Drone Denial-of-Service Attack against Gatwick Airport

Someone is flying a drone over Gatwick Airport in order to disrupt service:

Chris Woodroofe, Gatwick’s chief operating officer, said on Thursday afternoon there had been another drone sighting which meant it was impossible to say when the airport would reopen.

He told BBC News: “There are 110,000 passengers due to fly today, and the vast majority of those will see cancellations and disruption. We have had within the last hour another drone sighting so at this stage we are not open and I cannot tell you what time we will open.

“It was on the airport, seen by the police and corroborated. So having seen that drone that close to the runway it was unsafe to reopen.”

The economics of this kind of thing isn’t in our favor. A drone is cheap. Closing an airport for a day is very expensive.

I don’t think we’re going to solve this by jammers, or GPS-enabled drones that won’t fly over restricted areas. I’ve seen some technologies that will safely disable drones in flight, but I’m not optimistic about those in the near term. The best defense is probably punitive penalties for anyone doing something like this — enough to discourage others.

There are a lot of similar security situations, in which the cost to attack is vastly cheaper than 1) the damage caused by the attack, and 2) the cost to defend. I have long believed that this sort of thing represents an existential threat to our society.

EDITED TO ADD (12/23): The airport has deployed some anti-drone technology and reopened.

EDITED TO ADD (1/2): Maybe there was never a drone.

Posted on December 21, 2018 at 6:24 AM119 Comments


AlanS December 21, 2018 6:49 AM

I have long believed that this sort of thing represents an existential threat to our society.

Not that the Brits need a lot of help in this department at the moment. What’s happening at Gatwick is just a preview of what’s going to happen on a much larger scale on March 29th if the government goes through with its own “no deal” denial of service. As others have pointed out, the government has been aware of this threat for years but has been too distracted to give it, as with lots of other important matters, sufficient attention.

JG4 December 21, 2018 7:16 AM

Interestingly enough, the F-86 pilot left the imperial forces over a drone incident in the Korean era. The Huey Pilot foresaw this possibility 35 years ago, in a slightly different guise using radar chaff. I reviewed some of my previous writing as recently as here.


Can’t recall if I posted the UAV links in any of my previous comments on drones.

This is a reasonable description of projected intent:


the projection axes are time and space. the novel vehicle is robotics, although it will be clear that guns project intent too, just on different scales of time and distance than robots

The first trace of the term in my notes is this email from 2009. Some of this traffic went to Bruce, particularly the Doug Casey treatise.

from: JG4
date: Mon, Feb 9, 2009 at 1:12 PM
subject: Re: update, cont’d

Another thing that is going to be really, really big is robotics, especially in agriculture. And some of the next frontiers of the legal system are going to be dealing with projected intent, where the intent is embodied into machines that are sent to do mischief and mayhem. There is no end of “bad” people out there who want to do bad things. I use the quotes to indicate crazy, criminal, and/or motivated by ideology to hurt people without proper cause. As it becomes easier to do crimes with machines, it will become a real problem and inevitably, legislators will overreact and there will be a big legal quagmire. We are seeing the leading edge of projected intent with a variety of computer crimes.

I’ve been meaning to send you an article about why aircraft carriers are sitting ducks – the answer is projected intent, via cruise missiles and torpedoes. I know there are countermeasures, and countercountermeasures, and so on, but the situation is wildly asymmetric with regard to costs.

Doug Casey, of the rabidly libertarian stripe. As noted, not a bad starting point, but you have to manage the idiots, psychotics, criminals and psychopaths, particuarly the ones who run governments.

———- Forwarded message ———-
From: JG4
Date: Fri, Nov 18, 2011 at 4:10 PM
Subject: your brilliant treatise on terror
To: Doug Casey


This is a spectacular read. Congratulations.
[the link is crapped out, but I have a copy handy – it delves into the origins of terrorism from a robustly libertarian perspective]

I’d like to coin the term “projected intent” for systems that do dirty work remotely. They are going to be a major criminal, regulatory and legislative problem.

One leading edge is the FAA’s attempt to ban model airplanes that fly over 60 miles per hour. Any idiot can go to x and buy y that will power a modest UAV to nearly 200 miles per hour. The genie isn’t going back in the bottle as long as advanced electronics and consumer products are available to the general public. Even radio control gliders can get to 400 miles per hour.

