The US Federal Aviation Authority (FAA) has published the results of a study into the threats to manned aircraft posed by drones. Its findings contrast with those of a similar collision study carried out by the UK’s Department for Transport, and could provide the foundations for evidence-based regulations moving forward.
What if? That’s the question being asked by commercial airline pilots and the wider public. What if a photography drone was involved in a collision with a manned aircraft, for example? Regulations regarding where drone pilots can fly, how high they can go and whether or not operators should be put on a register all seem to stem from that one question.
There are concerns over privacy and the safety of people on the ground should anything go wrong, but the main driver for tougher regulations on drone pilots has been the rise in ‘near-misses’ with larger aircraft – something that usually takes place in the airspace around an airport.
Although the topic receives plenty of media attention, there have only been two confirmed cases of a drone collision involving manned aircraft.
Controversial UK drone collision study
Back in July, the UK’s Department for Transport released a summary paper of a study that sought to justify tougher measures on drone pilots. The research was used to justify a relatively low weight threshold of 250 grams, which if exceeded, would require the pilot to sign up to a new registration scheme and an enforced safety test.
The British government-funded study received plenty of criticism, particularly with regards to its methodology and the way testing appeared contrived to come to overly dramatic conclusions that would justify the new policy announcements.
“Some of the most alarming findings in DfT’s summary are based on an object that resembles a javelin more than a drone,” said DMAE spokesman Daniel Brinkwerth at the time.
“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.”
“This summary does not provide an adequate basis for designing safer drones or protecting the public.”
The US collision study results
This week the FAA’s drone research divison, Assure, released the findings of its own study into the dangers of drones colliding with larger manned aircraft.
The findings are somewhat inconclusive and the researchers admit that much more needs to be done. However, they do suggest what most people with a basic understanding of physics would already know: that damage caused depends on the size of the drone and the speed of the impact.
Assure’s results found that a collision involving a 1.2kg quadcopter and the windscreen of a commercial jet airliner travelling at 250 knots would not cause any serious damage. Most at risk in the case of an impact would be the horizontal and vertical stabilizer on both passenger planes and business jets.
“Smaller drones such as those made by DMA’s members would cause less damage than larger drones, and airplanes flying at relatively slow speeds, as they do in the low altitudes where most drones operate, would also suffer less damage,” said Kara Calvert, Director of the Drone Manufacturers Alliance.
“Drones have an admirable safety record and this research confirms they can continue to safely share the skies with traditional aircraft,” she continued.
Further research hovers on horizon
Although the FAA study leaves plenty of questions unanswered, it should go some way to reassuring the public and ease concerns surrounding the use of drones near airports. Assure is scheduled to continue researching through until 2021.
The clearest conclusion from the US study that can be drawn is the inadequacy of the UK Department for Transport’s own work. The findings suggested that the make-up of the drone, not just its total weight, is key to its potential threat – something the UK study failed to take into account.
The foundations for revised UK drone legislation due in the Spring are therefore sketchy at best.