35,000 feet. There were no survivors.

The system FAILED! How?

Outline

Problem and ObjectiveMethodology

Ecological Interface Design (EID) Work Domain Analysis (WDA)

Current System of Focus Traffic Alerts and Collision Avoidance System (TCAS)

Applying EID to Collision Systems Implementation EID-Enhanced Displays

Experimental Approach & DesignFuture Direction & Conclusions

Exploring The Problem

Possible Contributing Factors Policies and procedures

North American versus European policy Human Factors

Pilot execution Cognitive performance Interface inadequacies Trust in automation

The Problem of Interface

The pilot may not have the necessary information to perform effectively in the automated alerting situation

The pilot didn’t know who to trust TCAS or ATC?

Defining The Objective

To propose display enhancements and evaluate their effects on pilot trust and decision making performance in automated air traffic alerting conditions

It is hypothesized that: An EID-enhanced display will increase decision making

performance and accuracy An EID-enhanced display will increase pilot trust in

automated air traffic alerting systems

The Methodology

Ecological Interface Design (EID)

A framework for designing interfaces primarily for complex systems (Vicente, Rasmussen, 1992)

Nuclear power plant control (Rasmussen, 1985) Aircraft engineering system (Dinadis & Vicente, 1999) Shipboard command and control (Burns et al., 2000)

Shown to improve operator task performance and conflict detection because it develops a contextual information link to the trained operator

Draws from Work Domain Analysis (Rasmussen 1985) as a design basis

The Methodology

Work Domain Analysis (WDA) Abstraction Hierarchy (AH): A 5-layered systems

approach to component and interaction representation

WHY?

HOW?

The Methodology

EID: “What data should be extracted, and how should it be represented to help the user understand the system?”

UCD: “How do users perform, and what interface elements can be used to optimize their task performance?”

The EID methodology may produce displays that convince pilots to perform a task rather than command them to perform a task

The System - TCAS

Traffic Alerts and Collision Avoidance System TCAS 2 – version 7.0

Internationally adopted and mandated by FAA for all North American aircraft with capacity exceeding 30

Operates independently of onboard systems/radar

TCAS 1 introduced in 1981 TCAS 1 provides only collision detection TCAS 2 also calculates and proposes avoidance maneuvers

Not a ‘leading-edge’ system, but the most proven system

Design methodology can be applied to other systems as well

2 Levels of Alerts- TA : Traffic Advisory

- ‘traffic, traffic’- RA : Resolution Advisories

- ‘climb’, ‘descend’, etc…

Data Inputs- intruder range, altitude, bearing

- ownship range, altitude, bearing

Operational Parameters- protected volume varies with speed

- threat based on time, not distance

- pilot must inform ATC of RA maneuver

- pilot must return to ATC course after RA

- no RA’s under 1000 ft altitude

- system accounts for slow convergences

- if intruder doesn’t react to their RA, ownship RA can be recalculated

TCAS Overview

TCAS for MS Flight Sim 2002

Collision Avoidance Example

Applying EID to Collision Systems

This study introduces a novel approach to applying EID to collision detection and avoidance, dividing the problem into 3 entities to extract informational requirements

(A)ircraft, (C)ollision System, and (E)nvironment A: One AH representing flight dynamics for each aircraft

involved in the encounter C: One AH of the TCAS system for each aircraft E: One AH describes the airspace of the collision

encounter

Aircraft – Flight Dynamics

Ailerons

Collision System - TCAS

Collision Environment

The Entities Interact!

TCAS can be switched out and another system(e.g. ADS-B) can be evaluated in its place

Iterate through the informational requirements stage to develop a solution that meets your specific design challenges

EID-Enhanced TCAS Displays

D1: unmodified TCAS symbology

D2: circle around aircraft indicates protected volumes, red circle represents predicted collision area, time to loss of separation (LOS) is also indicated in seconds

D3: TIME to LOS is used as radar scale instead of separation distance, LOS time shown, and ground speed velocity indicators for each aircraft

Experimental Design

Within subjects designRandomized display conditions: D1, D2, D3

repeated measures ANOVADependent variables

Reaction time after alert until intent to maneuver Conformance to TCAS calculated maneuver

Questionnaires of self-confidence and trust

Future Direction and Conclusions

Experimental results will indicate if EID-enhanced displays improve pilot reaction time and conformance to TCAS alerts

Results comparison between D2 and D3 will provide additional information on the effects of distance-scaled versus time-scaled displays on collision detection performance

Qualitative interpretation shall illustrate the influence of EID-enhanced displays on pilot trust in automated displays

EID Summary

The EID framework is very flexible in its application

In this study, EID highlights aircraft flight dynamics and the threat environment in which a collision occurs, all of which interact with components of the automated warning system.

