Are drones really any threat to aircraft when we consider the weights of common birds?

[MS Coast]

I was a passenger on a 737 that inhaled a seagull into the starboard engine on takeoff. There was a very loud bang and the pilots declared an emergency and returned to the field after the fire trucks and such were deployed. My seat was adjacent to that engine intake and I was grateful that the bird didn't cause turbine blades to disintegrate and come through the fuselage wall. I'm not sure the result would have been the same if a drone and its battery had entered the engine.

The notion that a drone can't cause damage to an manned aircraft is an absolute delusion.

 

[spamgnome]

We tend to think of drones as Mavics as that's what we on this forum fly most frequently. But let's not forget that there are other drones out there, still under 55 lbs, that are substantially heavier. Think Inspire. Think Matrice...

 

[sar104]

I was a passenger on a 737 that inhaled a seagull into the starboard engine on takeoff. There was a very loud bang and the pilots declared an emergency and returned to the field after the fire trucks and such were deployed. My seat was adjacent to that engine intake and I was grateful that the bird didn't cause turbine blades to disintegrate and come through the fuselage wall. I'm not sure the result would have been the same if a drone and its battery had entered the engine.

The notion that a drone can't cause damage to an manned aircraft is an absolute delusion.

A large part of the problem, as is evident from the OP, is that without any understanding of basic physics and materials' science, people focus on just the mass of the object and miss the huge effect that the material properties have on the force generated during the impact. That plus the silly "we don't ban birds, so why should we restrict drones?" argument.

 

[sar104]

We tend to think of drones as Mavics as that's what we on this forum fly most frequently. But let's not forget that there are other drones out there, still under 55 lbs, that are substantially heavier. Think Inspire. Think Matrice...

True, but the vast majority of pilots flying those larger drones are better trained and inherently more cautious, due to the costs involved.

 

[Ty Pilot]

Somehow, I missed the previous discussions of this subject, so I found this exchange interesting.

This might be because this topic is sort of the 'back door' to the I-can-operate-safely-BVLOS discussions that are started quite often. Those that fly BVLOS, and think they know they can do it safely without the proper training, tools, and expertise, will inevitably be faced with their biggest hurdle; avoiding manned aviation with no situational awareness. The arguments range from 'what are the odds' to this particular one - even if a drone hits a manned aircraft - will it really matter?

The videos and testimony in this thread alone should suspend any disbelief that a drone actually can do severe damage to a GA aircraft, yet somehow these threads keep coming so I am sure there will be more.

 

[JMC3]

try running a drone in your blender vs a chicken? There are idiots out there that step over the line every day as a pilot of small aircraft It angers me that some people need to play chicken. Or do a three mile test flight or fly over the clouds.
I know of pilots that hit birds and one bird in particular hit the propeller and broke off a blade.

 

[Cymruflyer]

For the non pilots out there, you have to understand that an aircraft can pick up a small rock just taxiing which can put a nick into the metal prop. That nick could start a hairline crack that can propagate into the metal with a potential for a detachment, at some future point.

Birds, as has been explain, are soft with hollow bones and birds do bring down aircraft from time to time. A small aircraft's windscreen is made of plastic and a bird can penetrate it and a drone could do the same, much easier than a bird.

Many people think of a drone strike just hitting the nose or leading edge of a wing but remember, the tail plane is much smaller and more fragile, and a drone could miss all the stuff up front and smash into the tailplane. Just think about a speed of 35mph, what would you rather have shot into your face, a small bird or your drone and that's just at 35MPH?

Birds are rather good of getting out of the way, I've had several close calls over the years, as long as they see you, they do their best to avoid you. No drone ever does that.

 

[MS Coast]

A large part of the problem, as is evident from the OP, is that without any understanding of basic physics and materials' science, people focus on just the mass of the object and miss the huge effect that the material properties have on the force generated during the impact. That plus the silly "we don't ban birds, so why should we restrict drones?" argument.

I like @JMC3's chicken and drone in a blender example. Perhaps this in-home demonstration would further help those folks to understand that mass is not the only issue in a collision

1. Lie face-up on the floor.
2. Have someone drop a one-pound sofa cushion on your forehead from shoulder height.
3. Have someone drop a one-pound can of pork & beans on your forehead from shoulder height.
4. Repeat as required.

