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What Happens When a Drone Hits an Airplane Wing? [video]

102 points| protomyth | 7 years ago |youtube.com | reply

94 comments

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[+] sbradford26|7 years ago|reply
The sheer amount of airplanes in the sky at anytime is incredible. Also designated no fly zones can change and users may be unaware. So to avoid this issue I think we need to do more than just depend on users knowing where they can fly and not.

Drone collides with helicopter in a temporary flight restrictions (TFR) zone: https://arstechnica.com/tech-policy/2017/12/drone-collides-w...

Map of all airplanes currently flying: https://www.flightradar24.com/40.21,-88.24/6

[+] prawn|7 years ago|reply
There is a lot of air up there. I fly drones in Australia (https://serio.com.au/) and it's easy to stay well out of the way of large aircraft (don't launch anywhere near airports, and restrict your maximum altitude) and helicopters (you can hear them from a long way away).

DJI's software enforces a survey with local regulations before you can fly. The default settings are all very restrictive too.

The authority here provides an app that quickly indicates the flight rules in a particular location - airports and approach paths, non-controlled aerodromes, etc. It's quick enough that it's easy to check as part of your setup procedure.

The riskier situations I think are cropdusters (fly very low and launch from rarely used airfields) or sightseeing planes/choppers (operating close to the ground despite launching from a fair distance away). I often fly at this location (https://serio.com.au/media/20180171.jpg) and on weekends there can be vintage sightseeing planes coming down the beach in that bay, definitely below the 120m (400') drone limit.

[+] rootusrootus|7 years ago|reply
That's really an ADS-B map, which is not actually all planes flying, at least not yet. It's especially sparse for small private planes, which are probably the most likely to find themselves tangling with a drone.
[+] PaulKeeble|7 years ago|reply
There are hundreds of bird strikes every year around the world and so far no drone strikes. Admittedly birds are a lot more numerous but I think drone fliers are also a lot more intelligent with where they place themselves to avoid damage.

There is obviously very real potential for danger but so far drones haven't been an actual danger to aviation.

[+] DominikPeters|7 years ago|reply
I enjoyed that the expert's recommendation was not "regulation", but to change drone design so they more easily break apart on impact. More likely to be implemented and does not need enforcement on the consumer level.
[+] annabellish|7 years ago|reply
>More likely to be implemented

In the big guys, sure. "My first drone" bought from some low-end chinese reseller over ebay probably isn't going to do anything which raises costs unless it has to, which is why regulation exists.

Not suggesting regulation at this point is fair - but I suspect this will take the path these things always take. A problem is identified and the industry creating it is given a chance to solve the problem itself. It doesn't, and so a harder tool is needed to enforce it for the safety of everyone. Sometimes it does get solved itself, and that's wonderful, but this particular area isn't good at that.

[+] cco|7 years ago|reply
I would also support drone manufacturers self regulating via GPS deadzones in designated no fly areas.

Nearly all drones of a meaningful size are GPS enabled and could be disabled in range of a no fly zone. Yes it could be spoofed, yes it would require some effort from manufactures, but self inflicted regulation as an industry here could pay dividends if the alternative is ham fisted regulation following a drone/airplane catastrophe.

[+] djsumdog|7 years ago|reply
I feel like that's kinda the wrong route to go; because manufactures shouldn't be encouraged to design things for planned obsolescence.

There has to be a balance, to where the drone is of the same quality, but has safety components that collapse like the engine compartment of a car.

[+] mxuribe|7 years ago|reply
Well, there go my plans to build an adamantium drone! :-p

(I know, i know, adamantium is not real...)

[+] ars|7 years ago|reply
It made a hole and caused internal damage. But would not have taken down the plane.

Recommendation to make drones "frangible", so they break on impact and do not penetrate into the wing.

In comparison a bird crushed the wing surface but did not cause internal damage.

[+] AmVess|7 years ago|reply
The drone penetrated the wing and broke spars. It is very easy for such an impact to also destroy control surface cabling, wiring, or hydraulics which certainly can cause a plane crash.
[+] CPLX|7 years ago|reply
That was enough to take down a plane easily. Wings don't just sit there on the ground like in the video, they support the fuselage of the plane against serious aerodynamic forces.

