back to article Drone collisions with airliners may not be fatal, US study suggests

A ground-breaking US study has shown that while drone collisions do pose a threat to airliners, the odds of a collision causing a crash are much lower than a rival British government study claimed. The American Federal Aviation Administration (FAA)’s drone research divison, Assure, conducted a study into the effects of drones …

  1. Bloodbeastterror

    "may not be fatal"

    And the simple corollary is "may be fatal"...

    1. #define INFINITY -1 Bronze badge

      Re: "may not be fatal"

      I'd love to meet the down-voters. I suspect logic is not their forte.

      1. Bloodbeastterror

        Re: "may not be fatal"

        "I suspect logic is not their forte"

        I suspect vocabulary is not their forté... :-)

        1. #define INFINITY -1 Bronze badge
          Boffin

          Re: "may not be fatal"

          "I suspect vocabulary ... "

          Well yes, that's a simpler way of putting it. And I should've taken the trouble to accent. Did I mention we're off-topic?

          Downvotes to this post are permitted on account of the incorrect icon.

          1. 's water music Silver badge
            Headmaster

            Re: "may not be fatal"

            And I should've taken the trouble to accent.

            ...should *of*...

            1. Duffy Moon

              Re: "may not be fatal"

              "...should *of*..."

              Hahaha. Oh dear, oh dear.

              1. 's water music Silver badge
                Happy

                Re: "may not be fatal"

                Hahaha. Oh dear, oh dear.

                Oh please, you're Oxford comma's are killing me.

      2. Doctor Syntax Silver badge

        Re: "may not be fatal"

        "I suspect logic is not their forte."

        Saying anything cautionary about drones brings out a flock of downvoters.

      3. JDX Gold badge

        Re: "may not be fatal"

        As a passenger being told "you _might_ survive if this happens" is really not great to hear.

    2. EveryTime Silver badge

      Re: "may not be fatal"

      That doesn't necessarily follow.

      Try it in this phrase: "ingesting 250mg of dihydrogen monoxide may not be fatal".

      When something is extraordinarily unlikely, using it in a conversation subtracts from the discussion.

    3. Anonymous Coward
      Anonymous Coward

      Re: "may not be fatal"

      Depending on context, this might be a lot like the statement 'water may not case cancer'.

      Excess caution in statements involving risk, however tiny the risk, distorts logical analysis in too many cases.

  2. Chrissy

    UK Government playing fast and loose with facts?

    http://clearvisionsecurity.co.uk/drone-collision-study/

    1. Little Mouse

      Re: UK Government playing fast and loose with facts?

      The major flaw with the UK study is that they forgot to defrost the drone first...

      1. macjules Silver badge

        Re: UK Government playing fast and loose with facts?

        Fair due to the UK Government that this is actually hysteria from BALPA and not from MAA/CAA, so it is not 'official'.

        For BALPA’s Flight Safety Specialist to suggest that a drone could cause an uncontained engine failure is both reckless and purposefully inflammatory. It’s because of comments such as these that BALPA statements are looked upon with deep skepticism by members of the drone community.

        1. SkippyBing Silver badge

          Re: UK Government playing fast and loose with facts?

          'It’s because of comments such as these that BALPA statements are looked upon with deep skepticism by members of the drone community.'

          Whereas BALPA have no issues with the drone community's comments...

  3. Steve Todd

    250kts assumes

    that the drone will be stationary on collision and allows no safety margin. Probably better simulated at 300kts, and against multiple parts of the air frame and engines.

    I'm not saying that the UK study hasn't over cooked it, but the US version seems a bit on the light side.

    1. SkippyBing Silver badge

      Re: 250kts assumes

      It's also worth remembering in many countries* aircraft under ATC control can exceed the 250kts below 10000' rule, if only because frankly if its speed through the air generating your lift why not have more of it.

      Obviously military aircraft aren't restricted by this at all.

      *Some seem to regard it as a law, others as a rule

      1. Fursty Ferret

        Re: 250kts assumes

        Exceeding 250kts below 10,000ft is a fairly common - some airspace doesn't actually have a speed restriction; other times it's for ATC's benefit; more often it's for us to either lose height quicker or make up time. Most well-built aircraft will happily descend at 340kts.

        Some common sense required, obviously.

      2. Omgwtfbbqtime Silver badge

        "...*Some seem to regard it as a law, others as a rule..."

        More of a guideline really...

    2. druck Silver badge

      Re: 250kts assumes

      Glancing at a flight radar sight, there are half a dozen aircraft over the south east of England right now doing more than 250kts below 10,000ft. Most are around 280kts, so 300kts would be a better test.

    3. 404 Silver badge
      Joke

      Re: 250kts assumes

      What if British Chinese drones carried the coconut payload on a line?

      Since American Chinese drones are non-migratory ...

    4. Orv Silver badge

      Re: 250kts assumes

      While the speed restriction under 10,000 feet is 250 knots, bird-strike testing on windshields is done at 350, so there is some margin for error here. Most drones top out around 40 mph anyway, in the same range as avian cruising speeds.

  4. Anonymous Coward
    Anonymous Coward

    Chicken cannon

    Computer simulations carried out by Assure found that a 1.2kg quadcopter striking the windscreen of a commercial jet airliner travelling at 250 knots simply bounced off, leaving a few marks or chips on the windscreen.

    Computer simulations are all well and nice - but they are no substitute for an actual experiment. Luckily, the subject has been extensively studied - aircraft hitting slowly-moving, flying objects in a few-kilogram range is not exactly new. The experimental technique used is quite cool - it is a chicken cannon.

    An impact by a three-pound chicken could do a lot of damage to an aircraft windshield - although it is not supposed to shatter it (this is part of airworthiness certification tests) - so the Assure's simulations are likely correct for this type of impact. Ingestion of the same chicken by an engine could easily lead to catastrophic consequences - even if the engine is not destroyed, it may shut down, leaving the aircraft without power during a critical phase of the flight.

    As a frequent flyer, I could do without large chunks of metal hanging in the air in the flight path, thank you very much.

    1. Anonymous Coward
      Anonymous Coward

      Re: Chicken cannon/ This:

      "even if the engine is not destroyed, it may shut down, leaving the aircraft without power during a critical phase of the flight".