 

[snowghost]

On the other hand it is such an important issue that it needs to get aired, somewhat regularly, if only for the benefit of new pilots. Maybe a sticky thread on the subject, with some of the definitive data and references that have been posted previously?

I thought the P2 collision test was very informative. And yes not only are birds mostly water, but they have hollow bones.

 

[Cymruflyer]

I thought the P2 collision test was very informative. And yes not only are birds mostly water, but they have hollow bones.

That's already been stated.

 

[Clintoops]

I'm a fixed wing pilot as well with 6000+ hours spread between small, single engine aircraft and corporate jets. I have experienced multiple bird strikes over the years, and for the most part, the result has only been a bit of a mess on the leading edge of the wing. Birds tend to be soft and malleable, and like humans, they are mostly water, so they just splatter when they hit. Even a prop strike with a bird is typically no big issue.

A UAV would be another issue all together. A direct strike to the leading edge of the wing would very likely end in damage, and although maybe not enough to cause an uncontrolled crash, that damage could become larger during continued flight as a result of the breach caused by the UAV - even a very small one - due to high speed air passing over and through it. A UAV strike to a prop could be a very big issue. A sharp nic to a prop could cause the blade to separate in the area of the strike due to the immense weight exerted on the prop due to rotational forces - which I'm told are many thousands of pounds at RPM. This is one reason pilots carefully check prop leading edges for nics. Even a small one can turn into a fatigue failure in flight.

Lastly, there is the pilot shock factor of a plane hitting anything, be it a bird or UAV. Pilots have enough to think about, and although bird strikes are unavoidable in certain circumstances, responsible operation of a UAV can greatly avoid and even completely negate the possibility. Frankly, I'm surprised we are even debating this subject.

You are for getting ultralight aircraft at one time I had a Quick Silver MX. This Air Craft was like mounting lawn chair on an airframe made of sail cloth and tubing a few cables.
Now it I hit anything it was bad news. The same for paraplanes

 

[OkDrone]

Most everything that can be said has been said here in this thread.

Here is the way it is. The FAA wants no issues (collisions) or for that matter anything that could potentially bring a plane, helicopter or for that matter any other flying aircraft into an accident. This means whatever is needed to prevent it from happening a rule is made.

That is why there are some many rules and regulations, do and don'ts, endorsement's, biennials, medicals and any other measures to help insure that aircraft, manned or not do not injure or kill anyone. In the air or on the ground.

The FFA's policy has been to side on the conservative, restrictive and controlled, And goes with the idea that if it can happen, then let's make sure it won't.

 

[bcfd29]

As a safety investigator for a large scheduled air carrier, birds cause a great deal of damage depending on their size and where they make contact with an aircraft. We did locally (at just one airport) probably a half dozen bird strikes in December, and at least two impacted turbine blades requiring extensive examinations of engine components before the aircraft could be returned to service, and in one case an engine change (bent out of balance blades and ingestion of bird parts into the combustion chamber). The cost for an engine (not including lost revenue from the aircraft unable to fly and earn money or the hours of technician time for an engine change) is 21 million dollars for our largest airframe.

We have had them penetrate the radome (nose), impact control surfaces (slats, flaps and trim tabs), crack windshield sections, dislodge antennas, and the list goes on. Some of the local species can be in the twenty pound range (turkey vultures) which are impressive then they get hit.

While modern aircraft are typically able to manage on one engine, it is not an optimal way to operate especially during critical phases of flight (take off and landing).

PLEASE think about risk versus reward, use good judgement, and be careful around whatever aircraft are nearby while your operating your UAV. The regs are there for a reason and in aviation often written in the blood of others. I would be concerned over a 250 gram object striking a critical component of ANY aircraft operating speeds, and you should be too.

 

[Mantrain]

As a safety investigator for a large scheduled air carrier, birds cause a great deal of damage depending on their size and where they make contact with an aircraft. We did locally (at just one airport) probably a half dozen bird strikes in December, and at least two impacted turbine blades requiring extensive examinations of engine components before the aircraft could be returned to service, and in one case an engine change (bent out of balance blades and ingestion of bird parts into the combustion chamber). The cost for an engine (not including lost revenue from the aircraft unable to fly and earn money or the hours of technician time for an engine change) is 21 million dollars for our largest airframe.

