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Smaller scale SAMs with close range burst capabilities seem like they might avoid all of these issues, but tracking would be critical. Ideally the blast would at worst minorly damage but not crash an airliner and at best leave some small dents in aircraft skin but take down a smaller-scale drone.

If you take your "reasons why not" logic too far, however, you end up asking "how do we take down an enemy jet" which, I mean, the air force has probably figured out by now.

Why are drones more of a threat than large scale model jet aircraft? If we can't really avoid this then at some point we're going to need to react in a more measured way instead of flipping out and shutting down the airport.

I think the important difference is in the case of a drone, you're dealing with the possibility that it's going to get sucked into a jet engine (which by multi-engine standards should still be "safe"). Therefore the solution can't be worse than the problem and firing off missiles (which may fail and not self destruct correctly) or guns is a bit of an over-reaction. In the case of a military SAM engagement, you go into the scenario with the assumption that the aircraft you're shooting down is going to do far more damage than it could if it crashes in an uncontrolled manner so it's ok if a SAM misfires and blows up an apartment or the target crashes into a school building because that's a better outcome than a nuclear weapon being released, a strategic target being struck or another 9/11 happening.

Now, that's not to say that the equation wouldn't change if there was a realistic threat that someone would mount explosives on a drone and deliberately try to bring an airliner down but for once we can be thankful for the nature of reactionary policy; we can get away with being reactionary here.

Edit: to go on a bit of a tangent, I think the best path forward at this point is to have a system that can detect and locate fast moving radio emitters within the perimeter of an airport that don't correspond with an ADS-B target. Such a system might allow you to track the target and attempt to figure out where it came from.

Agreed and monitoring is definitely the first step. Without knowledge you're not really going to be able to use any sort of weaponry anyway. I'm hoping that this ends up getting handled similarly to birds and we don't have to react at the "enemy aircraft" scale of ballistics.

> the possibility that it's going to get sucked into a jet engine

I've often wondered why the turbine intakes don't have some sort of "filter" in front to prevent larger objects from entering? Birds have been a problem forever. Why isn't there a simple solution? Even a grid in front like a common 4"x4" chainlink fence would provide. Is there some reason why they're all just wide open?

Jet engines have unbelievably powerful suction on their intake side. A fence wouldn't stop anything; a bird or drone would just get broken up into smaller pieces as it's sucked through the filter.

Similarly there's no fence that could keep this crab out: https://youtu.be/AMHwri8TtNE

Have a look at videos of jets blowing vans off the runway and you get an idea of how powerful the sucking is. A bird would get sucked through a chainlink fence in front of the engine.

Also you'd be reducing the efficiency of the engine all the time, which would add up over hundreds of trips.

That wouldn't really prevent larger objects from entering, it would just slice them up on entry.

The actual answer is aerodynamics. Having a structure in front of the turbine blades disrupts airflow, creating turbulent flow over the blades which causes the blades to lose efficiency. It's much easier to design the engine to be able to run for a little while after ingesting soft FOD than it is to create a good debris cover that doesn't destroy efficiency.

Russian airbase in Syria is regularly [according to them] attacked by drones

https://www.rt.com/news/415454-drone-attack-syria-turkey/

https://www.cnn.com/videos/world/2018/08/16/drone-attacks-ru...

Russian military jamming equipment is pretty powerful though, and these systems are also supposedly deployed there https://en.wikipedia.org/wiki/Pantsir_missile_system (the key in this case is the 30mm radar guided autocannon).

I think the laser based systems like the ones that US Navy have deployed recently (https://www.cnn.com/2017/07/17/politics/us-navy-drone-laser-...) would be the future here - those military lasers are supposedly using something like adaptive autofocus on the target, so it seems to be pretty easy for such a radar guided system to make sure that only target gets the focus and only when the line-of-sight is clear of anything else.

I think this is an interesting case. The force response here is a bit different than in non-war-zones but it's still a useful anecdote.

Lasers will probably be part of the solution at some point but it's worth noting some of the drawbacks. You need the target to be above the horizon for safety obviously, so that means you need to be fairly close to it in a semi-urban environment which negates some of the nice range advantages. The other big one is any shiny flat parts of the drone could potentially reflect energy back to the ground briefly, resulting in possible eye damage to anyone within line of sight. The laser would likely be infrared so any aluminum, even unpolished, could become an effective reflector. This could be particularly problematic as people tend to instinctively look at things that burst into bright balls of flame...

Drone chasing drone is probably the most realistic, especially if they could use radar similar to a guided missile. You'd want to be able to recover the drone for evidence, so using a missile, while possible, probably isn't the best.

We'll train the falcons to drop Faraday nets on them.

Birdshot has such small energy when falling you hardly feel it. It is more like rain. No way it would damage the skin of an aircraft.

You overestimate the strength of aircraft exteriors. Even minor scratches become important under full stress.

#7 or bird shot would not even scratch the paint if falling under gravity. It is approximately 0.1 gram. If you ever see what it looks like in real life, it is tiny and soft. The only reason it does damage is because the charge gets it going at a fair speed (which is loses very quickly).

Since you seem to have experience here, what do you think the lightest shot that would damage a midsize drone (ie DJI phantom) at a useful range would be?

It depends on the gauge of shot. It also bears mentioning that having metal shards raining down at an airport presents a substantial FOD risk to engines and could also be kicked up by tires and strike the wing and body.

Highly directional EMP or something similar seems like it could work, if it existed and didn’t represent an insane proliferation and terrorism threat... which it would. Nor does it solve the problem of the drone falling out of the sky. Truth be told, nothing is going to reliably mitigate the drone or its wreckage crashing, so any interception should ignore the contribution of the drone itself to the safety environment. If a countermeasure is deployed, it’s going to present a risk to the public.

That being the case, a SAM with a net warhead, some kind of rapidly setting foam, or a load of tangling wires seems like it would be most reliable without having to worry about UXO. You could even try to mitigate falling risk by ensuring the interceptor remains attached to the target, and then deploys a series of parachutes.

Helicopter prop blast can eliminate drones. https://fstoppers.com/drone/event-organisers-use-helicopter-...

Until a rotor strikes the drone and everyone dies in a fiery crash? That was a pretty stupid stunt on both the part of the pilot and the drone operator

I think a wing on a hovering Helicopter can handle drone impact.

Airplane wing vs DJI Phantom Drone: https://www.youtube.com/watch?v=QH0V7kp-xg0

"While the test done is plausible the speed involved in the test is unlikely especially for the type of aircraft involved."

The brick of meat (bird strike simulation) caused approximately the same amount of damage as the drone.

Are "industrial drones" and "100mph+ fixed wing drones" real concerns? I would think idiots with consumer drones are the major concern.

Supposedly the Gatwick drone was a larger, possibly industrial type. I made the point to illustrate the bounds of the problem. It's easy to assume it'll always be quads but it's very likely we'll see a variety of different configurations in the future and any solution should be flexible.

I agree and think OP's comments about industrial drones are probably a bit of overkill. The majority of cases will be some consumer level drone, probably a lower-mid range one because it's nearly guaranteed to be lost.

This was very funny. Thanks

You never answered why it isn't possible to shoot it down?

I thought I covered that in the kinetic section but if you have specific questions I might be able to help? Basically "shooting" something down requires a projectile so you need something that can damage a drone but won't present a risk to aircraft or nearby communities when it falls back to earth and it also can't present a FOD (get thrown by tires/sucked into an engine) risk if it were to land on a runway.

Train birds to chase drones.

.....did you actually read the post?