      Well, that's bloody inconvenient. If the other engine(s) fail then the passengers could be stuck at 30k feet all bloody night!!!

      Personally, I blame Isaac Newton. If he hadn't discovered gravity then the aircraft would just have floated gently back to earth. But no, he had to stick his bloody oar in and now because of his discovery, we'd all be doomed to plummet earthwards.

      Haven't we learned, some things we should just leave well alone.

      1. This post has been deleted by its author

      2. Adam 1 Silver badge

        Re: Chicken cannon/ This:

        > If he hadn't discovered gravity then the aircraft would just have floated gently back to earth

        Speak for yourself. Down under, the prospect of such a failure means that your aircraft slowly drifts into deep space.

    2. Chrissy

      Re: Chicken cannon

      Did you not read the article?....

      "

      Computer simulations carried out by Assure found that a 1.2kg quadcopter striking the windscreen of a commercial jet airliner travelling at 250 knots simply bounced off, leaving a few marks or chips on the windscreen.

      "

      and:

      "

      The computer simulations of the collisions themselves were validated by dropping the real-world drones from various heights, with the resulting smashes filmed on high-speed cameras and compared to simulator predictions. Researchers found a high match between simulated damage and actual damage.

      "

      ... so where's your evidence to support your assertion thus:

      "

      An impact by a three-pound chicken could do a lot of damage to an aircraft windshield - although it is not supposed to shatter it

      "

      ??

      1. ravenviz

        Re: Chicken cannon

        no substitute for an actual experiment

        Um, yes it is. By definition.

      2. SkippyBing Silver badge

        Re: Chicken cannon

        'The computer simulations of the collisions themselves were validated by dropping the real-world drones from various heights, with the resulting smashes filmed on high-speed cameras and compared to simulator predictions.'

        I'm not convinced this is as effective a verification of the simulation as firing the drones at representative speed from a cannon. By rough calculation* I make it an 850m free fall to hit 250kts (463kph), which I suspect they didn't do. So they could only realistically be verifying the low speed simulations.

        *i.e. ignoring drag and whatever the terminal velocity of the drone is.

        1. JDX Gold badge

          Re: Chicken cannon

          You don't have to test at 250kt to correlate simulation against real life. If your simulations against lower speeds bear up well to real life, you extrapolate the same holds at conditions you are unable to test easily. This is rather the point of simulation... anything other than "fly a laden passenger jet into a load of drones" is by some measure a simulation.

          1. SkippyBing Silver badge

            Re: Chicken cannon

            'You don't have to test at 250kt to correlate simulation against real life.'

            I'd agree you don't have to, but for something like this I'd rather they could interpolate rather than extrapolate for new simulation points. As the Qinetiq report allows you to. If they'd realise the full version.

        2. anonymous boring coward Silver badge

          Re: Chicken cannon

          " By rough calculation* I make it an 850m free fall to hit 250kts (463kph)"

          That would be a very impressive vacuum chamber!

          Terminal Velocity in a 1 bar atmosphere for a drone is probably not very high.

    3. Version 1.0 Silver badge

      Re: Chicken cannon

      The last time I had anything to do with this they were firing the chickens into the engine at full thrust - a successful test spat out chicken curry (or a close approximation) at the other end. The average aircraft is in far more danger from Li batteries in the hold than drones.

  5. My Alter Ego

    "May not be fatal"

    I'm pretty sure they will be to the drone. Won't somebody please think of the drones

    1. Anonymous Coward
      Anonymous Coward

      Re: "May not be fatal"

      We could start a new game, warring, laser tag fighting drones.

      Now, for a title, Hmm, lets see.....

      Ahh, got it. Game Of *Drones..

      Hey, HBO, how do you like those apples???

      Comedic effect only. (Insert quad, hexa, octo COPTERS as required but stop calling them drones!)

  6. Chairman of the Bored Silver badge

    How is this different than birdstrike?

    If I hit a 2kilo bird or 2kilo drone at the same relative velocity, do I really care? There are more birds at present. Large birds can cause issues - esp when they go into engine cores - as demonstrated by the American that landed in the Hudson River.

    For some slightly sensational reporting of CFD results, see: https://vtnews.vt.edu/articles/2015/10/102815-engineering-jetenginedronestrike.html

    1. Anthonyl

      Re: How is this different than birdstrike?

      All birds should be refused a licence to fly near aircraft and drone owners should only be allowed after training. Happier now?

      1. Chris G Silver badge

        Re: How is this different than birdstrike?

        Anthonyl, "All birds should be refused a licence to fly near aircraft and drone owners should only be allowed after training. "

        Why, if drone owners are to be required to undergo training, should birds be exempted from training?

        Clearly, given the relative frequency of birds flying wherever they want without any form of formal training or indeed any form of licencing, it should be considered both urgent and necessary to introduce compulsory training for all birds and to refuse them access to airspace without the relevant course attendance and licence.

        As an aside; can a 3Kg chicken, frozen or otherwise actually acheive sufficient altitude to be any kind of threat to airliners? Including when they are taxiing.

        1. 's water music Silver badge
          Coat

          Re: How is this different than birdstrike?

          As an aside; can a 3Kg chicken, frozen or otherwise actually acheive sufficient altitude to be any kind of threat to airliners? Including when they are taxiing.

          I know they aren't noted for great flying and have short legs, but taxis? My mate keeps chickens and I would want a cleaning deposit up front before letting one of them into my cab.

      2. Orv Silver badge

        Re: How is this different than birdstrike?

        All birds should be refused a licence to fly near aircraft...

        At least until ATC has assigned them squawk codes.

    2. Bronek Kozicki Silver badge

      Re: How is this different than birdstrike?

      A drone is not made of meat, bones and feathers. It is made of aluminium, carbon fibre and steel bits. Also lithium ion batteries, which are known to be flammable. The study confirmed that, upon strike, the battery is more likely to disintegrate than burn, but it is useful to know it. Would be also good to know what happens to the engines if they get stuffed with this type of materials, rather than a bird.

      1. Chairman of the Bored Silver badge

        Re: How is this different than birdstrike?

