From 2014 to 2018 the FAA recorded 6,117 reports of near encounters between manned and unmanned aircraft within the National Air Space.
Such close encounters are bound to increase, given the number of unregulated small unmanned aerial systems (sUAS) in the air, according to the researchers.
The FAA has projected that the small model hobbyist UAS fleet in the United States will “more than double from an estimated 1.1 million vehicles in 2017 to 2.4 million unmanned aircraft by 2022,” and “the number of remote pilots is set to increase from 73,673 in 2017 to over 300,000” in the next four years.
The Embry-Riddle Aeronautical University study was conducted near Daytona Beach International Airport (DAB) in Florida. The research team installed and gathered data with a DJI AeroScope, a UAS detection platform that rapidly identifies unmanned aircraft communication links and gathers flight status, paths, and other information in real-time, the researchers explained.
During the 13-day sampling period, researchers detected 73 individual DJI-manufactured drones that made 192 separate flights in the Class C airspace around the airport.
The study looked at drones from only one manufacturer, so there were most likely many more flights of sUAS near the airport over the 13 days that were not cataloged, the researchers noted.
Researchers also collected operator behavior data, including common sUAS flight locations, times, and altitudes.
Operational data was compared against published FAA UAS Facility Maps to examine potential risk areas.
The researchers said they were surprised that only 12% of these small unmanned aircraft were flying near unimproved land and parks.
More than three-fourths were flying in residential neighborhoods or near single-family homes.
Another 21.5% hovered above commercial, industrial or public properties, the researchers reported.
“This was an unexpected finding,” said Assistant Professor of Aeronautical Science Dr. Ryan Wallace, lead author of the study. “We thought most drone operators would choose relatively open areas offering a safety buffer from hazards, but that wasn’t the case.”
The researchers compared detected sUAS activity with locations and altitudes prescribed by the FAA’s UAS Facility Maps.
According to the FAA, “UAS Facility Maps show the maximum altitudes around airports where the FAA may authorize Part 107 operations without additional safety analysis.”
More than 20% of the 177 flights were flying higher than the safe altitude prescribed for their operating area, the study discovered.
Researchers also compared detected UAS operations to historical manned aircraft flight data, revealing several near encounters.
“These data suggest that more than one in five sUAS flights presented an unmitigated risk to nearby manned aviation operations,” the researchers concluded.
The researchers suggest that drone manufacturers should more frequently incorporate a technology called “geofencing,” which would prevent sUAS from accidentally entering restricted areas.
Geofencing is a virtual barrier using a GPS network and Local Radio Frequency Identifier (LRFID) connections such as Wi-Fi or Bluetooth beacons. This boundary is determined by a combination of hardware — the unmanned aircraft — and software — a drone app — that dictates the parameters of the geofence. Unfortunately, not all drones are using this technology, the researchers reported.
The study’s authors also propose that the FAA could consider making more information on sUAS activity available to aircraft pilots.
The study, “Evaluating Small UAS Near Midair Collision Risk Using AeroScope and ADS-B,” was published by the International Journal of Aviation, Aeronautics and Aerospace.