What happens when a small drone hits a person on the ground? Not much. That’s the conclusion of research from the Alliance for System Safety of UAS through Research Excellence (Assure). The 18-month study was conducted by researchers from the University of Alabama in Huntsville, Mississippi State University, the National Institute for Aviation Research (NIAR) at Wichita State University, and the Ohio State University. 

More than 512 impact tests and simulations were conducted using 16 different multi-rotor and fixed-wing sUAS, as well as various objects and payloads (batteries, wood blocks, etc.) with weights ranging from 0.71 to 13.2 pounds. Testing also included evaluation of heavier sUAS using mitigations to reduce potential for injury, such as sUAS under parachutes. 

“Injury impacts conducted in the study were controlled impact tests of the worst case, using those variables capable of transferring the most energy to a human,” said principal researcher David Arterburn of the University of Alabama at Huntsville. “Even in these controlled studies, slight variations of the vehicle orientation or location of impact with the human, just prior to impact, reduced the injury potential. These results showed that these worst-case impacts are very difficult to achieve, even under controlled impact test conditions.”

The research team conducted fixed-wing and multi-rotor sUAS failure flight testing and aerodynamic modeling, full anthropomorphic test device (ATD) impact testing, simplified head and neck only ATD impact testing, Post Mortem Human Surrogate (PMHS) impact testing, ATD and human-body model impact simulations, and high-fidelity head and neck only impact simulations. 

“The research results give the FAA a better picture of potential injuries and their severity, based on established science,” said Assure executive director Stephen Luxion. “Earlier testing of injury data strongly supported our assessment that long-standing fatality data was overly conservative and largely not applicable to injuries resulting from impacts by more elastic sUAS. Additional testing was needed to develop a more accurate, science-based test methodology that may be used by the FAA, sUAS manufacturers, and operators of sUAS to evaluate the injury risk potential.”

According to Assure, the research findings and data might help inform the FAA and industry of operational limitations for sUAS when operating over people and used to develop design specifications to further reduce risk to people and property on the ground.