        Very good points. In my experience though I don't think the materials hardness at these velocities makes much difference. KE is KE. The total energy content of the LiIon is dwarfed by the kinetic energy of the rotating machinery , even assuming it has time to deflagrate before ceasing to exist. The design basis for an engine is to "survive" ingesting one of its own fan blades, which poses much more interesting materials challenges to downstream equipment than bones or metal and plastic bits. Survive here means to continue producing thrust for some time period, not experiencing "uncontained" failures etc.

        Consider the American Airlines' Hudson River incident: both engines ingested multiple large geese - far beyond design basis - and both shut down with severe internal damage. But the passengers did not have hot bits of metal penetrating the cabin, severing control lines, etc. Their bad day could have really sucked but some quality engineering really paid off. Sometomes you do get an uncontained failure - a Quantas A380 incident comes to mind - but these are pretty rare.

        For the US the relevant law is FAR 33, which I think the Chinese leverage. Do not know what Europeans use for certification. See:

        https://www.law.cornell.edu/cfr/text/14/part-33

        For specifics.

        1. SkippyBing Silver badge

          Re: How is this different than birdstrike?

          'Survive here means to continue producing thrust for some time period, not experiencing "uncontained" failures etc.'

          I don't think continuing to produce thrust is on the cards, the imbalance from the missing blade alone would mean shutting the engine down before it shook itself apart. The EASA regulation would have the same number as the FAA one but I can't remember what the equivalent of FAR is.

          1. Anonymous Coward
            Anonymous Coward

            Re: How is this different than birdstrike?

            On the other hand, every modern aircraft with more than one engine is designed to fly with an engine out... and unlike birds, drones don't seem to form co-ordinated flocks.

            1. HausWolf

              Re: How is this different than birdstrike?

              yet

          2. Chairman of the Bored Silver badge

            Re: How is this different than birdstrike?

            See FAR 33.76 and the associated advisory circular. For small to midsize birds you need to demonstrate 75pct thrust for 2min regardless of internal damage. For large flocking birds? You're flocked.

            Good example of decent thrust after severe fan damage is the British Midlands crash; due to human factors crew shut down their good engine and flew a pretty good

            distance (~30min) on a destroyed one, though not at full power. IIRC this was a fan failure with parts ingested... the works. Too low and slow to relight perfectly good engine they had shut down when loss of performance became apparent. Dead engine failed totally on throttle up and a/c did not make runway.

        2. anonymous boring coward Silver badge

          Re: How is this different than birdstrike?

          "The design basis for an engine is to "survive" ingesting one of its own fan blades, which poses much more interesting materials challenges to downstream equipment than bones or metal and plastic bits."

          And yet a few geese knocked out both engines on that Hudson plane.

          If a drone could knock out several blades, which then, obviously, get ingested, we have a situation.

          I guess the actual result would depend on what bits the drone contains, and where they happen to hit the blades. Perhaps the drone is carrying a camera, with a titanium mount and some other metals.

      2. JohnMurray

        Re: How is this different than birdstrike?

        https://vimeo.com/144401420

    3. Mark 85 Silver badge

      Re: How is this different than birdstrike?

      Bird are a different problem than drones from what's been published. While a dead chicken may or may not destroy an engine, a frozen bird will. As I recall there was a major cockup at one test where the birds were still frozen. Given such goodies in drones a batteries, this might be something for the testers to think about. Or maybe actually test on an old engine....

      1. Nick Ryan Silver badge
        Coat

        Re: How is this different than birdstrike?

        So you're suggesting that we should be firing frozen drones at the planes?

      2. Orv Silver badge

        Re: How is this different than birdstrike?

        As I recall there was a major cockup at one test where the birds were still frozen.

        I hate to be "that guy," but this is an urban myth.

        1. Francis Boyle Silver badge

          Re: How is this different than birdstrike?

          And I hate to be that other guy but it is also Mythbusted.

        2. Alan Brown Silver badge

          Re: How is this different than birdstrike?

          "I hate to be "that guy," but this is an urban myth. "

          On the other hand, UK and USA locomotive front windows have had to be armoured against CONCRETE BLOCKS for decades, after a number of "unfortunate incidents" involving things deliberately dropped from overpasses.

          1. John Brown (no body) Silver badge

            Re: How is this different than birdstrike?

            "On the other hand, UK and USA locomotive front windows have had to be armoured against CONCRETE BLOCKS for decades, "

            Luckily, locomotives are not required to fly, so don't have the same sort of weight restrictions. (apart from the occasional MagLev, but that's not really flying as such.)

            1. Orv Silver badge

              Re: How is this different than birdstrike?

              Luckily, locomotives are not required to fly, so don't have the same sort of weight restrictions.

              In fact locomotives are frequently built heavier than necessary, in order to improve traction. The coefficient of friction between steel wheels and steel rails isn't great, and traction ("adhesion," in rail parlance) is often much more of a limiting factor than horsepower. All they can really do to improve this is add wheels, which has its own limitations, or add weight. Some yard switchers are actually ballasted with concrete.

  7. Anonymous Coward
    Anonymous Coward

    Possible US study flaws?

    The El Reg description of the US study doesn't make any statement about validation of their windscreen models. Civil aircraft windscreens are complex beasts. This is far more important than getting the drone model exactly right, and why we don't have to fire live birds at windscreens during tests.

  8. phuzz Silver badge
    Boffin

    It would have been nice if the author picked one set of units (preferably SI or elReg) and stuck to them throughout the piece.

    Especially as the FAA publication seems to have given every quantity in SI (and Imperial in brackets).

    1. Anonymous Coward
      Anonymous Coward

      "the FAA publication seems to have given every quantity in SI (and Imperial in brackets)."

      Did they get the conversions right? There have been documented incidents where incorrect conversions have led to incidents and casualties.

      In the UK, as more people pass through the education system with no experience of pre-SI units, this is going to get interesting. A couple of years back I was randomly helping a relatively new graduate review an aircraft safety document. One of the dimensions was quoted in both metric and dinosaur. The conversion was clearly (to me) wrong. The employee in question had no exposure to legacy units and didn't think to check that kind of thing in a document which had allegedly already been reviewed by experienced people.