See for example:

I suggest that you provide an advance copy of your treatise to the following folks, if/when the subscriber-only period comes to an end. It would be really clever to track the traffic generated from each of their sites by using a different flag in each URLs that you provide. Readers at all of the sites are potential subscribers.

All the Best…JG4

On Thu, Jul 13, 2017 at 9:30 AM, A. Goodfriend wrote:

Interesting, “Projected Intent” is not a concept I am familiar with. I agree with you, full throated liberatarianism is an unstable political equilibrium and quickly turns into either full throated Manchester Liberalism or radical social engineering. Definitely not a fan of either one.

On Tue, Jul 11, 2017 at 11:45 AM, JG4 wrote:

not sure how lucid I’ve been on my retreat from rabid libertarianism (as fine a starting point as anyone in Ireland ever had) to legitimate concern that many genies are coming out of their bottles at the same time.

did I introduce a concept called “projected intent?” I don’t think that this touches it, but the 3D printer revolution and related technologies empower people to do what they want. that isn’t all good all of the time.


My quote which can be extended to a full-length treatise on how the organizing principle of entropy maximization leads to the need for security.

“Diplomacy/collusion/conspiracy/spying/war/technology/etc. is merely the continuation of entropy maximization by other means” – with apologies to von Clausewitz

more succinctly, “Money and power are entropy maximization” I’ll submit the first-principles derivation for review again later.

Bruce Stephens December 21, 2018 7:17 AM

As to the punitive penalties, I presume whoever’s responsible knows they’re in trouble if they’re caught even if they didn’t know of the specific up to 5 year jail term.

Presumably they’re confident they won’t get caught or the risk is worthwhile for some reason.

Amazon December 21, 2018 7:26 AM

@Bruce: “The best defense is probably punitive penalties for anyone doing something like this — enough to discourage others.”

This is a mistake because it should not be difficult to hack a drone as a way to send his owner to prison. Remember it is difficult to prove who actually ordered the drone to drive to the airport.

jbmartin6 December 21, 2018 7:51 AM

This asymmetry of cost is the same lever used by “4th generation warfare” aka guerilla warfare

Patrick December 21, 2018 8:01 AM

Give a few years, and fully autonomous drones will be cheap enough to fly these kind of attacks fully unattended. Will make it rather hard to solve it with punitive penalties then (unless one outlaws these kind of drones which probably won‘t stop the really bad guys).

Wael December 21, 2018 8:09 AM

I don’t think we’re going to solve this by jammers, or GPS-enabled drones that won’t fly over restricted areas.

No, we’re not! We’re not gonna solve it — period


This is a mistake because it should not be difficult to hack a drone

Right. Or having some AI / Bot direct and control the drone. Unless we track drones by serial numbers, like we do with “other things” (don’t want to start an x/anti-x discussion, asI have no skin in this game,) then attribution will be debatable. A good defense attorney will get a “red-handed”, “caught with his pants down” “person of interest” out, in no time. Too many plausible deniability holes (Drone went astray, lost control, battery died, or …) A terrorist hijacked my Drone and commandeered it 😉

AlanS December 21, 2018 8:18 AM

The Guardian view on drones: effective regulation needed:

Last year the Department for Transport announced a suite of regulations that would have imposed responsibility on the owners of all but the smallest, toy-type drones. These would require owners to register and sit an exam to prove that they understand the potential dangers of their hobby. But these sensible changes have not made it into law: the government has been preoccupied with other matters.

Today we should also spare a thought for those who died 30 years ago after a security incident involving London’s other major airport.

Doug December 21, 2018 8:40 AM

Forget annoying. If you want a movie plot, just set a couple dozen on the departure end of a runway and launch them at the same time with the intent to hover in the flight path so they are ingested into a few engines. We are gonna need a lot more Sullys.

Paul December 21, 2018 8:41 AM

Am I missing something, Restricted space, trespassing? Can’t it be shot down? When owner cries foul jail him for 10 years and fine them the cost losses for the airport.

