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The roles and responsibilities of air traffic controllers and pilots are shifting in the advent of the NextGen air traffic management infrastructure, which also involves high levels of automation. It is important to understand just how large departures from the current ingrained practices the NextGen procedures represent, particularly in extremely safetycritical tasks such as airborne conflict resolutions. Pilots’ conflict resolution maneuver preferences have received some attention, but corresponding research on air traffic controllers’ practices is almost nonexistent. We analyzed 87 samples of aircraft track data involving conflict alerts and subsequent resolution maneuvers from Atlanta center. Vertical conflict resolution maneuvers were used in the majority of the cases examined. Within the vertical dimension, reductions of current vertical change (climb or descent) were collectively the most frequent resolution maneuver type, but descents were twice as frequent as climbs. Conflict resolution maneuvers furthermore do not seem to be independent from conflict geometries.