      1. Orv Silver badge

        Oh, aviation is especially fun. It's mostly in "dinosaur" units in the US -- speeds in knots, altitude in feet -- but older aircraft sometimes have airspeed indicators calibrated in *statute* miles per hour, and distances can be given in either. Vertical speeds are sometimes given in fpm, sometimes in knots -- although in that case the conversion is at least simple (1 knot = 100 fpm).

  9. Steve Davies 3 Silver badge

    But did they test for....

    454gr of C4 attached to the Drone when it gets sucked into the engines?

    Sorry but anything man made getting into the way of an Aircraft is not going to end nicely.

    IT is bad enough with birds. I witnessed a bird strike take out an aircraft just as it took off. Not something you forget in a hurry.

    1. Chairman of the Bored Silver badge

      Re: But did they test for....

      Wouldn't a proper British drone use PE-4 instead of American C4? Seriously though most military HE will just burn if ingested. Its shock sensitive, and usually does OK with bullet impact. Dont think rotating machinery poses a big problem.

      Now, a proper missile warhead with a slapper, booster, and HE charge... with a frag casing to make the little expelled bits more exciting... THAT is a problem. Ask the poor people on the Malaysian air flight that got whacked over Ukraine... what a hell of a way to go.

      1. Spanners Silver badge
        Paris Hilton

        Re: But did they test for....

        I remember my training on that. It burned very hot and metled. If it did that more than a few metres above the ground, it would either all be burnt up before it hit the ground or would hit the ground in microscopic pellets.

        The engine it had just gone through might make more of a mark though...

        Getting such a device through an engine is a non-starter though. BUK missliles contain much more than 454 or 908g of explosive and have a honking big rocket at one end and a serious targetting system at the other. The biggest and best civilian drone that the government hopes will "go away" is insignificant in comparison.

    2. Chrissy

      Re: But did they test for....

      "I witnessed a bird strike take out an aircraft just as it took off. Not something you forget in a hurry."...

      ... yet you forgot to mention when and where this incident took place, what aircraft was involved and how many fatalities it caused.

      Unless it was when you were watching "Sully"?

      1. Steve Davies 3 Silver badge

        Re: Bird Strike

        The one I witnessed was in late 1977 at Dunsfold Aerodrome.

        An HS125 was taking off with some Chinese VIP's on board. It flew into a flock of birds at about 20ft above the ground. Both engines flamed out. The pilot got the gear up and bellyflopped.

        The plane went over the A281 and took the top off a passing car. The driver and passengers was the wife and children (plus others) of a pilot who was in the control tower at the time.

        Everyone on the plane escaped with minor injuries at most.

        https://aviation-safety.net/database/record.php?id=19751120-1

        I was working there at the time.

        Is that good enough for you?

        1. Chrissy

          Re: Bird Strike

          Perfect... explained, and with links too.

        2. Doctor Syntax Silver badge

          Re: Bird Strike

          And those were only lapwings!

    3. Anonymous Coward
      Anonymous Coward

      Re: But did they test for....

      Given how hard it is to hit an aircraft with a carefully designed multi-million dollar fourth generation surface to air guided missile, drones are not really a credible threat.

      1. MachDiamond Silver badge

        Re: But did they test for....

        "Given how hard it is to hit an aircraft with a carefully designed multi-million dollar fourth generation surface to air guided missile, drones are not really a credible threat."

        Military aircraft can be hard to hit since they are fat on sensors to detect incoming missiles and can maneuver out of the way. Passenger flights lumber along in a straight line and are highly unlikely to have missile detection gear.

        Drones flown in the takeoff and landing lanes of an airport have a very good chance of hitting an aircraft if the pilot is trying to get close for pictures. They don't have a very good 3D awareness of where their craft is and the difference between getting close and getting smashed isn't all that large.

    4. CrazyOldCatMan Silver badge

      Re: But did they test for....

      454gr of C4 attached to the Drone when it gets sucked into the engines

      Will most likely result in 454g of C4 in minced form being ejected out the back of the engine..

  10. verno

    What About...

    "The Assure simulations assessed what would happen if either type of drone smashed into the wing leading edges, windscreens, tail fin leading edge or tailplane (horizontal stabiliser) leading edges of the aircraft."

    Any reason they didn't modal a hit to an engine?

    Matt

    1. rmason Silver badge

      Re: What About...

      As above.

      I came here to wonder why they (seemingly) haven't bothered to model them being sucked into the engine?

      We are all aware that a sack of bones covered in feathers can do damage, so how about random bits of metal, platic and carbon fibre with a li-po pack thrown in for good measure?

      The study seems to say:

      "You might not die if an aircraft is by a drone here, here or here (with the relevant steward gestures)"

      1. SkippyBing Silver badge

        Re: What About...

        The advantage with engines is that airliners have to demonstrate the ability to fly with one of them inoperative to be certified for use. Consequently although a drone strike on an engine would probably lead to it failing that's not a problem for the aircraft.

        1. verno

          Re: What About...

          Might cause a bit of a problem if the other one(s) was already knackered though...

          (admittedly so would a bird strike)

          Matt

          1. Orv Silver badge

            Re: What About...

            Fortunately drones don't usually fly in flocks, unlike birds, so the odds of multiple strikes are probably low.

            Not to say it couldn't cause an accident -- there are a disturbing number of accidents where an otherwise survivable engine failure turned deadly when the crew shut down the good engine instead -- but it's in principle recoverable.

      2. gazthejourno (Written by Reg staff)

        Re: Re: What About...

        Mea culpa - while trawling through the 700-odd pages of supremely detailed research into the other areas, I completely missed the next volume (!) setting out the engine research. Refresh the article and take a look at the update at the end.

  11. Anonymous Coward
    Anonymous Coward

    How can this be?

    In this environment where every near miss with an alleged drone (i.e. airborne Tesco bag in most cases) must be reported as if we were right on the verge of a major air disaster, trumpeted by clickbaity doom-laden headlines, and correspondingly hand-wavy, overwrought writing. How can it possibly be that a tiny little lightweight machine might bounce right off a big heavy machine, leaving little trace but a couple of chips on the paintwork? Who'd a thunk it?

    1. Anonymous Coward
      Anonymous Coward

      Re: How can this be?

      They're like UFO sightings. [Almost] everyone sitting on a plane has a camera, with a lot of them looking out of the window. Why are there no pictures of drones near planes?