Brad December 21, 2018 8:46 AM

There are bird strikes on commercial airliners literally all the time:

Incident: Hawaiian B712 at Hilo on Dec 15th 2018, bird strike
Incident: Precision AT72 at Mwanza on Dec 9th 2018, flock of birds
Incident: Southwest B737 at Sacramento on Dec 6th 2018, bird strike
Incident: United A319 at Dallas on Dec 1st 2018, bird strike
Incident: THY B38M at Istanbul on Nov 28th 2018, bird strike
Incident: Compass E175 at Sacramento on Nov 27th 2018, bird strike
Incident: Eva B773 at San Francisco on Nov 25th 2018, bird strike
Incident: American B38M at Boston on Nov 24th 2018, bird strike
Incident: Comair B738 at Cape Town on Nov 22nd 2018, bird strike
Incident: Southwest B738 at Pittsburgh on Nov 14th 2018, bird strike

(Non-exhaustive list from AVHerald.com)

Its really not clear to me what the actual additional danger to aviation is. Geese can be over 5kg, which is the equivalent of quite a large (and expensive) drone.

I’d argue that having 4 people on the corners of the airport watching for drones and warning the control tower would mitigate most of the risk, and be relatively cheap to implement during a “drone incident”. You’d also get additional intelligence about the direction the drone came in from.

What the last couple of days has demonstrated to bad guys is that if you want to attack an airport you absolutely can with little money and little training and be devastatingly effective.

Also – lots of radio controllers for drones and model aircraft use 2.4GHz – I expect it would be quite hard to track the rogue transmitter in real time, given the ubiquity of wifi and so many transmitters in any built up area.

A couple of other points:
– You can not jam GPS around airports because its used as a primary navigation source for aircraft (and drones)
– You can not jam 2.4Ghz around airports because of the collateral damage to surrounding area’s
– Even if you did jam 2.4Ghz, you could use 3/4/5G mobile data for drone control
– You can have a pre-programmed GPS path for a drone to fly. Some drones today have a “return to launch point” GPS mode if they loose communication to the controller.

Cvnk December 21, 2018 9:47 AM

@Brad I haven’t seen any definitive description of this particular drone but I’ve heard it described as being more substantial than a typical hobbiest drone. Whatever that means.

I was also reading another article that mentioned impact tests done with small (1 kg) drones that suggested the risk can’t be ignored. In particular there is concern about battery packs getting lodged while burning. Also can you assume a drone flying around an airport isn’t carrying additional material designed to maximize damage?

Shooting them down seems like a good idea but you’ll want to do it in a way that doesn’t fire projectiles around the airport or into surrounding areas. Lasers perhaps. Or counter-drones.

Impossibly Stupid December 21, 2018 10:04 AM

The best defense is probably punitive penalties for anyone doing something like this — enough to discourage others.

I’m surprised anyone still thinks this way, let alone you, Bruce. The death penalty has not been effective as a deterrent for much more horrible crimes, so I don’t know what you think would actually work here. And given that actual terrorists are comfortable with suicide attacks, it makes even less sense to think you can best address these problems from a punishment angle.

I have long believed that this sort of thing represents an existential threat to our society.

They’re a threat to short-sighted thinking, yes. In the same way that maybe, just maybe sending in an amped up SWAT team to shoot anything that moves on the basis of an anonymous phone call is a bad idea, maybe it’s just an inherently stupid idea to leap to shutting down airports over minor threats like these. Yes, the problem needs to be addressed, but only to the degree that it represents a true danger. Deal with the reality of the situation, not the misguided TSA/movie plot fantasies you deride others for promoting.

vas pup December 21, 2018 10:30 AM

Laws will not resolve the problem because they are working after (reactively) bad event with minimum deterrent effect for future on determined criminals/terrorists/foreign agents. They are working on good people to stop their bad thoughts to materialize into bad actions.
Only technology/science could provide REAL solutions in ANY security(personal, physical, data, national, etc.) because it is working proactively against source by timely detection of possible threat, affecting source of threat to prevent bad outcome and/or minimize it.
Do you see through the whole history that law/international is violated – even recently how some permanent members of UN Security Council start wars, invasion, annexation, etc.?
Conclusion: I stick to Al Capone quote “With Bible[laws] and a gun [technology] you could get more than with Bible {laws} only.”
Lets leave laws for lawyers and real security for STEM- type folks.

albert December 21, 2018 10:44 AM

“…The best defense is probably punitive penalties for anyone doing something like this — enough to discourage others….”.

No, attribution will still be a problem. Shoot ’em down.

Pound for pound, drones are more dangerous to aircraft than birds.

Regulation? Sure, it can be done, but how effective can it be? It’s certainly not in the league of gun control, is it?

When drones bring down a plane and 100+ people die, then perhaps the gov’t will stop sitting on their hands and do something about it. (I’m talking about the US here, England may be the first to act)

. .. . .. — ….

