The chance of a small consumer drone causing significant damage to an aircraft is very low, according to a study by researchers from George Mason University.
 
The study used data from bird strikes to estimate what would happen if a drone collided with a plane. It showed that only 3% of collisions between aircraft and birds of similar weight to drones caused any damage, and an even smaller number led to injuries to humans, and these were caused by flocks of birds. Drones are usually flown alone and not in masses.
 
The study was made in response to the US Federal Aviation Administration (FAA) ruling that drones weighing more than 250g should be registered.
 
The researchers, however, said that current media headlines regarding drones crowding the skies are sensationalized. In fact, it’s birds that are taking up a lot of airspace.
 
Even over 10 billion birds in the US, collisions between birds and planes have been rare. From the 160,000 bird strikes since 1990, only 14,314 have caused damage to the aircraft. Around 80% of damage incidents involved large birds such as turkey vultures and geese, which are much heavier than domestic drones.
 
Since bird strike reporting is voluntary, there is a large chance that non-damage causing incidents were unreported, making the actual chance of damage much lower.
 
The study calculated that a damaging incident would occur no more than once every 1.87 million hours of 2kg drone flight time. Fatal events would be much rarer. The researchers admitted that birds and drones are made of different materials, and the FAA should conduct studies using actual drones.
 
In conclusion, the researchers deemed drone flight as an “acceptable risk to the airspace." This may be a factor in computation of risk, as some insurers, and at least one drone manufacturer, have offered insurance policies covering unmanned air vehicles.