      1. anonymous boring coward Silver badge

        Re: How can this be?

        "Why are there no pictures of drones near planes?"

        Because you would be passing them at 250mph+, perhaps?

    2. Anonymous Coward
      Anonymous Coward

      Re: How can this be?

      "How can it possibly be that a tiny little lightweight machine might bounce right off a big heavy machine, leaving little trace but a couple of chips on the paintwork?"

      Birdstrikes do bring down aircraft, occaisionally. Drone impacts are still not fully understood. Fancy that...

      1. DJO Silver badge

        Re: How can this be?

        OK so a dronestrike probably won't kill everybody on board, hurrah. Of course the drone owner/operator will personally pay for any damage such as a £5 million engine rebuild.

        Even minor damage to an airframe or engine will result in the craft or engine being removed from service while checks and repairs are made - this is very expensive and drone operators should be 100% liable for any damage caused. This itself is enough of a reason to avoid flying drones anywhere near flight corridors.

        1. Yet Another Anonymous coward Silver badge

          Re: How can this be?

          A bit of metal sucked into an engine at take-off can destroy a concorde

          No litter bins should be allowed within 5km of any airport / helipad / hospital

          1. Alan Brown Silver badge

            Re: How can this be?

            "A bit of metal sucked into an engine at take-off can destroy a concorde"

            It wasn't sucked into the engine. It punctured a tyre, which exploded and sent shards into the bottom of the wing, which happened to also be the unprotected fuel tank. From there fuel poured out and got ignited by the engines.

            The reason concordski (TI-144) was grounded was precisely because of this vulnerability. The soviets realised the risk pretty quickly due to the more remote strips not being able to guarantee cleanliness and couldn't figure how to mitigate it without making the aircraft too heavy to fly economically when it was uneconomic in the first place.

            Interestingly, the vulnerability of the wing tanks was already known thanks to at least one ground incident: Concorde dumped thousands of litres of fuel all over the apron at Harewood airport (Christchurch NZ) in the late 1980s whilst parked up, when someone managed to whack the underside of the wing with a too-tall ladder. There is videotape of the fire crews attempting to stem the leak in the TVNZ archives.

          2. anothercynic Silver badge

            Re: How can this be?

            Except that's not what killed Concorde. What killed Concorde was a titanium strip that ruptured one of Concorde's *tyres* which exploded, and the fragment of which subsequently penetrated a wing fuel tank and then caused a fuel tank leak. The engines being at full reheat were involved but only peripherally. They ignited the escaping fuel. *THAT* is what killed Concorde.

        2. Anonymous Coward
          Anonymous Coward

          Re: How can this be?

          "Even minor damage to an airframe or engine will result in the craft or engine being removed from service while checks and repairs are made - this is very expensive and drone operators should be 100% liable for any damage caused."

          Good point well made.

          The same principle of recovering the costs doesn't readily apply to bird strikes, which is one of several reasons why busy airports often invest in systems (people, recorded noises, live predators of the feathered kind, etc) to reduce the risk of bird striike. Prevention is much better than the alternative.

          1. DJO Silver badge

            Re: How can this be?

            The same principle of recovering the costs doesn't readily apply to bird strikes

            Classed as an "act of God" but strangely if you try to claim compensation from his (self declared) representatives on Earth such as the Pope, they sort tell you to go away and have sex with yourself.

      2. Alan Brown Silver badge

        Re: How can this be?

        "Birdstrikes do bring down aircraft, occaisionally."

        Sure, but usually only large birds going into the engines.

        windscreens aren't flat on to the airflow for obvious reasons. This has obvious advantages for impact vectors.

        Don't bother bringing up GA aircraft. The screens are on those are enough to keep the wind out and that's it. The best you can hope for is that the prop macerates the thing before it gets to you.

    3. anonymous boring coward Silver badge

      Re: How can this be?

      "How can it possibly be that a tiny little lightweight machine might bounce right off a big heavy machine, leaving little trace but a couple of chips on the paintwork? Who'd a thunk it?"

      You don't really know what you are talking about, do you?

  12. Milton Silver badge

    Stating the obvious, much?

    Ok, the British study was an incompetent politically motivated exercise (imagine our surprise) but it makes sense to conduct some realistic experiments, just as has been done in the past with the "chicken cannon"—which ISTR once caused a lot of damage with an un-defrosted fowl?

    But I don't think we're going to learn much that common sense couldn't have told us. Yes, most impacts by small drones will be unlikely to bring an airliner down. Given we've seen 737s, 747s and others make successful landings with some big bloody holes in them, even with half the undercarriage torn away, on a couple of occasions with major damage to the control surfaces, we know that modern western airliners can take a fair bit of punishment. A drone is unlikely to hit a plane at 37,000 feet where sheer speed might magnify damage.

    The real question is, what's the realistic likelihood of a worst case scenario? That would seem to be a drone being inhaled by the turbofan of a twinjet at MTOW just as or before it leaves the ground. Given that either Terrorist Bastard or a foolish amateur photographer might be responsible for such a calamity, it is worth considering. In the scenario I've described the plane should be able to continue its climbout, albeit at a reduced rate, and safely return later for landing after using up some fuel—IF the engine suffers only a contained failure, without explosion or fire or other collateral damage (e.g. to control surfaces, fuel lines, hydraulic pipes etc).

    Given turbofan engines are tested literally to destruction (usually by blowing a fan blade clean off at full power in a static ground test), we can *hope* that five or six pounds of Li-Ion battery and a mess of wires and cameras will not cause an uncontained failure ... but this is surely the likeliest and riskiest scenario, so this is the one I would have expected to see tested. It would be an expensive test, so it should be done once and correctly. (IMHO I'd like to see AAIB plan and supervise it, not those clowns at Qinetiq.)

    And of course it still doesn't insulate us against malice: An ordinary drone bearing three and half pounds of the hardback set of "Fifty Shades of Utter Crap" might not cause an uncontained failure ... what about our evil friend, Terrorist Bastard, if he puts a couple of kilos of tungsten shrapnel in, instead?

    1. SkippyBing Silver badge

      Re: Stating the obvious, much?