Wael December 21, 2018 11:15 AM


No, attribution will still be a problem. Shoot ’em down.

Let’s see what that takes:

  • At least one snipper in each airport
  • At least one snipper around the airport to cover landing planes
  • Possibility of snipper shooting the pilot / plane by mistake — friendly fire
  • Decoy drones that divert attention until their big brothers come at the right moment
  • Shooting a drone may not necessarily bring it down immediately


Can’t it be shot down?


@ tlogan,

They need to get the Dutch police to come over with their eagle

Right! Good choice. Let the plane ingest the eagles too. But from what I hear, plane engines are supposed to be able to digest a frozen turkey and still function. Anyhow, I am afraid they’ll need more than one eagle.

What we need is to fight fire with fire. Manufacture Airport police patrol drone swarms that capture rogue drones. AI-driven, of course. A decent laser gun on the plane won’t hurt either.

vas pup December 21, 2018 11:18 AM

@JG4: Thank you for link provided on disruptive technology in warfare.
I would say with those new developments in technology defense should be developed with higher speed than offense.
I guess that future belongs to new less-than-lethal technologies with dual military and police applications. Nostradamus predicted future huge conflicts intrastate and interstate.
You may believe it or not but reality is the best confirmation of such predictions.
As ‘Art of War’ suggested, the best way to win fight is to avoid the fight.
Force your enemy to give up attacks without destroying/humiliating/screwing him. That is the first part for establishing future normal relations. I’d say security not only by strength, but by wisdom as well.
Without proper understanding motives/grievances of other side, taking into consideration her interests, development of wise mechanism of fair conflict resolution (without using violence in order to be respected or heard), reciprocity and yes, compromise, you’ll not addressing the root causes of disruptive behavior of any actor inside or outside.
Any unfair solution could be only temporary conceiving future eruption/escalation of conflict (e.g. WWI and WWII).

humdee December 21, 2018 11:43 AM


Its really not clear to me what the actual additional danger to aviation is. Geese can be over 5kg, which is the equivalent of quite a large (and expensive) drone.

I am well aware of the bird strike angle too but I’ve always assumed that a drone exploding inside a Rolls or a GE would do more damage than a bird ingestion. I don’t know, I haven’t studied the issue closely. if it doesn’t, then what was all the panic about the fabled “shoe bomber”? He certainly didn’t have anything close to 5KG of plastic in that shoe!

vas pup December 21, 2018 11:44 AM

Gatwick disruption: How will police catch the drone menace?


“Drones and their controllers emit radio signals, which the police can capture and analyse.

While Prof Woodward says there is “not much forensic information in the signals”, there are “some identifiers” in them. This lets two drones work next to each other without signal interference – and could let police identify the drone or controller used, if they managed to record them.

It is also possible the drone operator was not at the airport and was controlling the devices over the internet.”

mark December 21, 2018 11:46 AM

I dragged a thought up just yesterday, and on searching for drone gun, got a ton of hits, starting with a sponsored ad. They work by jamming or toasting the receiver on the drone, at which point the drone goes into autopilot, and lands itself.

I’m not sure why they haven’t used that yet, other than really, REALLY wanting to catch the jerks.

JeR December 21, 2018 12:02 PM

  1. Get cheap drone
  2. Program cheap drone to home in on expensive drone
  3. When emergency occurs, launch cheap drone to crash into expensive drone
  4. Profit hardly diminished!

The cost of defence should not be so high and could ssve the lives of Dutch eagles (falcons).

Phaete December 21, 2018 12:19 PM

Just launch a bigger drone with hacking/takeover capabilities (just google for current state of affairs), or use the eagle.
I must admit i was skeptical at first but seeing that bird in action is just marvelous.

Weather December 21, 2018 1:16 PM

Is taken out the drone nesscary, its a social issues with timescale, the airport have been looking at ccm ,but based on life,return,investment, damage they are still looking,
Just let the story culture for ten years, saw on the news ,ten people were interview 9 said they had Christmas present and family, 1 said they went home and rebooked only.

There will always be things like this unless you build the framework.

chris December 21, 2018 1:32 PM

@Brad — I also think it would be less than responsible to shoot down a drone over an airport at least with a rifle or a shotgun using traditional projectiles. Some companies make guns which fire nets.

