FAA Releases Drone Risk Report
“A start toward better understanding the risks of allowing small unmanned aircraft — or drones — to fly over people”
In late April the FAA released the final ‘ASSURE UAS Ground Collision Severity Evaluation Report‘. The 195-page drone risk report details drone crash testing along with digital models of the damage falling drones can cause. Also included is data on and analysis of a broad range of consumer and commercial systems, all under 55 pounds. The report does not address the probability of a system failure or other causes.
This is the first product of many to come from collaborative research seeking to understand and quantify the real risks of drones flying over people.
This report is the first public product of the FAA’s Alliance for System Safety of UAS through Research Excellence (ASSURE). According to AOPA, the report reads like old-fashioned common sense backed up by computational fluid dynamics:
“The kinetic energy for the worst case terminal velocity or maximum cruise airspeed, energy density, and rotor diameter are the most significant UAS characteristics contributing to blunt force trauma penetration and laceration injuries, respectively,” the report states.
Meaning, the bigger the drone, the harder it falls, and the faster it flies, the more likely it is to cause injury or death in a collision. To read the full report please click here.
The Research & Testing
The research effort includes 23 academic institutions working alongside with the FAA. Key participants were Embry-Riddle, Mississippi State University, the University of Alabama in Huntsville, University of Kansas, and Wichita State University. Together the teams sought to answer was, when a drone fails and falls into a crowd, what, exactly, happens next?
The testing involved flinging a Phantom 3 drone into crash test dummies. Lacerations and punctures, from the propellers, are among the principal risks. A falling Phantom would have a probability of causing neck injury ranging from 11 to 13%.
The researchers made a case that propeller guards on multi-rotor aircraft are “critical” to safe operations over people. They not only limit the damage done by spinning blades but also create enough drag to make a difference.
“There is a 42% increase in the vertical flat plate drag area, and a 19.6% increase in the lateral flat plate drag area when the guards were added to the vehicle configuration,” the researchers wrote. “Not only do blade guards limit the risk of serious laceration injury, they add flat plate drag area and reduce the aircraft’s terminal velocity.”
The FAA said a study on airborne collisions will be released in the summer.