1. Work Domain Analysis of TCAS Interface Design Danny Ho and Catherine M.Burns Advanced Interface Design Lab Department of Systems Design Engineering University of Waterloo Research Summary This poster discusses the progress of Work Domain Analysis(WDA) applied to the Traffic Alerts and Collision Avoidance System(TCAS)in the aircraft cockpit.The goal is to investigate automation effects on TCAS-pilot interaction,and to develop and test new interfaces that may improve the performance of mid-air collision detection and avoidance without increasing pilot workload.Challenges include the creation of accurate framework representation that models collision detection and avoidance, and applying Ecological Interface Design(EID)to develop appropriate status and command interface components.Prototyped displays will be user tested and evaluated to measure automation effects on TCAS performance.Potential results from this research will help reduce midair collision incidents. TCAS Symbology Non-Threat Traffic An open white diamond indicates that an intruder’s relative altitude is greater than plus or minus 1200 feet vertically or its distance is beyond 6 nm range. It is not yet considered a threat. Thisone is 1700 feet below your own altitude, climbing at 500 feet per minute or greater. Traffic Advisory (TA) A symbol change to a filled yellow circle indicates that the intruding aircraft is considered to be potentially hazardous. Depending on your altitude TCAS II will display a TA when the time to CPA is between 20 and 48 seconds. A voice announcement is heard in the cockpit, advising,“Traffic, Traffic” Proximity Traffic A filled white diamond indicates that the intruding aircraft is within plus or minus 1200 feet vertically and within 6 nm range, but is still not considered a threat. This intruder is now 1000 feet below your aircraft and climbing. Resolution Advisory (RA) A solid red square indicates that the intruding aircraft is projected to be a collision threat. The time to closest approach with the intruder is now between 15 and 35 seconds depending on your altitude. A synthesized voice announces a vertical maneuver command, such as, “Climb, Climb, Climb.” Automated Message and Response Current TCAS II System Standard System for TCAS Symbols Leveson N.et al,"Sample TCAS Intent Specification",Safeware Engineering Corp.Leveson N.et al,"Sample TCAS Intent Specification",Safeware Engineering Corp. Abstraction Hierarchy TCAS II Functional GoalsTCAS II System Components 1)Leveson N.et al,"Sample TCAS Intent Specification",Safeware Engineering Corp. 2)Collision Avoidance System User’s Manual TCAS II/ACAS II,ACS-5059, Rev5-02/2000,Honeywell Inc. References Moradi-Nadimian et al,Ecological Interface Design in Aviation Systems, 'http://sydewww.uwaterloo.ca/Research/AIDL/new/v1/Projects/Aviation/index.htm',2002. Ongoing Research Direction Work domain analysis(WDA)is being conducted with the focus on goals in the context of collision detection and avoidance only. The accumulative automation effects of air traffic control,intruder ship systems,and ownship TCAS is being further explored to develop interface designs to improve performance of the TCAS system.