/ Drones

Drones: Too much, too soon?

Unmanned Aerial Vehicles (UAVs), more commonly referred to as drones, have become increasingly popular. They're fun to fly, to race, and the aerial footage they capture is absolutely stunning. They're also surprisingly dangerous.

US drone strikes have taken out many notable terrorist leaders and followers. Their ability to lurk undetected, gather valuable intelligence and conduct operations with no risk to their operators is highly prized by the military. Granted, those are million-dollar military drones armed with Hellfire anti-tank missiles and piloted from the opposite end of the world . But they share some important characteristics with commercially-available drones: they're dangerous yet elusive.

These capabilities have caught the eye of many terror groups, which have obtained and weaponised drones of their own. The Islamic State has long used hobby drones for reconnaissance, but last year begun using to stage attacks. 2 Kurdish fighters were killed in October 2016 after a Daesh drone they captured blew up- the first fatal drone attack by a terrorist group. Since then, many other extremists have used commercial drones to carry grenades, mortar shells and IEDs, with fatal consequences.

Civilian Drone Use

In less tumultuous parts of the world, where grenades and C4 explosives aren't easily available, regular civilian use of commercially-available drones has also caused near-misses, unnecessary alarm, and occasionally serious injury.

The USD $1000 DJI Mavic Pro has a top speed of 65kmph, with 4 blades spinning 5,500 times per minute. The effective speed of the outermost tip of the blade (i.e. the bit that collides with oncoming objects) is therefore approximately 60m s-1. That's enough to cause lacerations. Online forums abound with posts by drone owners wondering about the safety of catching drones by hand, accompanied by several unfortunate accounts by owners who've learnt the answer the hard way.

To mitigate this hazard, several commercial drones like the DJI Phantom and the Parrot AR have plastic propellers that bend upon impact for minimum damage. Drone manufacturers also sometimes include propeller guards or sell them separately. These can be attached to the drone to prevent contact between the blades and oncoming objects. But many people don't purchase these safety propeller guards or fail to install them on the drone because of the added bulk or poor aesthetics.

drone with safety guard
Drone with propeller guard attached

Drones without propeller guards abound, and have chipped noses, sliced fingers and even blinded a toddler.

Civilian Drones in Terrorists' Hands

Drones aren't the most cost-effective way to strike terror into a population. Why buy a $1000 drone and hope its whirling blades will slice a couple of fingers when a $10 knife in City Hall during peak hour could cause way more casualties?

The true value of a drone lies in its ability to delivering a payload past ordinary security measures. By virtue of their small size, drones are difficult to detect from a distance with the naked eye or with conventional radar and are hence often able to fly undetected across walls, fences, and territorial boundaries.

In 2013, a Parrot AR quadcopter flew close to German Chancellor Angela Merkel during a rally before crashing near her feet. A small explosive charge aboard the drone could have taken out the Chancellor and her nearby Defence Minister in one fell swoop.

In 2015, a White House radar system designed to detect flying objects failed to pick up a small drone, about 60cm in diameter, that crashed into a tree on the South Lawn. Researchers have since demonstrated the DJI Phantom that crashed could have carried a 1.3kg explosive payload, enough to take out the President during one of his walks around the grounds.

At a top speed of 95kmph a drone rigged with an IED could fly across several blocks within minutes before plunging into a crowd, or towards a speaker at a podium. A payload laced with VX, anthrax or a radioactive substance would be unthinkable.

But how would a Singapore-based attacker lay their hands on bomb-making materials or dangerous substances? With less difficulty than you might think- drones don't respect territorial borders.

drone flight radius

A DJI Phantom (green circle) can reach Northern Singapore from Johor Bahru; anywhere in Singapore is viable target for a Skywalker X-8 (red circle) from Kluang, Batam or a ship in the South China Sea.