The security surrounding civil aviation has some really bad defining characteristics. It’s brittle — there was no alternative to the drone “attack” but to re-route traffic and, essentially, close the airport which sent ripples throughout Europe. It’s reactive — apparently no one saw this coming and there was no coherent plan in place for dealing with it. And finally, while it might be more charitable to say it’s “over-reactive” this isn’t really true; airport security reflects the pusillanimity of bureaucrats. Liquids bans, shoe scanning and dosing passengers with ionizing radiation are all examples of precautions which are more damaging than the “threat” itself. Almost every public-facing security precaution is in place “just in case” and when a reasonable person complains about it, the answer is invariably “Well, what would you be saying if we failed to prevent a REAL terrorist attack?!?”

Not that I would like to be on a jet that sucked in a drone, mind you, but surely someone could have predicted this and had a less disruptive plan in place for it.

JohnnyS December 21, 2018 1:53 PM


A more recent Dynamic Soaring record for an RC glider is 505 mph. IIRC someone calculated the acceleration and it was pulling 91G in the turns.


And that’s a “model airplane” there. Certainly not a “toy” in any respect.

For many years the RC model airplane community in USA, Canada and the UK have had a fairly good relationship with regulatory bodies like the FAA in the USA: The community has been organized into clubs, with insurance, rules on how to fly, and codes of conduct. Organizations like the AMA (USA), MAAC (Canada) and the BFMA (UK) have worked hard to make sure that the real model airplane enthusiasts don’t have to suffer massive and onerous regulations.

One reason why this has worked is because until recently, RC model airplanes were not easy to fly: You actually had to know how an airplane flies and you had to learn how to control it properly even just to get it in the air at all. So the only people who flew model airplanes were people who valued the experience, and were willing to commit the effort to be successful and learn from an expert. That leads to a mindset where the model flyer is proud of their skills and respects the sport.

However the new development and massive market penetration of “drones” that effectively fly themselves and can be operated by relatively unskilled users permits people with a lesser mindset to successfully fly these devices: People with less respect for the sport or the community, and who may think it’s fun to commit dangerous pranks, take naughty pictures, disrupt gatherings or even shut down an airport for darker reasons. Basically, *ssholes and worse!

Gatwick may need to review airport security and deploy some sort of primary radar that can pick up drones, as secondary radar can’t do that. Then perhaps the airport defenders can either send out a “counter drone” to crash into the intruder or throw a net at it, or possibly follow it back to it’s owner. If the radar has an appropriate recording capability, it may even be able to record where the intruder was launched, and if appropriate security cameras cover the area around the airport they may be able to track the operator.

tfb December 21, 2018 2:19 PM

The pros & cons of ‘just shooting it down’, as suggested by various people have been fairly heavily discussed. For a start just hitting it is not trivial, and secondly projectiles from rifles are deadly at quite considerable ranges, so what you’re doing is turning an expensive thing with no risk to human life into one where there is risk to human life. We’re willing to shoot aircraft down in wars because the tradeoffs are really different.

The EMP devices some people are suggesting to toast its electronics are probably not things you want to set off near a lot of avionics which may or may not be designed to cope with that.

In general you can’t just do the things you’d do in a war.

john December 21, 2018 2:34 PM

I’m surprised no one has mentioned using a MASER (essentially, the guts of a RADAR) to fry the drone electronics.

wumpus December 21, 2018 2:57 PM

@John My understanding was that normal targeting RADAR has some pretty hefty power delivered to the target (the whole point is to make it a RADAR beacon for the missile to home in on). It isn’t a MASER (any power transferred is wasted: refection is the whole point).

This isn’t typically something anyone really bothers with: military electronics can take it and the effect on the pilot is nothing compared to any stress level having the alarm that says “your life expectancy is now measured in seconds” go off.

So there should be plenty of “off the shelf” long distance electronics fryers available (at military prices, but this is pretty much military/police budgets anyway).

z December 21, 2018 3:29 PM

The reactions to this from the British government are just so typical. I saw interviews with multiple legislators saying they need to introduce age restrictions for drone purchases (despite having no idea who did this much less their age), ban drone operation within an even wider radius of airports (despite this drone already being within the exclusion zone anyway), and generally just “do something”.

I fully expect the usual set of completely useless laws to be enacted shortly.

z December 21, 2018 3:34 PM


I don’t think anyone was suggesting shooting at drones with rifles. For one thing, they’d be very difficult to hit and obviously there would be a danger to the public. A shotgun with #8 birdshot would do the job much better and does very little damage beyond 50 yards.

tz December 21, 2018 5:41 PM

The problem with “punitive penalties” is you also have to either trace the drone back to whomever launched it (and as jammers or whatever get better, the DroneDoS attack will get better. Less or better electronics, fixed wing instead of a copter.

