Drones are a danger to manned aircraft, according to new report

What happens when drones and manned aircraft vie for shares of the national airspace?

Anyone you know getting a drone for Christmas? The FAA estimates that up to one million new drones will be entering U.S. airspace after the holidays. Many of the new pilots will be beginners. Among the most pressing concerns is the risk all those buzzing projectiles pose to manned aircraft.

There's more than a little precedent here. A new study released by The Center for the Study of the Drone at Bard College offers a comprehensive examination of incidents involving drones and manned aircraft in the national airspace over the past two years. Using data from the FAA and Department of Interior, the report, "Drone Sightings and Close Encounters: An Analysis," explores 921 incidents in the national airspace from December 2013 to September 2015.

The authors identified 327 close encounters in which drones presented some level of hazard to manned aircraft, 90 of which involved commercial multiengine jets. There were also 594 sightings, incidents in which drones were spotted near or within manned aircraft flight paths but did not pose immediate danger of collision.

The study found that incidents predominantly occurred far above the Federal Aviation Administration's 400-foot ceiling for unmanned aircraft, often within five miles of an airport. In August, the Department of Homeland Security issued a warning after consumer drones flew close to commercial aircraft at John F. Kennedy Airport three days in a row.

If there's a silver lining to all this, it's that more and more drones will come equipped with altitude restrictors and geofencing to enforce no-fly zones around airports. In November, DJI, the largest hobbyist drone manufacturer in the world, added real-time updates to its existing geofencing feature. Now its drones are automatically prevented from entering sensitive airspace above ongoing emergency situations like forest fires, for example.

Still, geofencing restrictions are not universal among drone makers, and because many hobbyists still prefer to build their drones from the ground up or with the aid of a kit, the problem is not likely to be solved with technology alone. The FAA's ruling that hobbyist pilots must register, which was issued earlier this month, may at least reduce incidents caused by ignorance, as registration includes a mandatory education component.

The next year will be an important one for the FAA, which has resisted imposing many strict rules around the use of hobbyist UAVs. If incidents rise sharply as drones increase in popularity, however, it's likely the agency will be forced to revisit its position.