If you follow the media, politicians, and some advocacy groups, then you might have read collisions with drones are the largest problem facing manned aircraft today.
The fact is modern aircraft, especially airliners, are already built to withstand collisions with another potentially unruly aviator, birds. The question is how well will these aircraft do against small drones.
The answer is no one knows for sure. Engineers suspect, barring a hit at an unlucky spot like the cockpit, commercial aircraft will be rugged enough to survive a collision with a drone. While a bird may be the same general size of a quadcopter, the consistency is not the same. Lithium batteries and carbon fiber are not exactly equivalent to feathers and flesh. Hence the reason more researchers are putting effort into studying drone and civil aircraft collisions.
Between 1990 and 2013, 138,257 (~500 per month) strikes between civil aircraft and wildlife (primarily birds) were reported. Nearly 10% resulted in damage to the aircraft. Aircraft components hit were almost evenly spread across the front of the aircraft. Over 50% of the damage occurred to engines and the wing/rotor blade with only 6% damaging the windscreen. So, serious encounters are unlikely. But, when they do occur, they can be bad. The most famous of recent history was when a U.S. Airways Airbus A320 suffered multiple bird strikes at the same time. The plane struck a gaggle of geese right after takeoff and lost both engines. The aircraft ultimately ditched in the Hudson River, fortunately with no fatalities. It’s the probability of occurrence and potentially catastrophic outcomes that already drive high design standards for aircraft collisions with birds, ice, and other foreign objects.
Jet engines (and propellers) generally dislike any type of objects moving through them while they are rotating. Fortunately, for anything smaller than say a buzzard, the engine will probably chew up the object and spit it out the back. That’s not to say there may be some maintenance upon landing though. If the engine is damaged to the point of total failure, multi-engine aircraft are designed to fly with inoperative engines, even during takeoff and landing. So, as long as the effected engine stays together, the aircraft should be able to land safely.
Single engine aircraft seem to face a larger problem if they lose their sole source of propulsion. They would need to complete a forced landing which may or may not be successful. The larger problem, however, may be the drone coming through the windscreen which is behind the engine the vast majority of propeller driven aircraft. Like that of the large aircraft, any type of cockpit strike could incapacitate the pilot(s).
Helicopters also have engine and cockpit vulnerabilities, but their rotors are the biggest concern. A direct strike on a main rotor will be bad, a strike on the tail rotor could be catastrophic. Without the tail rotor, the pilot cannot counteract the torque from the main rotor which would result in a loss of control. And what’s worrying to many is helicopters and drones share much of the same low altitude airspace. Thus, helicopters are generally considered the most vulnerable to a drone collision.
Fortunately, engines, cockpits, and tail rotors are relatively compact areas with vulnerabilities in specific directions. So, the probability of your drone occupying the same space at the same time is low. This doesn’t lower the chances of your drone damaging someone’s aircraft, but it does lower the chance of a deadly outcome.
Unfortunately, it’s not going to be possible to drive the probability of a collision to zero. Our job as drone operators is to help keep that probability as low as possible. And two of the best ways to do that is aeronautical knowledge and responsible flying.
Have a good flight.