Remember the FAA attempt on having everyone register and get a number and put it on a drone to fly it if it was bigger than a nano drone?

Know your customer rules for drones (will they be obeyed? What about kits or “spare parts”?).

This is not unlike the “encryption escrow” problem.

Alyer Babtu December 21, 2018 5:56 PM

What is the state of drone on drone combat ? Are there reconnaissance hunter pursuer anti-drone drones ? The aerial dogfight enters a new arena. Artillery is not enough.

TomS. December 21, 2018 10:57 PM

Shooting at drones with projectiles, lasers, or other electronic weapons is obviously reckless. Frequency jamming seems equally ill-considered. The only measure that seems reasonable to my layman sensibilities is RF surveillance and targeting the control channel to force unauthorized devices down to a reserved area.

A short search turns up Jonathan Andersson’s presentation of a software defined radio takeover of a drone control channel @ PacSec 2016 [1]. Slides include brief mention of various RC protocols and operating frequencies. Ars Technica [2] story with comments by dragos.

Consider if one had a database of drone control channel traces. Combine that with an airfield-based Electronic Counter Measures pod. Scan relevant frequency bands. If a trace matches, check for whitelisted drone operators, then command device to land in specified recovery area. Add some fuzzing to be able to recognize unknown control protocols.

There is a company mentioned in the Ars article that describes a variety of capabilities to control drones very similar to above thoughts.

E.g. for a database of uniquely identifying radio frequency traces. The US FAA has access to traces of US Navy radars. Sail too close to an airport and cause interference to FAA radars, and the vessel will quickly receive a message.

[1] https://pacsec.jp/pastevents.html
[2] https://arstechnica.com/information-technology/2016/10/drone-hijacker-gives-hackers-complete-control-of-aircraft-in-midflight/

Bruce K. December 21, 2018 11:23 PM

I’m surprised that this has lasted so long with all the high-tech electronics and
weaponry we have today. Has anyone reported on exactly what the issue is that
this has not been resolved?

I’ve been reading about these high powered lasers for ship missile defense for years.
If they are not just fantasy someone better get started on a laser that can home in
with a low power laser and then when the target is acquired slam it with high powered
laser while tracking it.

This attack smacks of something like ISIS or Al-Qaeda, simple, cheap and dastardly.

This is an act of terrorism, so the penalty should be extremely severe including life in
prison or death for any actual damage or death … but the loss of the airport for however
long is a huge cost too.

My ultimate thoughts on this after listening to some lectures by Bruce Schneier are that
this is a human behavior problem intensified by technology. The basic archetype for
societies today is war, and it leads to a lot of unhappy and disenfranchised citizens.
Perhaps this is what the function of institution of religion used to be for, and today we have
mostly gotten rid of it. Society cannot survive without the buy-in of a huge majority, or
on principle everyone, but the to 15% or so are so self-righteous and contemptuous of
anyone below them it is like internal war. The answer could be to work on how to create
sane, healthy, happy and more equal people.

Weather December 22, 2018 12:37 AM

I don’t think the camera points up to detect falcon or if large a microchip program for the task.

Tit for tat

But when did citizens be a target for military,

Some framework needs working out

Wael December 22, 2018 1:53 AM


I don’t think the camera points up to detect falcon

Which camera, and why would it need to detect a falcon?

But when did citizens be a target for military

Since the dawn of history.

Ggffjkhg December 22, 2018 2:19 AM

I can’t seem to get the whole excitement about closing a UK airport. Doesn’t that happen every time it’s raining or foggy weather over there? Go ask the hotels around Heathrow when they are all fully booked with stranded passengers. harhar

Herman December 22, 2018 5:03 AM

If the pilot can see the thing, then a police helicopter can fly over the toy. The downwash will do it in.

de la Boetie December 22, 2018 7:28 AM

Punitive sentences will likely already be available since I’ve no doubt they will use Terrorism legislation (despite its unlikely applicability to this case, it’s routinely used outside its original claimed scope – which was of course politicians lying).

If committed by ardent activists, those sentences may not in fact be as deterrent as you might wish and of course proof may be hard to establish.