      I think the biggest risk is actually a strike on the cockpit rather than an engine, this will probably take out one of the pilots and put the other one into a state of shock.

      Re the engine test, it's not beyond the wit of man to make this part of the certification process in which case engine manufacturers will have to demonstrate it before they can sell the engine. I mean they won't be enthusiastic about it but they already have to write one off for the blade ingestion test so it's not like they aren't used to the idea.

      1. graeme leggett

        Re: Stating the obvious, much?

        My thought exactly. A computer simulation of a windscreen strike only covers the physics of the structure not the psychological effect.

        I'm not saying it'll be as disruptive as Solo shooting one of Vader's wingmen in the death star trench but I would be happier if pilots were not distracted when deeply involved in flying aircraft during take off and landing.

        1. Phil O'Sophical Silver badge

          Re: Stating the obvious, much?

          only covers the physics of the structure not the psychological effect.

          Surely not as disturbing as BA5390, where the first office still managed to land despite the pilot having been sucked halfway out of the cockpit: https://en.wikipedia.org/wiki/British_Airways_Flight_5390

    2. Aitor 1 Silver badge

      Re: Stating the obvious, much?

      While I agree with you on principle, I don't think that being forbidden to fly near airports we are going to see flocks of drones, so at worst a single engine would be affected.

      Now, if the drone is big enough to hit both engines at the same time, I would call that a full size aircraft.

    3. Alan Brown Silver badge

      Re: Stating the obvious, much?

      "we can *hope* that five or six pounds of Li-Ion battery and a mess of wires and cameras will not cause an uncontained failure"

      That is a fucking _big_ drone. Big enough to show up on radar and start causing all sorts of shit to start happening if seen around airports.

      If Airbus and Boeing haven't done so already, simulators need to cover birds/drones/plastic bags on the approach path which _aren't_ impacters and see how observant pilots actually are.

  13. Uffish

    Brit Drones vs American drones

    British drone engineering at its finest.

  14. Peter2 Silver badge

    A ground-breaking US study has shown that while drone collisions do pose a threat to airliners, the odds of a collision causing a crash are much lower than a rival British government study claimed.

    Having just skimmed both, I think that the rival British Government study was actually better and don't see what the department for transport has to answer in way of questions. The report is a lot more nuanced than you've reported it and actually did come up with the same results with this class of UAV.

    https://regmedia.co.uk/2017/07/24/ukgov_drone_aircraft_collision_study.pdf

    Airliner windscreens have a more complex and much tougher construction than those of helicopters. It was found that the airliner windscreens, although substantially damaged, could retain integrity during impacts with drones up to speeds typically flown at during the aircraft landing and later stages of the approach.

    At higher altitudes and speeds, modelling and testing showed that severe damage to the Airliner A windscreen, including complete structural failure of the windscreen, did not occur with the 1.2 kilogram class quadcopter components, but could occur during impacts with the 4 kilogram class quadcopter components. Additionally, during one high speed live test with the Airliner B windscreen, the 3.5 kilogram class fixed wing drone components penetrated the windscreen.

    So, same results as the Assure tests on 1.2kg drones. The UK Government found that you have problems with 3.5kg drones, but goes on to note:-

    An important point that this study confirmed was that the components of drones do not behave in the same way as an equivalent mass bird under similar conditions. In fact, the work showed that some of the lower mass projectiles caused more damage than those with a slightly higher mass. This occurred when the harder and denser components, such as motors and batteries, were more exposed on the particular drone model used during the testing. A simple plastic surround covering a drone motor had a notable effect in lowering the impact forces during component testing.

    So basically, both reports agree that 1.2kg drones aren't much of a threat if they hit the windscreen. The British report (physically) tested bigger and heavier drones than the US did (mostly in software) and came to the conclusion that certain designs of heavier drone can be dangerous to aircraft, and suggests that the drone manufacturers consider design changes to drones, such as the motors being surronded by plastic to absorb the energy of an impact reducing chances of a larger drone going through a windshield.

    Further criticism was levelled at the fact that military research firm Qinetiq, the British study’s author, couldn’t find a way to launch its test drone at the Airbus A320-series windscreen being used as a target for real-world validation of its simulations.

    The report says that they did, but the largest drones they tested in the 4kg range wouldn't fit in the gas cannon equipment they were using. So they trimmed off some bits to make it fit, and then did the tests having noted what they did, and the difference they thought this would make.

    I don't think the British government report is anywhere near as bad as is being reported. It was also mostly done via impact testing, whereas the US report doesn't test anything other than a 1.2kg drone and mostly did that via software with a couple of tests to see if the software model was acceptably correct.

    1. SkippyBing Silver badge

      That's a good summary of the QinetiQ report, a lot of the reporting seems to have missed that the tests were to validate the software rather than to see what a typical drone would do. Having had the chance to see some of the video footage of the live tests vs the computer modelling it was scarily accurate. Now they've validated their modelling the next stage is really to decide what an appropriate test would be confident that the simulation will be accurate enough.

    2. P13DM

      They didn't trim bits off a drone for the UK study, they fired a Nikon P900, strapped to a large LiPo on a set of Flare Wheel arms, arranged like a javellin, it wasn't in any way shape or form a consumer drone, it was a Nikon camera unlike any typical hobby drone payload with mass added to it in the form of dated drone parts.

      The photo of the Nikon bridge camera on the javellin was presented to the media, including the likes of the BBC as being a consumer drone, thereafter the legislation being justified by this testing method is being used to legislate against drones that are primarily lighter than 1.2kg. The popular drones now are the DJI Spark and Mavic, so already since both studies, drones are already arguably safer.

      If you cannot conduct a test correctly with a cannon, that in itself is not justification for constructing a test using any components you can strap together and passing it off as a drone, if you're going to do that, you might as well fire a house brick strapped to quadcopter arms.

      1. Peter2 Silver badge

        Again, you VERY clearly haven't even skimmed the report as your directly contradicting what it says on page 12 in paragraph 4.8 and the picture of the drone as launched on page 13.

        If you have trouble arguing against the tests then i'd suggest starting with the fact that it was a 4kg drone, not a 1.2kg drone rather than materially misrepresenting the tests and the conditions of said tests.