Quadcopters' flight time of about 20 minutes limits their range somewhat, but half an hour at a conservative 50kmph is still enough to make it from JB to the CBD. Hobbyist plane-like drones have much greater endurance. The Skywalker X-8 retailing in kit form for USD 170 can fly for nearly 3h across 155km, more than enough for 2 round trips between Batam and Singapore. Explosives and toxic agents might be more easily obtainable in Malaysia or Indonesia than in Singapore. Such drones could transport a hazardous payload directly towards a target or deliver it to a waiting plotter for future use.

More reasons to fear drones


Drones are eminently hackable. Their onboard computers are as vulnerable as any other, including to the recent KRACK. Their tendency to process GPS input at face value without question also renders GPS spoofing very effective. Messing with a drone's ability to position itself can wreck havoc on its flight path, or if done in a sophisticated manner, direct the drone along a new flight path.

Many popular drones including the Parrot AR and DJI Phantom have been hacked already, with attackers able to take full control over their flight path. Even military drones have fallen prey. In 2011, Iran navigated a CIA UAV safely down to the ground by manipulating the aircraft's GPS coordinates.


Drones are programmable and autonomous. Once set in motion, a well-programmed drone will move inexorably according its predetermined route, without external control, ignoring all incoming signals, and possibly even without GPS. This means the usual battery of signal jammers, hacking devices and GPS blockers might not be of any use in grounding a rogue drone.

Furthermore, drones can be programmed to move in concert. By pre-programming set flight paths, a sophisticated attacker could set tens or hundreds of drones in motion at the same time, orchestrating simultaneous attacks at several locations. Swarms of drones could enter a MRT station from different entrances at once, cutting off all exits. Or even attack MRT stations across the island at a set time, all without human involvement. Mini programmable quadcopters can be had for as low as USD 14. Attackers with thicker wallets will find popular Parrot and DJI drones are easily programmable too.

This is hardly futuristic technology. The NDP17 UAV light show featured 300 drones moving in formation whilst China flew 1,000 drones together during the lantern festival earlier this year.The US Navy has been working a military application through the aptly-named Low-Cost UAV Swarming Technology (LOCUST) programme.


Consumer drones' small size means they are easily mistaken for birds even on radar drone detection systems. According to Brian Hearing, founder of Droneshield LLC, radar systems are effectively useless for catching small drones. Increasing the system's sensitivity means it will also pick up passing birds and swaying trees.

Military surveillance technology is generally focused on the detection of large to medium-sized aircraft, rather than small consumer drones less than a metre in diameter. To address the drone threat, Singapore acquired the advanced Gamekeeper system that allows security forces to locate and track consumer drones within a 5km radius. Unfortunately, an operator might be piloting the drone from several kilometres away or even be sleeping at home while their drone flies autonomously. Security forces will have a tough time locating the perpetrator of a drone attack.

Furthermore, knowing is only half the battle. Rogue drones spotted still have to be taken down. Despite being "heard and observed" by a Secret Service officer, the drone that intruded on White House grounds in 2015 remained airborne because the Secret Service was unable to bring it down safely.

DJI Phantom

The USD 450 drone that eluded a sophisticated White House radar system

The US Air Force usually scrambles fighters in response to an unidentified aircraft in American airspace, but dispatching an F-15 is a disproportionate and ineffective response to a toy drone. Even supersonic jets from the nearest airfield will likely take around 10 minutes to arrive, giving a rogue drone a 10km attack radius. Assuming the F-15 manages to intercept the drone, there is little the multi-million dollar aircraft can do to take the $100 drone out. Firing upon it carries too great a risk of collateral damage. The drone will likely be flying too low for a clean shot or for the fighter to physically knock the drone out of the air.

Officers on the ground could fire at the drone, but discharging firearms at a small and fast-moving target is dangerous. Bullets that miss could hit a surrounding crowd or innocent passer-bys. Even a successful hit might cause an uncontrolled drone crash.

“Some of you have pointed out that attempts to shoot it down may actually cause more damage and I fully agree with you on that. So any action that we take, we have to consider it carefully

- Lui Tuck Yew, Transport Minister in 2015

Signal disruptors exist, but can't always be used without interfering with other wireless signals in the area, including cell transmissions and aircraft communications. Although most consumer drones are programmed to return home if they lose GPS signal, it's trivial to overwrite this behavior. Furthermore, some cheap drones fall right out of the sky if their GPS signal is disrupted, possibly onto passing pedestrians.