We have had them penetrate the radome (nose), impact control surfaces (slats, flaps and trim tabs), crack windshield sections, dislodge antennas, and the list goes on. Some of the local species can be in the twenty pound range (turkey vultures) which are impressive then they get hit.

While modern aircraft are typically able to manage on one engine, it is not an optimal way to operate especially during critical phases of flight (take off and landing).

PLEASE think about risk versus reward, use good judgement, and be careful around whatever aircraft are nearby while your operating your UAV. The regs are there for a reason and in aviation often written in the blood of others. I would be concerned over a 250 gram object striking a critical component of ANY aircraft operating speeds, and you should be too.

Thank you,

So according to your expert knowledge birds are a safety issue for manned aircraft and contrary to what others have posted birds are not merely vacuous bags of fluid that splat into nothingness on impact.

Appreciate your feedback.


One thing though,

by bird strike, are you referring many birds at once? Or are the issues from single offenders as well?

 

[BigAl07]

Thank you,

So according to your expert knowledge birds are a safety issue for manned aircraft and contrary to what others have posted birds are not merely vacuous bags of fluid that splat into nothingness on impact.

Appreciate your feedback.


One thing though,

by bird strike, are you referring many birds at once? Or are the issues from single offenders as well?

You are totally missing the point... let me explain it...

If a bird which is much less dense, hollow bones, lots of tissue and soft organs, does that much damage to an aircraft, what do you think a dense UAS of the same size weight is going to do.

Would you rather be hit in the face with a 2lb bird or a 2lb brick? It's really that simple . . .

 

[old man mavic]

i will try to answer your thread title ,yes in the right circumstances a drone has the potential to severely damage or even bring down another aircraft , and for that reason the 400ft height restriction and the VLOS rule are in place ,

 

[Mantrain]

You are totally missing the point... let me explain it...

If a bird which is much less dense, hollow bones, lots of tissue and soft organs, does that much damage to an aircraft, what do you think a dense UAS of the same size weight is going to do.

Would you rather be hit in the face with a 2lb bird or a 2lb brick? It's really that simple . . .

ok so the conclusion of this is that a drone of relative weight is more of a physical threat than a bird of similar weight. I am not the expert so if that is what the experts say I am not going to argue that. I will say though that DJI drones do appear to be made as sparing as possible and not particularly robust. For example my Mini 2 is very dainty and almost featherlike [until I insert the battery.]

and one more thing, given Newtons 3rd law if DJI drone of similar weight is more of a threat than a bird of similar weight the only way tht could be is if the latter's weight is distributed through more area.

 

[BigAl07]

ok so the conclusion of this is that a drone of relative weight is more of a physical threat than a bird of similar weight. I am not the expert so if that is what the experts say I am not going to argue that. I will say though that DJI drones do appear to be made as sparing as possible and not particularly robust. For example my Mini 2 is very dainty and almost featherlike [until I insert the battery.]

Your last 5 words prove the point....
[until I insert the battery.]

What part of the aircraft (other than the motors) is the most dense? BATTERY!

If you're flying your aircraft and it impacts another aircraft I would pretty much assume it will have the BATTERY INSTALLED!

 

[BigAl07]

@Mantrain did you watch the video linked in this post:

Are drones really any threat to aircraft when we consider the weights of common birds?

I was wondering about this. I fly a few different drones, from the Mini 2 to the Mavic 3. As drone pilots we need to be so cautious regrading manned aircraft which share airspace. My largest drone, the Mavic 3, certainly cannot be discounted as an object that given some rare circumstances...

mavicpilots.com

 

[AZDave]

But I've never considered what it is about drones that might make them more dangerous than similar-sized birds.

Well, fundamentally drones don't compress near as easily as birds do. If you wanted to design a structure that dissipates shock energy from enertial mass you'd be hard pressed to do a whole lot better than a bird.

A drone, on the other hand, not so much.