Marisa Garcia The FAA and the Alliance for System Safety of UAS through Research Excellence (ASSURE) studied what would happen if a drone hit a person on the ground.
Research into this question began in September of 2015 conducted by the ASSURE research team, which led by The University of Alabama in Huntsville in collaboration with the University of Kansas, Mississippi State University and Embry-Riddle Aeronautical University.
The results of their studies are intended to help the FAA shape future research and ultimately set guidelines for UAS (more commonly known as drones) flying over areas where people may gather which could influence the design specifications of drones in future to reduce risks to people and property.
“The results of this work are critical to the successful commercial operations of flying unmanned aircraft over people and beyond the pilot’s visual line of sight,” said Mississippi State University’s Marty Rogers, director of ASSURE.
To evaluate risks, the group conducted crash tests, dynamic modelling and analyses of kinetic energy, energy transfer, and crash dynamics.
The FAA and ASSURE members published their findings at the FAA Federal Headquarters in Washington, DC on Friday the 28th of April, in a report entitled The UAS Ground Collision Severity Evaluation Final Report.
Identified are three dominant types of injuries which can be caused by small drones falling from the sky overhead.
- Blunt force trauma – the most significant contributor to fatalities
- Lacerations – blade guards required for flight over people
- Penetration injuries – difficult to apply consistently as a standard
“The research team reviewed over 300 publications from the automotive industry, consumer battery market, toy standards and other fields to inform their research using the most modern research techniques,” said David Arterburn, director of the Rotorcraft Systems Engineering and Stimulation Center at the University of Alabama in Huntsville and principal investigator for the study. “From these, we were able to identify blunt force trauma, penetration injuries and lacerations as the most significant threats to people on the ground.”
Other hazards may be caused by drone components, including unprotected rotor blades, for which the group recommends rotor blade guards as a protective measure “to reduce the severity of injury.”
Not all drones fall alike
Research by the FAA and ASSURE found that the aerodynamic drag of multi-rotor drones may cause these to fall more slowly and cause less damage than a block of metal or wood of the same mass falling overhead. “Drones also deform and flex more than wood and metal debris, imparting lesser amounts of energy and, therefore, less damage,” the FAA states in its announcement. However, the FAA calls special attention to the need for safety standards for the lithium batteries that power these aerial vehicles.
A second phase of ASSURE’s research into drone hazards is scheduled to begin in June of this year. It will verify the findings of the initial study and develop tests that drone manufacturers can use to certify their drones for flights over people.
