As reported by Alan Levin of Bloomberg News, researchers at Virginia Tech have concluded there is less than a 5% chance of catastrophic head injury if a person is hit by a drone weighing less than 2.6 pounds (1.2 kg). Although this may embolden some in an effort to loosen regulations regarding the flight of consumer drones above crowds, a more critical analysis of these results leads to a different conclusion.

First I would like to see a show of hands. How many of you want to be the 1-in-20 person who DOES get the catastrophic head injury? 1 chance in 20 is not a negligible risk by any stretch of the imagination (in manned aircraft, by comparison, negligible risk is typically characterized by 1 chance in 1 million). If the regulations are irresponsibly loosened as a result of this study, the occurrence of drones falling on humans will inevitably increase (more of my thoughts on this are here). In addition, the people in a given crowd are unable to “opt out.” Unlike an elective surgery where the patient weighs the risks and benefits of the procedure, the people in the crowd below the drone do not have much of a choice. If you are attending an outdoor event, besides the annoyance of having a mechanical object buzzing around above your head, should you be forced to make the conscious decision of whether to stay or leave if someone else in the crowd decides to bring their drone?

Furthermore, the current recreational drone regulations permit consumers, without any licensing, to operate drones weighing as much as 55 pounds. This weight limit is a legacy of by-gone days when the only amateur drone operators were radio-controlled (RC) airplane enthusiasts. As I have discussed previously, the RC community was very effectively self-regulated prior to the advent of modern consumer drones. Although a $1500 DJI S1000+ (pictured above) is not a toy, it’s maximum weight (with payload) of 24 pounds does mean it can be flown, for recreational purposes, without a license. When testing this model, the Virgina Tech researchers found the likelihood of catastrophic head injury was 70%.

Although the vast majority of individuals can and do act responsibly, meaningful regulation, with effective enforcement, is still needed to protect the public. Prior to being struck down by the courts, the FAA’s drone registration program did not require registration of drones weighing less than half a pound. Drones under this threshold are quite reasonably considered to be toys and presumably pose a negligible safety risk to the public. Where should the safety cut-off be in terms of drone size? Possibly greater than 0.5 pound but certainly less than 2.6 pounds, at least based on Virgina Tech’s data.