Analysis of Near Mid-Air Collision Reports for the Identification of Locations with High Mid-Air Collision Risk

In the United States alone, there has been an average of 12.4 mid-air collisions of General Aviation (GA) aircraft per year. In order to determine where the risk of a mid-air collision is highest, Aviation Safety Information Analysis And Sharing (ASIAS) reports categorized as near mid-air collisions were visualized. Two databases in the ASIAS system were of interest: ASRS and NMACS. The databases were searched for every event classified as a near mid-air collision from 2000 to 2010. The results of the visualization show that the airport environment is the location where most near mid-air collisions occurred (ASRS 64% and NMACS 47%). Also, the data indicates that the encounters between commercial (Part 121) aircraft and general aviation (GA) aircraft are most likely when the GA aircraft is in cruise and the commercial aircraft is in any other flight phase, specifically climbing or descending. This is likely due to commercial aircraft often transitioning through altitude layers where GA aircraft would be cruising. A distinct grouping can be observed in the altitudes at which the these GA/Commercial aircraft encounters occur: 2000 ft above ground level and 10,000 feet above ground level.  The detailed summary (attached file) evaluates the implications of those observations.