Light up the drones

When you couple the increasing popularity of night-time HEMS with increasing drone sales to the general public, you get a rising risk of a night-time collision between a UAV and a helicopter air ambulance. James Paul Wallis asks whether it’s time for drone makers to upgrade the anti-collision lighting on their craft to show up under NVGs and infrared.
The June edition of AirMed & Rescue Magazine (Issue 77) featured an article on how manned aircraft can safely share air space with remotely piloted drones. Penned by Susan Smith, Ty Le Roy and Nick Mattheisen, it included the line: “The LED lights on most drones are not visible with night vision goggles and are often disabled by the operators.”
My initial research suggested that this topic has not been addressed by aviation authorities or drone manufacturers. I swiftly climbed atop my soapbox and used my editor’s comment to call for all drone aircraft to be fitted with LEDs that show up not only to the naked eye, but also through NVGs and infrared cameras, and that cannot be disabled by the operator.

“The LED lights on most drones are not visible with night vision goggles”

Real risk?
Now, you may be thinking that this suggestion is an unnecessary requirement, given that most drone users are prevented by regulations from flying at night. For example, the US Federal Aviation Authority’s much heralded Small unmanned aircraft rule (Part 107) stipulates that UAVs can only be flown during daylight or civil twilight (defined as 30 minutes before official sunrise to 30 minutes after official sunset, local time). However, as I argued in the comment, of all pilots, the civilian drone user is the least likely to feel bound by regulations (see for example the recent furore over super-vlogger Casey Neistat’s use of quadcopters over New York City).
Another obvious objection would be that the anti-collision lights on manned aircraft are typically not required to show up under NVGs/IR, so why should such a restriction be placed on UAVs? Well, frankly, because even without the lights, a pilot using enhanced vision has some chance of spotting a manned aircraft due to its large size and/or hot engines, whereas small drones are likely to be virtually invisible in the same conditions.
Quizzed on this, Denise Eikelenboom, managing director and co-founder of Drone Flight Academy, showed support for change: “If you make lighting mandatory, make it NVG/IR visible: the operators who experience the most problems with drones are the operators that fly VFR night and thus most probably use NVG and/or IR.” She added: “From personal experience, I know that a light is the best way to see another aircraft – or drone for that matter – during night ops.”
The UAV manufacturers I contacted demonstrated a range in their awareness of the issues I raised. For example, Parrot, maker of machines including the Bebop 2 quadcopter, would only say that the camera drone’s rear-mounted light has not been tested for night vision visibility.
Meanwhile, DJI initially told me, somewhat enigmatically: “You should be able to see [the LED indicators] through night vision, but you can also see it in the dark without the support of night vision.” Pushed on the NVG/IR point, Christian Struwe, DJI policy lead europe, added: “DJI is committed to safety and encourages safe use of our products. However, we cannot at this time comment on specific safety suggestions applying to all parts of the drone market … Our newer generations of drones are equipped with LEDs, making them highly visible at day and night.”
The clearest response came from Aeryon, maker of the camera-carrying SkyRanger quadcopter, whose spokesperson said: “The Aeryon SkyRanger does come with configurable safety lighting and different packages that show up both to the naked eye or under NVGs. For government and military uses we offer an IR LED lighting system that will show up under specific night goggle specifications including NVGs. This is a quite narrow range of consumer, however, and usually these capabilities are only required for tactical operations outside of a nation’s airspace. We will continue to offer configurable lighting systems and implementation of hardware visible under aviation NVGs.”

of all pilots, the civilian drone user is the least likely to feel bound by regulations

Under conventional thinking, Aeryon’s approach makes perfect sense: LEDs visible to the naked eye for standard civilian uses; NVG/IR-visible LEDs for tactical ops where, perhaps, you might only want the drone to show up to personnel using enhanced vision gear. However, that doesn’t address the risk of misuse of amateur drones in civilian airspace.
Last but not least, what of INAER Spain, which is developing a 150-kg (330-lb) remotely piloted helicopter with the express intention of using it at night (AMR Issue 78, July 2016, INAER Spain to use UAVs for fire spotting)? A representative said: “We only need lights in the UAV to be seen by the pilot on ground. Regarding the mission that will be carried out during the night, this will be a pre-planning flight to obtain information about the evolution of the fire in order to obtain the attack plan for the sunrise.” In other words, the firm will be relying on the risk of conflict being low, as the drone is only to be used where air traffic is being closely controlled as part of firefighting efforts.
Cost – voluntary vs imposed
One point to note is that the cost of upgrading drones’ LEDs could be low – but spiral if this becomes a regulatory requirement. Nick Rice, managing director of lighting specialist Consolite Techology, advised: “The process for manufacturing an LED that would be visible in the IR is not complicated. The complication comes when it becomes mandatory and then regulated, at which time a specification would be written and, in all likelihood, become an EASA/FAA standard.” Such a standard would likely be demanding, said Rice, specifying for example intensities at particular angles, use of specialist testing equipment and regular company audits.
He continued: “Whilst aerospace lighting manufacturers are used to these requirements, the overheads of running a company with the relevant certifications are quite high due to these needs. This may make the unit price seem quite high when compared to the original, raw LED.”
So, there is potentially a window of opportunity here, drone makers. Opt now to adopt NVG/IR-visible anti-collision lights while the costs are low. If night-time collisions or near-misses with manned aircraft prompt the regulators to act, the price tag could escalate dramatically.
Currently, the extent to which aviation authorities have sought to regulate drones varies. For example, the FAA’s recent ruling requires UAVs to bear ‘appropriate anti-collision lighting’ (though note that, as above, the rule assumes daylight-only ops).
On the other hand, Richard Taylor, a representative for the UK Civil Aviation Authority, revealed: “At the moment, we do not have any oversight of the airworthiness of drones and so have no powers to make collision lights mandatory. Clearly, if drones are to be integrated into the airspace system, then they will indeed require identification markings, collision lights etc, but we are some way off that at the moment.”

“If you make lighting mandatory, make it NVG/IR visible”

Going further
While upgrading drones’ LED lighting would increase safety, there are other options on the table to reduce the likelihood of manned/unmanned aircraft conflict. For example, Eikelenboom stated: “I would suggest to make a transponder mandatory as well. This will make the full integration of drones into our airspace possible in a safe way.”
Compared to altering the LEDs, adding transponders could have greater cost, weight and power-draw implications (although minitiarised, low-power versions are being developed for UAVs). But an interesting side-effect would be that (depending on transponder type) the UAV’s location – and registration number – could show up not just to nearby aircraft, but also to the authorities such as air traffic control. I wonder what Casey Neistat would make of that.