They are under load, it's like taking out a bunch of columns at the ground floor of a building. Not to mention that wings are full of fuel, as well as the cables or hydraulic lines connected to the control surfaces.

[+] splurge100|7 years ago|reply
Now also imagine the drone hit the windscreen, and not the wing. Or went into the prop / engine. Or hit the tail and damaged the rudder.

The leading edge of the wing is likely the best case scenario. All others probably result in far more serious consequences.

[+] fermienrico|7 years ago|reply
Wings also hold fuel, so it can catch on fire.
[+] pmilla1606|7 years ago|reply
I think 230mph is unrealistic for such tests. A quick google search shows something between 70mph - 100mph on approach [1]. I doubt drones are found at altitudes of aircraft at cruising speed.

I'm not saying that this isn't a concern but can somebody with actual aviation knowledge (I have none) chime in and explain the 230mph figure?

1: http://www.mooneyland.com/how-to-land-a-mooney-properly/

[+] tlb|7 years ago|reply
Landing speed for a loaded 737 can be up to 203 mph [0]. Among general aviation, a Gulfstream 450 landing speed can be up to 186 mph at full weight and high altitude. The drone itself can have some speed opposite to the airplane. 230 mph is only a little conservative.

[0] http://www.b737.org.uk/vspeeds.htm Note that numbers are in knots.

[1] http://www.code7700.com/g450_vref.htm

[+] ejo4041|7 years ago|reply
My brother actually hit a deer on takeoff a few years ago in Charlotte. It was all over the news that day. It did not do as much damage as this drone did. Mostly just dented in the face of the wing which caused fuel to leak out. It was a little closer to the fuselage. That prompted an emergency landing.
[+] bufferoverflow|7 years ago|reply
How does a deer hit the wing? Aren't they rather high? A small plane that's much slower on takeoff/landing than a commercial airliner?
[+] berbec|7 years ago|reply
Delta v for the deer was likely significantly lower. The video says impact increases with square of velocity.
[+] rasz|7 years ago|reply
>It did not do as much damage as this drone did.

probably wasn't shot out of air cannon at 230mph

[+] dsfyu404ed|7 years ago|reply
This is not all that much more than the damage done by a Canadian goose. I guess makes sense. The drone has to fly so it can't be built like a tank.
[+] k_sze|7 years ago|reply
I'm just glad they used gelatin to simulate a bird. As soon as I heard the guy say he wanted to compare the impact of a drone vs the impact of a bird, I was mentally gasping. XD

I wonder if the results would have been different if they moulded the gelatin into a bird shape (it's moulded as a cylinder in the video, if I'm not mistaken) because then the pressure would have been different. Of course it would probably have been harder to fire from the air pressure cannon.

The block of gelatin also didn't seem to have any hard bits embedded inside. Real birds have bones. While small birds' bones aren't particularly tough, I'm pretty sure the beaks of raptors and some nut-eating birds are tough stuff.

[+] PaulKeeble|7 years ago|reply
Initially plane parts (engines, wings, cockpits) were tested against dead birds but nowadays we have so many live strikes every year that in practice we know what the proxy based on gelatin is for a variety of birds.

Gelatin is harder than flesh but softer than bone and the overall effect is that on average it has the same effect as birds because it is more like an average representation. While parts of birds are relatively tough they aren't in sufficient volume or weight to penetrate any more.

That isn't to say a bird strike isn't pretty dangerous because they can be. Jet cockpits get severely damaged by them as do engines and you can see in the video the effect on a wing.

[+] airuser0|7 years ago|reply
It's similar to the question asked here before: "Can a dog kill a man with a cane?". I personally accepted the answer:"Depends on the dog, depends on the man, and depends on the cane".
[+] foxylad|7 years ago|reply
I'm concerned that the test uses a static wing. If you drop a fishing float directly in front of an obstacle in a river, it will be moved with the water around the obstacle, not hitting it.

Air is a lot less dense than water, but my instinct is that unless the drone hit a very narrow sweet spot it would simply be swept around the wing. And even in that sweet spot, there will be a buffer of compressed air that would substantially slow the impact.

