UK: Europe based organization that represents the majority of civilian drones manufacturers, Drone Manufacturers Alliance Europe (DMAE), has called the United Kingdom Department for Transport (DfT) to release the full testing methodology and results of its Mid-Air Collision Study, in order to better understand how to mitigate the risks drones may pose to traditional aircraft.
DfT released an 18-page summary of its testing results last week, which appears to indicate that the vast majority of consumer drones in the market today pose limited risk to civil aviation in general and to commercial airliners in particular. However, the summary left many questions unanswered about its methodology, modelling and results, making it difficult to use its findings as the basis for discussions about drone technology and regulations.
“DMAE strongly believes drone regulations should be based on scientific studies that quantify risk in order to minimize it. Unfortunately, these tests were conducted in secrecy, and the organizations involved have not published their results in detail or submitted them for peer review,” said Daniel Brinkwerth of DMAE. “This summary does not provide an adequate basis for designing safer drones or protecting the public. We ask DfT and its testing partners to publish their methodology and results, so drone manufacturers as well as regulators can use the full data set to improve public safety.”
DfT, the Military Aviation Authority and the British Airline Pilots’ Association commissioned the mid-air collision study, which was conducted by QinetiQ and Natural Impacts. It compared how helicopter and airliner windscreens would withstand impacts with four classes of drones, weighing from 400 grams to 4 kilograms. The summary raised few concerns about the smallest drones that are most prevalent in the skies, and noted that the plastic housings of many drone components served to absorb impact energy and reduce the severity of a collision. However, it is unclear what specific drones were used, or exactly how they performed in their impact tests.
“Some of the most alarming findings in DfT’s summary are based on an object that resembles a javelin more than a drone,” Brinkwerth explained. “The study’s authors could not find a way to launch a 4-kilogram drone against an aircraft windscreen, so they mounted two motors, a heavy camera and an oversized battery on nylon arms. This object could never fly, much less encounter an airliner at high altitude. Researchers need access to the full test results to understand whether this is an acceptable shortcut for scientific research.”
The DfT summary stands in contrast to the most detailed scientific study of drone collisions to date, released in April by a United States Federal Aviation Administration research center. DfT’s summary results indicate airliners would face the largest risk from drones while flying at cruising speed, but that would occur above 10,000 feet elevation, where they would be unlikely to encounter a drone. Lower to the ground, they would be flying at slower speeds, further minimizing risk.
Helicopters would face different risk, since helicopter windscreens are not required to be strong enough to withstand a collision with a bird. Regulators have long recognized this deficiency, and one European Aviation Safety Agency report considered requiring helicopter pilots to wear helmets and visors in order to protect against bird strikes. Both UK and EU regulators suggest introducing height limits for drones to mitigate potential threats from drones for helicopters.
The summary of the Mid-Air Collision Study acknowledges that the research did not attempt to estimate the likelihood of a traditional aircraft colliding with a drone. As a matter of principle, risk-based policies always draw on an assessment of both potential damage and the probability of its occurrence. “There have been no confirmed collisions anywhere in the world between a modern consumer drone and a traditional aircraft, and drone manufacturers are working diligently on technological solutions to prevent any such collision,” Brinkwerth said.
“Many of the shortcomings in this summary report could have been addressed during the research process with more robust participation from all stakeholders. All the major drone manufacturers stand ready to assist with further studies by providing materials for testing as well as research assistance from our experts,” Brinkwerth concluded.