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Virginia Tech has developed methods for testing how much damage a drone will do upon impact. | Source: Virginia Tech

Virginia Tech’s testing methods for drones have been accepted by the Federal Aviation Administration (FAA). These methods are the first to be accepted by the FAA since it’s latest rule for drone flights over people.

The FAA updated its rules for drone flight in December 2020. Before the ruling, the FAA didn’t allow drones to fly over people at all, a rule that hindered the industry since its implementation in 2016. The FAA did grant waivers for this ban, but the waivers were very narrow. They only applied to a specific set of circumstances, so each different type of application would require a different waiver.

In 2020, the FAA set aside its waiver system and instead laid out a universal standard for flying drones over people, while maintaining limitations for flying over large groups. If the drone couldn’t cause a certain level of injury, it could fly above people.

The ruling set out four categories of drones. All the categories stated that the drones couldn’t have any exposed, rotating parts that could lacerate human skin. Category one and two drones can be flown over people if they have a Remote ID transmitter. Category three drones can only be flown over people private areas that are either under covered structures, or have been warned that a drone is flying over. The fourth category is based on the drone having an airworthiness certificate.

The first three categories are determined by the amount of kinetic force the drone would transfer to something upon impact. The more kinetic energy the drone transfers, the more likely someone is to sustain serious injuries. Kinetic energy is determined by the drone’s speed and weight. However, according to Robert Briggs, chief engineer at the Virginia Tech Mid-Atlantic Aviation Partnership (MAAP), a FAA-designated testing site, this rule makes a big assumption.

“That assumption is that your drone acts like a rigid object — that when it impacts a person, there’s no frangibility, no deformation, no complex dynamics happening. For some drones, that may be a valid assumption, but for a lot of them, it’s not,” Briggs said.

This assumption prevents many drones from meeting the standard. Some drones are designed with intentional structural weaknesses that make them crack or break during impact. This dissipates the kinetic energy of the drone, and reduces the amount transferred to what it hit.

Virginia Tech’s Department of Biomedical Engineering and Mechanics worked alongside MAAP to develop testing methods to open the doors for more drone companies that still don’t meet the standard.

The newly approved testing methods determine how much kinetic energy a drone is likely to transfer in realistic conditions, which will take into account the energy that could dissipate with cracking or breaking. Now that the testing method has been approved, Virginia Tech can work with drone manufacturers to conduct tests and help design new models of aircraft.

“We’re really approaching this as a learning exercise,” Briggs said. “As we begin conducting this testing with various companies, we’re going to learn a lot about potential injury severity from small drones, including how it scales with size and design.”

MAAP has a history of firsts in the drone industry. In 2019, it worked with State Farm to receive the first nationwide waiver for drone operations over people and worked with Wing to receive the first drone air carrier certification.