DJI Calls FAA Data 'Poorly Chosen' and 'Deeply Flawed'

DJI recently issued a white paper expounding upon the relationship between the weight of drones and the risk posed by them, asserting that current FAA regulations are based on "poorly chosen data and deeply flawed assumptions." 

The white paper proposes raising the 250-gram threshold that defines drones of the lowest risk to 2.2 kilograms. For reference, the DJI Phantom 4 Pro weight 1.39 kilograms and the Inspire 2 weighs 3.29 kilograms, making the proposed raise in the threshold somewhere above the standard consumer range. The original 250-gram threshold was developed in 2015 during the process of creating registration guidelines for drones. Any drone below this threshold was considered a sufficiently low risk to not warrant registration. Regarding this, however, DJI claims:

While the FAA’s 2015 Registration Task Force (RTF) said drones weighing up to 250 grams posed the lowest risk, further research shows that standard was based on poorly chosen data and deeply flawed assumptions, including an almost 50-year-old model of casualties from a nuclear war that destroys all hospitals. Using more accurate scientific inputs, DJI’s white paper concludes unmanned aircraft systems (UAS) up to 2.2 kilograms can be safely flown with the lowest risk.

DJI Vice President of Policy and Legal Affairs Brendan Schulman says that the 250-gram threshold was created merely for registration, but was inappropriately adopted for the purposes of safety guidelines. The white paper asserts that a 2.2-kilogram line is more appropriate, especially given that issues of the presence of people and pilot aptitude seem to determine the frequency and outcome of safety-related incidents more so than weight. Such thresholds are important as they guide the creation of laws that determine the operational limits that drone flyers must work within. 

[via Drone Life]

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JB Kramer's picture

Just imagine a 2.2 kg (roughly 4.5 pounds) mass dropping on your head from 300 ft up. Something that could easily happen with a complete power loss on one of these drones. This would be roughly like someone dropping a 5 pound bag of potatoes on you from 30 stories up.

I have no idea what the terminal velocity of one of these drones is but a human falling has a terminal velocity around 120 mph or 200 kph. And humans it seems to me would generate a lot more drag than one of these aerodynamically smooth drones.

Whatever you want to call this but minimal risk isn't it.

Paolo Veglio's picture

My guess is that anything that falls from the sky is potentially dangerous.
Just to put some numbers on paper, a sphere of 10 cm radius that weights 250 grams (as the FAA limit) has a terminal velocity of about 60km/h.
Since a drone is far from an ideal sphere, which has one of the worst drag coefficients btw, I imagine that 60km/h can be probably doubled to get a reasonable estimate of the drone's terminal velocity. Oh, and it should be able to make it to that speed before crashing on someone's head, if my math is right.

I think FAA's main concern is not about drones falling from the sky but rather of them hitting planes, otherwise they wouldn't let people fly anything

Chad T's picture

Actually neither of the comparisons (5 lb sack of potatoes or your 10cm 250g sphere) are correct with regard to the aerodynamics/terminal velocity of a drone. Unpowered, a quad-copter has a very high drag during freefall, due to the windmilling props, similar to how a maple key flutters down. The windmilling props stabilize the drone onto its "draggiest" axis, and slows it down considerably. So as a comparison to your 10 cm sphere, it would be significantly slower.

I've tried it before with my small toy quad, and it would fall slowly enough to be able to catch it if you tried. It wouldn't cause any lasting damage even if it clocked you in the head. Mid sized drones like a DJI Phantom... yeah it would definitely hurt, but not kill you. Commercial sized drones would definitely be a hazard though, although it would be interesting to see how the extra props of a hexa or octa-copter would reduce the terminal velocity.

It would actually make for some interesting experiments to measure the terminal velocity of an array of drones if I had the money to smash several thousand dollars worth of them.

Paolo Veglio's picture

that actually makes more sense. For some reason I thought that a drone in free fall would turn on one side

Brian Hawkins's picture

There's a lot more to determining risk than momentum. Read the white paper. It will change your mind.

Adam Non's picture

Seems to me the risk is the propeller. Regulations and licensing should pertain to the vehicle performance metrics (size, weight, speed, blade design, protective shrouds) as well as the operational use (racing, photography, aerobatics) and situation (real estate sales, commercial photography, herding livestock.) I'd say anything heavier than an acorn falling out of a Oak tree is painful ... put a spinning propeller on the acorn and you've got more than a bump on the noggin.

Spy Black's picture

Maybe they should smash the well-below 2.2 kilogram DJI Phantom 4 Pro onto the head or into the face of DJI execs to have them make their case...

Kristopher Rowe's picture

Wow. The drone hatred is strong with these commentators thus far.

Smashing a drone in anyone's face is not acceptable behavior. Why do you have such disdain for drones and the industry?

Spy Black's picture

Boy, that was ROYALLY right over your head, wasn't it? No pun intended...

Tim R's picture

It's a known fact that 21% of pilot errors or drone malfunction result in falling drones hitting people directly in the head.

Cou Yon's picture

I find it hilarious to see that DJI thinks they are remotely relevant at all in any of this! Just because you are the top drone manufacturer on earth still doesn't mean a thing next to manufacturers that build transportation that carries a human!

I wish one of the other drone manufacturers would get their $hit together and produce a drone worthy of competition to DJI so we could get somewhere!

DJI is the worst customer support company on Earth. They sell us drones and then sell us an instant replacement warranty so they don't have to talk on the phone. Not saying that's stupid because they are making money hand over fist, but I think they need to shut their yapper and go concentrate on delivering drones than fighting with the FAA.

Adam Non's picture

The government uses "domain experts" in all regulation, policy and law -- DJI is surely a recognized authority. That certainly does not mean you take their assertions verbatim (that kind of thing is the luxury of billion dollar industries with lobbyists and politicians in their back pockets ... oil, gas, banks, insurance, patents, military ...)

LA M's picture

It's not about the size/weight of the's the operator's behaviour. The law doesn't care if you drive a compact car or a huge SUV. It's how you drive that dictates your fines or loss of privilege. Sheesh.

Adam Non's picture

Size matters! There's no license for a bicycle, but there's helmets and lights and other regulations or expectations of safe conduct. I'd say this is the "toy" end of the drone market.

There's less fines and fees for small cars than large ones, even higher revenue from commercial use of the same size vehicle and higher again for trucks and buses. This would range from the drones with propeller guards and safety precautions (anti-collision sensors, return to base, etc.) to the pro-sumer drones in commercial use.

Size is the most common metric for laws, fines, fees and penalties or punishment. Causing an accident with a motorcycle is less than the same crime committed with a car, and less than involving a truck.

Crash a tiny "pocket selfie" drone into a passerby by misfortune, oh well, but lose control of a drone for any reason and have it fall into a live event crowd, even though you might be operating with all the right licenses, permits and insurance, I'd say you should expect to need a lawyer and face the liability.