Although the system of focus is TCAS, the flexibility of EID and WDA allows this model to be adapted to any automated collision warning system being developed for aviation. The TCAS entity can be replaced with ADS-B and other systems to produce new system interactions and information requirements for exploring EID-enhancements

References

Burns, C.M., Bryant, D.J., & Chalmers, B.A. (2000). A work domain model to support shipboard command and control. Proceedings of IEEE Transactions on Systems, Man and Cybernetics. 2228 – 2233.

Dinadis N., & Vicente, K.J. (1999). Designing functional visualizations for aircraft systems status displays. International Journal of Aviation Psychology. Vol. 9 (3), 241-269.

FAA (2000). Introduction to TCAS II Version 7. U.S. Dept. of Transport. Federal Aviation Administration. Nov. 2000.

Rasmussen, J. (1985). The role of hierarchical knowledge representation in decision-making and system management. IEEE Transactions on Systems, Man and Cybernetics, 15(2), 234-243.

Vicente, K.J. & Rasmussen, J. (1992). Ecological interface design: Theoretical foundations. IEEE Transactions on Systems, Man and Cybernetics, 22(4): 589-606

Acknowledgements

Centre for Research in Earth & Space Technology (CRESTech) Sion Jennings, NRC Flight Research Lab Dr. Catherine M. Burns Members of AIDL Microsoft, software and hardware sponsor Jin Qian, Dr. Jeanette O'Hara-Hines

Department of Statistics & Actuarial Sciences, U of Waterloo SYDE, GSO & GSEF for conference funding Thesis readers:

Dr. Carolyn MacGregor, SYDE, UW Dr. Hamid Tizhoosh, SYDE, UW

Thank you!

For more info: ycdho@uwaterloo.ca http://thinair.uwaterloo.ca/~ycdho/aidl.html

Microsoft Flight Simulator 2002 TCAS download!

Display / Expmt. References Alexander, A.L., Wickens, C.D., (2001). Cockpit display of traffic information: the effects of traffic

load, dimensionality, and vertical profile orientation. Proceedings of the Human Factors and Ergonomics Society 45th Annual Meeting, 105-109.

Barhydt, R. and Hansman, R.J., (1999). Experimental studies of intent information on cockpit traffic displays. Journal of Guidance, Control, and Dynamics, Vol. 22, No. 4, AIAA, July-Aug. 1999, 520-527.

FAA (2000). Introduction to TCAS II Version 7. U.S. Dept. of Transport. Federal Aviation Administration. Nov. 2000.

Galster, S.M., Bolia, R.S. (2001). Effects of Automated cueing on decision Implementation in a Visual Search Task. Proceedings of the Human Factors and Ergonomics Society 45th Annual Meeting, 321-325.

Krishnan, K., Kertesz, S.Jr., Wise, J.A., (2000). Putting four dimensions in “perspective” for the pilot. Proceedings of the IEA 2000/HFES 2000 Congress, 3-81 - 3-84.

Pritchett, A.R., Vándor, B., (2001). Designing situation displays to promote conformance to automatic alerts. Proceedings of the Human Factors and Ergonomics Society 45th Annual Meeting. 311 – 315.

Rovira, E., McGarry, K., Parasuraman, R. (2002). Effects of unreliable automation on decision making in command and control. Proceedings of the Human Factors and Ergonomics Society 46th Annual Meeting, 428-432.

Other Traffic Display Studies

Consonance and dissonance studies related to automatic alerts

(Pritchett & Vandor, 2001)

Look ahead prediction envelopes such as T2CAS (Fulgham, 2003)

‘Future cone’ analogies (Krishnan, Kertesz, & Wise, 2000)

Geometric predictor symbology (Gempler & Wickens, 1998)

Traffic intent information in TCAS (Barhydt & Hansman, 1997)

TCAS Aural and Visual Alerts (incomplete)

TCAS FL Alerting Thresholds

Experimental Design

Participant background questionnaireTCAS, MSFS tutorialTCAS calculation proficiency exercise3 sets of display condition trials (randomized)

Subjects press a button to show intent to maneuver 5 trials with colliding traffic, TCAS alerting on 8 trials with TCAS on/off, colliding/non-colliding traffic

evenly permutated scenarios (randomized order) NASA-TLX, self-confidence, and trust level surveys

Overall display preference questionnaire