        1. P13DM

          I have read the report so have the DMAE (Drone Manufactures Alliance Europe) and they made the exact same observation, which was as follows:

          “Some of the most alarming findings in DfT’s summary are based on an object that resembles a javelin more than a drone,” Brinkwerth explained. “The study’s authors could not find a way to launch a 4-kilogram drone against an aircraft windscreen, so they mounted two motors, a heavy camera and an oversized battery on nylon arms. This object could never fly, much less encounter an airliner at high altitude. Researchers need access to the full test results to understand whether this is an acceptable shortcut for scientific research.”

          My point which you've not understood, is that the 4kg device was NOT a drone, it wasn't representative of a consumer drone, yet this 4kg device was photographed impacted in a windshield by the report's sponsors who included BALPA, this was their exact caption on the photo presented to the media "shows a larger hobbyist-class drone penetrating an aircraft windscreen."

          So BALPA claimed the photo was of a drone (it's not, it's Nikon P900 which is a large camera with parts attached), they have also used the words hobby-ist class, so whatever way you try and spin it, the entire report has been actively misrepresented by those involved in the commission of the report.

          To use the word hobby-ist on a 4kg "drone" is itself an oxymoron, the majority of hobby users are flying the Mavic and Spark which are sub 1kg.

  15. unwarranted triumphalism

    Should be fatal for the drones' owners. Anyone threatening the safety of an aircraft is a terrorist.

    1. Anonymous Coward
      Anonymous Coward

      What goes up...

      "Anyone threatening the safety of an aircraft is a terrorist."

      There's also the small matter of the people on the ground (or close to it) in the area where the aircraft's remains come down. Might be more of a problem for some airports than others, but in general, deliberately endangering the safety of an aircraft doesn't seem like a bright idea.

      Just ask this chap, who was locked up for using just a torch, never mind a drone:

      https://www.aviationwales.com/18-months-jail-endangering-aircraft/

      1. Yet Another Anonymous coward Silver badge

        Re: What goes up...

        But fortunately the clouds of drones seems to block all the laser pointers that were crashing 100s of plane crashes in the imagination of the Daily Mail last year

    2. Spanners Silver badge
      FAIL

      ¿¿Terrorism??

      No. Terrorism is people who try to change the world by terrorising other people into submission.

      I am sure a few years ago, someone in the USA was nearly charged with terrorism for driving a big scary car too fast down the road where there might be children nearby. That is Ars*holism.

      The people who fly big drones where they might fly into aircraft are ars*holes then. The people who fly little ones there are just twats.

      Save serious words for serious problems. There is a big difference between ISIS and some idiot with a £200 toy.

  16. Mephistro Silver badge

    1.2 Kg only?

    There are professional models far heavier and sturdier than this; think 30Kg, including lots of aluminium, carbon fibre and batteries. I ***hope*** that any drone bigger than the ones from the study will be automatically banned from airports.

    Also airliner_windshield != Light_aircraft_windshield, and airliner_jet_engine != Light_aircraft_propeller.

    If one of the drones in the American study hits a light plane's propeller, there is a good chance that said propeller will get bent or even broken, as the impact with the blade would happen at higher speeds, due to the fast rotation of the blades.

    And re:terrorism: You don't need explosives to cause serious trouble during take off or landing. You only need a plastic bag or a party balloon filled with paint.

    1. Richard 12 Silver badge

      Re: 1.2 Kg only?

      Model aircraft have *always* been banned from flying near airports.

      This goes right back to the invention of airports

  17. This post has been deleted by its author

  18. TheRealRoland
    Coat

    So, as long as the drones are coming in at the windshield of a plane, we're all good; i guess it's just a matter of pilot skills to weave towards the drone, making sure it hits the windshield, and not the engine.

    Got it. (my coat, that is.)

  19. Anonymous Coward
    Anonymous Coward

    Other comparable hazards

    Another risk to aircraft... hailstones.

    A large hailstone can be up to 15 cm in diameter, and they do come in 'flocks'... at altitudes where aircraft can be going faster than 463 kph (250 knots).

    Yet they do not commonly bring aircraft down, despite being quite a bit harder than a live bird.

    1. SkippyBing Silver badge

      Re: Other comparable hazards

      They do seriously f*** them up though.

      https://airlinegeeks.com/2015/08/11/a-pilot-explains-hail-and-how-it-can-effect-an-aircraft/

    2. Alan Brown Silver badge

      Re: Other comparable hazards

      "Another risk to aircraft... hailstones."

      Yes. And pilots go well around anvil tops if they have any sense. Hailstones launched by them have been encountered 15-20 miles away from the originating cloud.

  20. Anonymous Coward
    Anonymous Coward

    No useful drones

    Does anyone else find it interesting that the apparently arbitrary mass limit just happens to restrict almost any drone that could actually be useful, rather than a toy?

  21. Chris G Silver badge

    Think Falconry

    It is well known that falconers flying large raptors are a good way of keeping the chance of bird strikes down at airports.

    Perhaps as a parallel, airports could employ teams of large scary blokes with necklaces made of mangled drones to scare away errant drone operators or alternatively, take a leaf out of the book of a farmer I used to know who had problems with dogs worrying his sheep. He shot the dogs and hung the bodies on a gate. Drones or operators? The choice is yours.

    1. CrazyOldCatMan Silver badge

      Re: Think Falconry

      It is well known that falconers flying large raptors are a good way of keeping the chance of bird strikes down at airports.

      Assuming that they don't stick to a regular schedule..

      (We use falcons to keep birds away from some of our buildings. The pidgeons (especially) seem to learn the days and stay away if the visits are on a regular schedule. And are quite happy to be roosting all over the buildings on days that they know the falcon won't be present. So we had to start an irregular schedule. After a couple of weeks, the pidgeons started staying away most of the time.)

      1. anonymous boring coward Silver badge

        Re: Think Falconry

        "And are quite happy to be roosting all over the buildings on days that they know the falcon won't be present. So we had to start an irregular schedule"

        That's amazing! Pigeons having some kind of concept of week days!

  22. Alan Brown Silver badge

    Bear in mind

    That the number of "drone sightings" around Heathrow and other UK airports has increased with a directly inverse relationship to the decrease in the number of "bird sightings"

    And that at least one of those "drones" turned out to be a plastic bag.

