Human Factors Evaluation of Conflict Resolution Advisories

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Authors: Sonia Alvidrez
Robert Bastholm
John DiRico
Sehchang Hah, PhD.
Kevin Hallman
Joshua Harrison
Daniel R. Johnson
Karl A. Meyer
Gary Mueller
Jonathan Rein, PhD.
Kenneth Schulz
Scott Terrace
Ben Willems
Hyun Woo

Hah, S., Willems, B., Mueller G., et al. (2013). Human Factors Evaluation of Conflict Resolution Advisories in the En Route Domain (DOT/FAA/TC-13/55). Atlantic City International Airport, NJ: Federal Aviation Administration William J. Hughes Technical Center.


Objective: In this human-in-the-loop simulation experiment, we evaluated how Conflict Resolution Advisories (CRA) affected en route controllers.

Background: Controllers currently use a conflict probe and trial planning tool, known as the User Request Evaluation Tool (URET), which is available on the Radar Associate Position. However, under Trajectory-Based Operations—that is, Separation Management Modern Procedures (SepMan)—several capabilities will become available to the Radar Position, including probed menus, conflict detection and trial planning, and support for multiple separation minima within a sector‘s airspace. The CRA Program is built upon the SepMan concept and will provide a proposed solution to a potential conflict as soon as a controller initiates the entry of a clearance.

Method: Twelve current en route Certified Professional Controllers from Air Route Traffic Control Centers participated in the experiment.

Results: CRA capabilities did not change controller workload nor time and distance flown by aircraft in the sector. Analysis of tactical and strategic conflict alerts show that controllers solved potential conflicts quickly when CRA was available. Most of the participants‘ subjective ratings favored the CRA, and participants expressed that CRA was a useful concept.

Conclusion: The results show an advantage of CRA on some air traffic control tasks. In general, CRA was accepted by the participant controllers.

Applications: With a few modifications of the current CRA features and functions, the authors believe that CRA will be a useful automation tool for air traffic controllers.