Sky News 

Gatwick Airport is the UK's second busiest flight facility after Heathrow. On December 19, it was accommodating thousands of holiday travellers. Around 9 PM, an unmanned aerial vehicle (UAV), commonly known as a drone, was sighted in the airspace dangerously near the airport's single runway. Just this year, the UK prohibited drone flights within 1 kilometre of airports and this drone was well within that limit.

No details are yet available about exactly what kind of drone it was. But it was large enough (or its lights were bright enough) to be seen at night. The airport authorities, acting with prudence, ordered a temporary shutdown in the hopes that the drone flight was an isolated mistake that could be dealt with quickly. Unfortunately, that wasn't the case.

Shortly after flights were resumed, another drone was sighted. Eventually, observers logged over 50 separate drone sightings, and the airport was shut down for a total of 33 hours before the last drone went away and flights were resumed. A couple living near the airport were arrested in connection with the incidents, but were released without being charged.

Because Gatwick is a key hub in so many airline networks, the shutdown affected over a hundred thousand travellers and sent ripples in the air-transport system around the world for days. Eventually, the authorities mustered military equipment capable of both locating and shooting down drones, but by that time the threat had ceased.

This incident raises a number of questions about what the proper policies of airports should be about drone sightings, about what regulations drone users and manufacturers should have to deal with, and how we are going to prevent copycat drone incidents in the future.

First, the policy question.

It looks like the UK is somewhat behind the US in its regulation of drone technology. For several years, the US Federal Aviation Administration (FAA) has required registration of ownership of drones (at least those above a certain size and capability), and laws are already in place restricting drone flights above certain altitudes and near airports. The US has had incidents of drones near airports, but no long-term shutdowns of major airports comparable to Gatwick.

It's possible that the UK authorities erred on the side of excessive caution in ordering a total shutdown of the airport. Depending on the size of the drone, they might have opted merely to warn pilots that there was a drone in the vicinity, as there are birds whose weight and consequent hazards to aircraft are comparable to that of a small drone -- and it is rare to see airports shut down because of excessive bird flights over the landing areas. But birds don't carry explosives, and terrorist fears were probably prominent in the decision to play it safe and simply shut down the single runway rather than run the risk of having a plane damaged or destroyed by a bomb-carrying drone.

That being said, what could authorities have done to prevent the drone pilot (or pilots) from flying their UAVs in restricted airspace? Presently, not much, short of trying to shoot them down. There is electronic fence technology available, but depending on the radio frequencies used by the drones, attempts simply to jam the frequencies typically used by drones could have severe unintended consequences, even possibly disrupting electronics that are vital to legitimate air operations. And if the drones were pre-programmed to follow a set flight pattern, they do not even have to be in constant communication with the drone's operator to fly, and therefore jamming might not have done any good.

Going aggressive and trying to shoot the thing down is not that easy. A drone at a distance of a kilometre or so is a very small target. If a bullet or rocket misses it, that bullet or rocket is going to come down somewhere, and typically metropolitan airports are not places where you want bullets or rockets coming down at random. So that's not a realistic option either.

The best long-term solution might be to build in something called "remote ID" that the world's largest drone manufacturer, DJI, suggested in a statement. Remote ID would be a system whereby all drones would transmit their location, the pilot's location, and an identification code in real time. If such a system were made mandatory, authorities could simply read the code and run over to where the pilot is and arrest him or her. It's interesting that the biggest drone maker has suggested such a solution, but it obviously hasn't included it in their products yet, possibly for cost and performance reasons.

Low-end drones don't have GPS receivers and wouldn't be capable of remote ID, but maybe those types are not the most serious threat to places like Gatwick anyway.

Even with such ID technology, a determined drone pilot could keep on the run and stay ahead of the cops long enough to cause serious disruption. And chasing down more than one drone at a time could be hard. Because drones can typically stay in the air for only half an hour before their batteries have to be recharged, the number of drone sightings during the Gatwick shutdown leads authorities to believe that several drones and operators were involved.

The investigation continues, and it will be interesting to discover who did it and why. In the meantime, the UK has had a rough wake-up call with regard to their policy on drones. One hopes that they don't overreact with blanket bans on the devices, which are proving to be useful in a wide variety of commercial and amateur applications.

But we can't have major airports getting shut down at the whim of a few people with consumer-grade drones. So the policy and regulatory environment, especially in the UK, will have to catch up with drone reality on the ground—or rather, in the air—to prevent such incidents in the future.

Karl D. Stephan is a professor of electrical engineering at Texas State University in San Marcos, Texas. This article has been republished, with permission, from his blog Engineering Ethics, which is a MercatorNet partner site. His ebook Ethical and Otherwise: Engineering In the Headlines is available in Kindle format and also in the iTunes store.