    The reality is that when you're on finals, you're concentrating on putting the aircraft on the ground. Birdstrikes (quite hefty ones) on the nose or windscreen are usually never seen until they're smeared all over the windscreen or have already put a large dent in the radome. There are a few gopro videos containing birdstrikes and I challenge anyone watching any of the civil airliner ones to see more than a couple of frames of the winged wonder before impact.

    Personal experience at 70mph in a trainer climbing out at 500 feet is that you won't even see a flight of ducks until one gets macerated in the prop (thankfully it passed just over the the prop, but I never saw the one that left a dent in the leading edge of the right wing)

    On that basis I'll challenge _anyone_ who claims to see a drone travelling at 200 knots around heathrow (lots of nice corner reflectors to bounceback radar signals) and can ID the model, or says they saw it for more than a fraction of a second to start stumping up evidence - and bear in mind that a drone large enough to be easily seen on inbound approach or powerful enough to keep up with an airliner on finals is going to stick out on the radar like a set of dogs balls.

  23. Marketing Hack Silver badge
    Coat

    “Either the FAA have endangered the safety of commercial airliners"

    The FAA--DARE to fly the open skies of America!!

    (Icon shows author of this post donning his white silk scarf and leather coat prior to catching the San Francisco to LA shuttle.)

  24. NBCanuck

    Responsibility/Liability

    Ok....so the actual damage might not be enough to kill everyone on board, but my thoughts are (and benefiting from comments already stated by others here):

    1 ) even minor damage to an aircraft is expensive. (parts/labour/time not in service)

    2) any know damage to the aircraft may result in the diversion of the aircraft to another airport causing additional cost and delays (missed meetings, lost vacation time)

    I don't think the enjoyment of someone playing** with a drone should even closely compare with the rights of the airlines and passengers, and they certainly don't have the assets or carry liability insurance to compensate for all of the losses. People have the right to do a lot of things, and they also are held accountable/liable when their actions cause a loss to someone else.

    Today's aircraft are a lot safer and have some redundancies for things that can go wrong....but that being said, I wouldn't want to be the one to test them.

    *** - I say "playing" referring to amateurs. I separate them out from professional drone pilots who tend to operation a little more cautiously, responsibly, and carry appropriate liability insurance.

  25. Anonymous Coward
    Anonymous Coward

    Of course everyone with an RC airplane (ie. "Drone") has been doing their best to crash into an airplane for the last 40 years or so but only now in the last few years has it been possible for any one to walk into Maplin and buy one that with zero skill or training will go right up to exactly where that person wants it to go and sit there for as long as the battery lasts. Let's not kid ourselves that any legislation will stop a criminal or terrorist from doing what they want with a drone as they do with cars and full sized aircraft.

  26. DougS Silver badge

    Duck duck goose

    Bird strike has been known to take down airliners. I guess these drones are 1) lighter than a goose and 2) fragment for immediately energy release more readily.

  27. martinusher Silver badge

    Isn't it nice when people replace conjecture with facts?

    What this study tells us is what we've pretty much suspected from Day One -- a airliner colliding with a quadcopter is unlikely to bring down the plane but its still not desirable because it causes damage that takes time and money to fix.

    Planes have to be designed to survive impacts with birds. In the vast majority of cases the damage caused doesn't cause the plane to become unflyable; this isn't a matter of luck, its a matter of design. We cannot pass laws restricting where birds fly so we have to learn to live with them. We can regulate where quadcopters are flown but this study says we don't have to go overboard about regulating them.

  28. Bob Dole (tm)
    Trollface

    "Science" huh?

    Underpinning that bill is the “science” of the DfT drone study.

    So what you are saying is that a governmental body twisted science in such a way as to alarm the public so that laws could be changed targeting a specific group of people? The only thing missing would be to claim that 97% of scientists agree with the claim.

    Nah, that could never happen..

  29. JohnMurray

    http://www.popularmechanics.com/flight/drones/a24467/drone-plane-collision/

  30. Kev99 Bronze badge

    BOVINE EXCREMENT! A hit by any object at 500+ MPH can penetrate the body or destroy the blades in the compressors. There's a good chance that a drone, being made of metal & plastic, could pentrate the forward windscreen of a plane. Drones won't squish like a duck or chicken.

    1. Triumphantape

      Ummm yeah... cept planes aren't doing 500mph when they are low enough to be hit by a drone, in addition planes are designed to take hits from large balls of hail which are as hard as or harder than most components on a drone.

  31. Triumphantape

    No duh?

    Look at the average DJI quadcopter and then take a look at the average goose, which planes are designed to survive impact worth.

    https://www.youtube.com/watch?v=_jfXX7qppbc

  32. anonymous boring coward Silver badge

    Of course they "may not be fatal". But unfortunately, they also "may be fatal".

  33. MachDiamond Silver badge

    A little light

    1.2kg is on the low side of drone weights these days. A larger drone carrying a real camera is going to weigh more and hit harder.

    It's not just about an engine being able to survive ingesting a drone or the windshield ONLY getting a nick in it. When I happens, it means that the aircraft needs to be pulled out of service and inspected to be sure there hasn't been any damage that requires repair. For an engine, that can be a major task. If the aircraft was scheduled to be turned around in an hour to travel to the next city, there could be a few hundred people that will be scrambling to find another flight or a hotel room and missing any intended connections. That's tens of thousand of Pounds in costs from one little shite playing in traffic.

    1. P13DM

      Re: A little light - in fact it's not

      That's not on the low side for drones these days, even many professional drone users are dumping larger rigs, going to the Inspire, Phantom and Mavic.

      The Mavic is the go-to drone for consumers (sub 1kg) and so is the cheaper Spark (even lighter still). The latest ArduPilot drone, the Skyviper is under 250 grams.

      Remember, the purpose of the testing is to assess the risk from consumers as licensed operators would be operating within the law.

  34. Silverfox.Mike

    Given we can't even get our house in order regarding personal electric transport such as the Segway or Trikke Pon-E, I'm not surprised how backwards thinking UK Gov is in respect of drone technology.

  35. anonymous boring coward Silver badge

    Of course it "may not be fatal".

    But it also "may be fatal".

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