In a newly released white paper, drone manufacturer DJI has concluded that the Federal Aviation Administration (FAA) set its weight standard “far too low” for determining which drones pose the lowest risk to people.
The FAA’s 2015 registration task force (RTF) said unmanned aircraft systems (UAS) weighing up to 250 grams (roughly .55 pounds) posed the lowest risk; however, according to DJI, further research has shown that that standard was based on “poorly chosen data and deeply flawed assumptions.”
Using what it calls “more accurate scientific inputs,” DJI says its new white paper concludes that UAS weighing up to 2.2 kilograms (roughly 4.85 pounds) can be safely flown with the lowest risk.
“The conclusions that flow from this analysis are twofold,” the white paper states. “First, the 250-gram upper threshold selected by the registration task force should be viewed as very conservative, given the general policy goals set by that committee concerning the probability of fatality upon human impact.
“The calculations were based on assumptions dating back 48 years about the lack of medical care in a thermonuclear war. These assumptions, which should have been rejected long ago as a basis for measuring UAS impact risk, result in a far higher estimated fatality rate than is realistic in a modern society.
“Second, adjusting just a few real-world factors, and accounting for actual kinetic energy transfer, compel a conclusion that the upper weight limit for a ‘lowest-risk’ UAS is nearly an order of magnitude greater: around 2.2 kilograms,” the report says.
“The RTF had only three days to decide how much a drone should weigh to require registration, and RTF members, including myself, unanimously set a 250-gram limit for registration purposes only, not for safety rulemaking,” states Brendan Schulman, DJI’s vice president of policy and legal affairs. Schulman co-authored the white paper with Walter Stockwell, DJI’s director of technical standards.
“Nevertheless, regulators around the world are using the FAA’s 250-gram limit as a safety standard for the lowest-risk drones, despite its flaws,” Schulman continues. “We hope our white paper spurs more detailed evaluation for better and more accurate rulemaking.”
In addition to reviewing the “surprising history” behind standard estimates of kinetic energy transfer and casualty risk, the company says, the white paper proposes more reasonable methods and data sources for calculating those figures.
“Given the faulty assumptions that underlie the selection of 250 grams, regulators should be hesitant to adopt a 250-gram UAS category without conducting their own rigorous safety analysis based on the desired policy goals,” the white paper concludes. “[A] review of the RTF’s work shows that its selection of 250 grams is far too low and far too conservative to be used to create a lowest-risk UAS regulatory category. Based on a similar approach to risk estimation, with adjustments for real-world factors, we propose 2.2 kg as the upper threshold of a ‘lowest risk’ UAS category.”
DJI prepared the white paper in December for use as a reference in further regulatory discussions around the world. It is available for download here.