Just before the Christmas holidays in 2018, the UK's second largest airport, Gatwick, was shut after drones were sighted near the runway. In total, some 1,000 flights were either diverted or cancelled, affecting 140,000 passengers as the airport was shut for a total of three days.
It brought the challenges posed by what is still a relatively new technology to the public's attention, with the airport's Chief Operating Officer Chris Woodroofe highlighting the growing threat posed by drones.
"I think what's clear from the last 24 hours is that drones are a UK aviation issue, or even an international aviation issue," Chris Woodroofe said.
"We have had the police, we have had the military seeking to bring this drone down for the last 24 hours and to date that has not been successful."
It was an incident with huge financial implications for both the airport and airlines, with the estimated cost of the shutdown put at around $64.5 million. It also resulted in several hundred thousand pounds of costs for local police forces. The incident is far from an isolated one, with similar incidents in Canada, Dubai, Poland and China highlighting the scale of the risk.
The threat is exacerbated by the growing availability and affordability of drones on the open market, which coupled with the general inadequacy of current counter-measures, mean that airports are at particular risk of disruption. While to date, the risk has mainly been a financial one, the prospects of a fatal collision between a drone and a passenger aircraft are all too evident, especially as numerous terrorist organizations have highlighted the potential for drones to carry a lethal payload.
Stopping drones in their tracks
It’s no surprise that the Federal Aviation Administration (FAA) have recently announced plans to evaluate a range of technologies that could be deployed to not only detect drones, but mitigate the security risks they pose.
The project is part of the Research Program for Detection and Mitigation of Unmanned Aircraft Systems in Airports that is run by the agency, and they hope to test a minimum of 10 different technologies by the end of the year.
Intercepting drones is not a straightforward task. The FAA, along with the Federal Communications Commission, and the Departments of Homeland Security, recently warned airports against jamming radio communications because this violates federal wiretapping laws.
So, assuming that Dutch plans to use bald eagles to take down drones are not likely to fly, what options are there?
Arguably the biggest challenge for stopping the misuse of drones is the small size of most drones on the market today. This presents a clear challenge in terms of spotting, and then nullifying them. What’s more, drones are increasingly able to use thermal imaging to operate successfully at night.
Two approaches that have been largely tried and discarded involve sending objects up to destroy the drone.
These include sending up another drone to intercept the rogue unit and cause it to crash, while some form of missile has also been tested. These cause an obvious challenge in that they result in the target drone falling from the sky, which can produce significant safety hazards in its own right. It also makes the rogue drone harder to retrieve, which is important for legal purposes.
Another approach is to try and manipulate the software in some way, or alternatively to interfere with its electromagnetic operating range. Both approaches have the advantage of not requiring law enforcement personnel to be present for the procedure. One common approach is called geofencing, which involves the creation of an invisible electronic fence that prevents the drones from flying into particular areas.
These locations would need to be programmed into the software of each drone by the manufacturer, so would require collaboration in the event that airports and other high risk destinations are not legislated by government regulation. Even should that occur, however, there are concerns that drone pilots can bypass the software and overcome any restrictions.
Jamming has also been considered in the past, with an electronic signal effectively preventing the GPS system of the drone from functioning, thus confusing the drone. Of course, such approaches don’t discriminate, and can therefore affect the GPS of other users in the area, so are likely to remain illegal for some time. Another approach for fooling the GPS system of the drone involves hacking into it to effectively take control of the device. Again, it’s not an approach that is likely to have widespread adoption.
To date, an ideal solution has not really been found, so it will be interesting to see what emerges from the FAA’s attempt to find a reliable and robust way to keep airports free from drone-based disruption.