Hacking rogue drones is probably the most promising solution. Some drones use unencrypted WiFi, meaning a dedicated someone with the right hardware can take control of the drone. More secure drones can also be downed via GPS spoofing. It's effective when it works. Unfortunately, there are hundreds of drone models, each with their own quirks and eccentricities. In a time-sensitive situation, security forces will have to identify the drone and execute the appropriate hacking sequence within minutes. Unique DIY & hobby kit drones might require a custom solution- virtually impossible to create on the spot. In any case, vulnerable drones are vulnerable to all. A drone that can be hacked by our security forces is also one that can be hacked by an attacker.

If we can't ground drones once they're in the air, we must stop them before they are airborne.

What to do

Drone usage in Singapore generally does not require a permit for drones weighing 7kg or less that stay out of aerodromes and fly below an altitude of 200ft (about 61m) and are outside of designated security-sensitive areas, including venues designated for major events.

According to the Federal Aviation Administration in the US, it is illegal to operate drones for commercial purposes without a license whilst non-commercial flights under 400ft are only allowed for model aircraft within line-of-sight. Furthermore, all UAVs weighing more than 250g flown for any purpose must be registered. Many states, cities and counties are imposed further area-specific legislation that further limits the use of drones.

In the UK, drones cannot be flown within 50m of people, property or vehicles. Thailand has banned personal drone usage altogether. Those using drones for research or education must apply for a permit and meet a list of stringent criteria. Meanwhile, France has designated the whole of Paris a strict no-fly zone.

To promote safe, responsible drone usage, the local Civil Aviation Authority (CAAS) should consider some of the following regulations:

Registration & Tracking

A drone travels at vehicular speeds and can transport payloads of up to several kilograms in weight. If e-bikes must be registered, so should drones. CAAS should require registration of all drones above a certain weight (250g seems reasonable) to create an automatic identification system (AIS) similar to those used on marine vessels.

AIS Tracking Data around the Straits of Singapore
AIS Tracking Data around the Straits of Singapore as available on MarineTraffic. The identification, position, course and speed of all non-military vessels are available.

Drones should automatically transmit their unique identification within a radius of a few kilometres. This will facilitate detection and identification of drones by security forces and give them license to immediately down any drone not transmitting AIS data without waiting for it to exhibit threatening behavior. Knowing their drone is traceable will also encourage pilots to exercise more responsibility when flying. As an added bonus, the AIS system will also help pilots spot other drones more easily, reducing the possibility of mid-air collisions.

A License to Fly

Pilots should demonstrate competency in operating their drone and awareness of the safety guidelines before their drone is registered. Less experienced pilots should also be encouraged to attend a short drone-flying course so they are able to safely pilot their aircraft without endangering those around them, similar to China's flying test. If the drone enthuasists community grows substantially, the course and an accompanying test could be made compulsory to ensure new pilots can fly competently and responsibly.

Safety Guidelines

Drones flown in Singapore should meet certain safety guidelines at all times, including having soft bendable wings, propeller guards installed and an appropriate failsafe routine upon signal loss or low power. Instead of abruptly falling out of the air, the drone should land slowly and safely at the closest suitable spot.

They should also meet minimum cybersecurity requirements determined by Cybersecurity Agency of Singapore (CSA) to mitigate the risk a civilian drone is hijacked for nefarious purposes. Poor drone cybersecurity is valuable to security forces, but can be just as useful for a malicious actor.

Drones pose a real and present danger to the security of Singapore because of the ease they can bypass the usual fences, checkpoints and barriers. However, regulation is only effective with enforcement. The Unmanned Aircraft Act (and other legislation) can only prevent law-abiding pilots from accidentally causing harm. Laws won't stop a determined terrorist. More than anything, we need more research providing security forces real options to detect and safely deal with rogue drones in crowded Singapore.