There has been lots and lots of discussion about near misses between drones and passenger aircraft. We’ve heard about this happening in the US, the UK and other countries. (In the US, it’s enough of a hot button issue that Senators are showing their “concern.”)
Regardless of the number of near collisions that happen, what is the real risk? What sort of damage are we talking about and statistically speaking, how often do these collisions actually occur.
A recent study from George Mason University used data on bird strikes or bird collisions with passenger aircraft to estimate the amount of damage that a drone would cause if a drone and passenger aircraft collided in midair. You might be surprised to learn, according to the George Mason University researcher team, just 3% of collisions between aircraft and birds that are similar in weight to a small drone caused damage. According to BBC News, an “even smaller number caused injuries to humans, it found, and many of these were caused by flocks of birds.” Yes, smaller then 3%.
The research project was prompted by the recent introduction of rules in the US that make owners of drones weighing more than 250g register their craft with the US Federal Aviation Administration (FAA).
“Contrary to sensational media headlines, the skies are crowded not by drones, but by fowl,” wrote Eli Dourado and Samuel Hammond in an article summarising their research.
US airspace is home to about 10 billion birds, said the researchers, but collisions between fowl and aircraft have remained rare.
The pair analysed 25 years of data gathered by the FAA on bird strikes to determine what damage a drone might do.
Of the 160,000 bird strikes recorded since 1990, 14,314 caused damage, revealed the analysis. About 80% of the damage was done by birds such as turkey vultures and geese, which significantly outweigh domestic drones.
About 97% of the strikes that involved small birds did no damage to the aircraft they hit, said the researchers.
I think this really hits the nail on the head, “US airspace is home to about 10 billion birds, said the researchers, but collisions between fowl and aircraft have remained rare.” We’ve got less than 500,000 registered hobby drone operators and even less Section 333 Exempt approved commercial drone operators. Adding up all of the drone pilots, even including lots of fudge room for unregistered drone operators, the number is still no where near 10 billon.
That being said, there are obvious differences that need to be taken into accounts when comparing birds and drones. For example, while the weight may be similar, the materials are vastly different.
The study also covered the statistical liklehood of drone and passenger aircraft collisions.
If drones collided with planes in the same proportion as birds do – roughly one bird in one million – then it could be a long time before any drone-aircraft impact does damage, they said.
“One damaging incident will occur no more than every 1.87 million years of 2kg drone flight time,” said the researchers. Fatal incidents will be even rarer.
“This appears to be an acceptable risk to the airspace,” they concluded.
Similar to my comments above regarding weight versus materials, I believe it’s important to highlight a few differences that should be considered when trying to project the statistical liklihood of a collision. For example, no matter how often you fly your drone, any adult bird will have clocked waaaay more hours of flight time then you; this means obstacle avoidance and defensive flying is second nature. Another example would be considering the “Why?” drone operators would be flying in a certain area; people are event driven, and we’ve already seen firefighting aircraft forced to land because drone operators have congregated around active fires hoping to capture the best photo. In simple terms, a flock of birds happens under different conditions then a “flock” of drones.
So what does it all mean? It means that while there is always a risk of collision, statistically speaking, but the risk to an educated drone operator is very little. Getting the right drone education is important, because you need to learn how to safely fly your drone. Remember, it’s a dangerous tool, not a toy.