Many drones weighing more than 250g are little more than toys. Do they really pose a risk to the airspace?
To explore this question, we examine 25 years of data from the FAA’s wildlife strike database. Although aircraft collide with birds many thousands of times per year, only a tiny fraction of those collisions result in damage to the aircraft, much less human injuries or deaths. The most serious reported incidents typically involved flocks of large birds. In more than 25 years of data, only 12 wildlife strike incidents resulted in fatalities.
Since the addition of UAS to the airspace is similar in many respects to an increase in the bird population, we conclude that the risk to the airspace caused by small drones (for example, weighing up to 2kg, or 4.41 pounds) flying in solitary formation is minimal.
Our analysis has been based on actual bird strikes, not near misses or simple sightings. We find in general that small UAS under 2kg pose a negligible risk to the safety of the national airspace. We estimate that 6.12×10−6collisions will cause damage to an aircraft for every 100,000 hours of 2kg UAS flight time. Or to put it another way, one damaging incident will occur no more than every 1.87 million years of 2kg UAS flight time. We further estimate that 6.12×10−8 collisions that cause an injury or fatality to passengers on board an aircraft will occur every 100,000 hours of 2kg UAS flight time, or once every 187 million years of operation. This appears to be an acceptable risk to the airspace.
As noted elsewhere, this is statistically rock solid. But there is always a gotcha and where the naysayers have a point is that birds and drones differ on intent. Not being an actual bird brain, I have to assume that birds are simply interested in survival. Drone pilots can have markedly different agendas. That said, drones are only one more way to cause damage, not the only way.
Want to do the math for yourself? You can download the complete paper here.