Could someone with more knowledge of fluid dynamics comment on the applicability of static tests like this to actual aircraft damage?

[+] grogers|7 years ago|reply
Does a baseball move out of the way of the swinging bat? There might be some small effect, but it's not the dominant one. In this scenario the wing is just a slightly bigger bat, and the drone is a slightly bigger ball. It would of course take a very (un)lucky strike to collide dead on like this, but not that unreasonable. I do hope they test indirect strikes too though.
[+] raquo|7 years ago|reply
Air movement is a rounding error in this test.

Suppose the curvature of the wing's airflow could in fact push the drone 15cm up or down in the time it takes the wing to advance 30cm forward (a tiny fraction of a second). That would require such a high G load exerted on the drone, it would disintegrate even if it didn't hit the airplane.

But of course, the air density and curvature is not nearly enough to affect a drone so dramatically. Mooney M20's wing generates only about 15 pounds of lift (down force) per square foot of the wing at cruise speed.

If instead of the drone we had a feather (small low density item) and the speed was 5 knots then yes, that might have worked.

[+] Splines|7 years ago|reply
I do not have a fluid dynamics background, but my hunch is that at the speeds involved, and the fact that there is a column of air from the cannon already surrounding the projectile, that this makes this simulation close enough.
[+] anfilt|7 years ago|reply
Keep mind water is much more dense than air. Also air is easily compressed compared to liquids.

So the higher density of water means it can transfer more inertia onto objects. Moreover, it has higher drag than air.

[+] mothsonasloth|7 years ago|reply
A year ago I saw someone flying a drone from the top of the Shard building in London. The person was promptly told to land his drone immediately by the security. However the scary thing for me is that the smaller business planes and commercial plane that fly into London city go really close to the Shard on their approach.

So definitely a collision is now a real risk

[+] JoblessWonder|7 years ago|reply
Interesting experiment. Looks like a lot of fun to use that air cannon to blast things at things.

That aircraft doesn't have any de-icing equipment so it is basically just sheet metal where it hit. I'd be curious to see what would happen if it ran into a wing with than just a thin skin.

[+] secabeen|7 years ago|reply
I don't know that much about air dynamics. How likely is it that a drone would strike exactly on the leading edge of a wing, as opposed to passing just over or just under the wing?
[+] drivingmenuts|7 years ago|reply
If the drone somehow misses the wing, no problem. But the question was: what happens if it doesn't miss?

Safety engineering is about what will happen when that thing that's pretty improbable absolutely happens or at a minimum, trying to plan for things that no one really planned for (like low delta-V deer mentioned above).

[+] gist|7 years ago|reply
Also (along the lines of air dynamics) I am wondering about whether an airplane has a force in the direction it is traveling in and if that force does push anything small out of the way.

As a small example if I have a pot in my hand and I move it in the direction of a tissue the tissue will move. So we have a very large airplane wing moving in the direction of a much smaller drone and the test does not simulate that at all.

[+] cde-v|7 years ago|reply
I'm honestly surprised we haven't seen anyone try to take down a plane by flying a drone into an engine on takeoff.
[+] neuralRiot|7 years ago|reply
It turns out, the risk of terrorist attacks are much lower than some agencies want us to believe.
[+] stordoff|7 years ago|reply
I was discussing this with someone a few weeks ago, and swarms of drones (flying in formation) are a concern, and the only thing really stopping it is that no one has tried (as neuralRiot says).

Unfortunately, I don't really know how you would prevent it.

[+] arwhatever|7 years ago|reply
We need to set about reinforcing the leading edges of airplane surfaces. :-)
[+] mrguyorama|7 years ago|reply
I wonder how easy it would be to make drones have a stronger radar signal? It's probably not nice to clutter up the displays of ATC, but it would be I think a more direct solution for controlled airspace
[+] jessaustin|7 years ago|reply
This type of incident seems unlikely to happen by accident.
[+] SteveNuts|7 years ago|reply
Against a commercial airliner you'd pretty much have to be flying right near the runway of the airport, but for a GA Cessna those can be flying pretty much anywhere.

I can easily see how a small plane could accidentally hit a drone.

[+] berti|7 years ago|reply
It would even be really difficult to do on purpose.