@JohnnyS – BMFA. RC planes are in fact harder to fly (as in control the aircraft) than real ones – I’ve done both. With RC, you not only have to control the plane, but re-orient yourself into the plane’s frame of reference, at a distance. But the drones we’re talking about require little flying skill of course, and some are available in fire-and-forget mode (mainly used for highly useful things like survey).

MarkH December 22, 2018 8:18 AM

I’ve seen news reports through the night concerning the arrest of 2 suspects, a middle-aged man and woman.

As usual, the commentariat here has proposed a variety of exotic motivations, actors, and techniques (including some requiring at least a modicum of technical sophistication).

It remains to be seen whether these two are behind the chaos, and if so whether anyone else was involved.

It might prove to be the case that this massive and costly disruption was the work of a pair of malevolent nitwits using cheap off-the-shelf consumer products.

If so, that would underscore Bruce’s point … high-tech has, in general, increased the capacity of individuals of average resources to do great damage.

Perhaps in not many years, machines will be available for “tabletop printing” of DNA sequences for homemade genetically modified organisms. When that day comes, we will look back nostalgically to the times when a lone idiot (or a small grouping of them) could only slaughter a few dozen by gunfire, shut down computerized network equipment, demolish large buildings full of people, or close a major international airport.

Clive Robinson December 22, 2018 11:27 AM

@ All,

Bringing drones down is not such a simple task as many think.

But first off can we please stop going on about the “cruelty to anamals” of the Dutch Police and the use of birds of prey… As a solution to the problem of drones it was looked into for what are effecyively “nuisance use” of toys not larger sport or comercial / industrial drones that weigh between 5-20Kg depending on type and the payload they can carry.

Whilst on the subject of weight please consider just how heavy some industrial drones can be and the fact they can fly up above 300m / 1000ft with little difficulty as long as they stay in range of control signals. Work out wjat the kinetic energy is under 10m/sec/sec (32ft/sec/sec) acceleration is of 20Kg (45lb) from 310m (1000ft)… You will find that it’s about the same as dropping an adult woman 100m… Ask yourself what shape the woman would be in. Now turn it upside down because she is not realy going to look that much different if the drone plumeted down on her head. But you can also work out the energy of a spent 0.5in bullet and discover it’s a tiny fraction of the energy when it’s “gone up and has come down”.

Thus an uncontroled descent of a large industrial drone is something you realy want to avoid as much as possible as it’s scarily dangerous.

As for shotguns and drones, are people seriously thinking about this?

Drones can be extreamly maneuverable especially the smaller drones they are also extremly fast and can fly in unpredictable ways. Whilst shotguns are kinetic weapons that only applies to each individual piece of shot which not only has a high drag coefficient and low mass they also radiate out just like a standard dispersive force at effectively 1/(r^2)… Which quickly makes them ineffective with range, such that at 50m it’s very hit and miss with miss quickly dominating and shot bouncing off…

Worse drones that are doing a denial of service attack on an airport never need fly low enough for shotguns to be effective. They can be at 100-200m above ground and you could fire standard shotgun amunition at them all day long with little effect.

The problem of dealing with drones in a non war zone is what will happen when they become disabled… Until somebody comes up with a guaranteed way to not firstly shoot down the wrong drone. Or secondly dump it on civilians or their property, the chaces of solutions receiving civilian use licencing currently is minimal at best.

Impossibly Stupid December 22, 2018 11:32 AM

@Bruce K.

Has anyone reported on exactly what the issue is that
this has not been resolved?

Idiots have been hired (or elected) by idiots into positions of authority that they are not competent to hold. That’s the real issue that isn’t getting resolved. I see no signs of it being resolved any time soon because, as Dunning-Kruger demonstrated, idiots are seldom willing to admit they’re idiots (I’m the exception :-).

This attack smacks of something like ISIS or Al-Qaeda, simple, cheap and dastardly.

Not really. It smacks more of a disgruntled worker in the aviation industry. Someone with inside knowledge on how to best monkey with the system, and the ability to set up the drones to do it. This is too “smart” to be traditional terrorism.

This is an act of terrorism

No, it isn’t. So far, it’s just someone screwing around. The only “terror” that’s been a result is the response from officials who wet themselves and shut down everything. Again, that is what needs to be resolved. If your talk of prison or death is for those people, I’d agree that we absolutely need to consider that option.

The answer could be to work on how to create
sane, healthy, happy and more equal people.

And yet how often do we talk about solving that problem? You yourself beat the desk to punish people who are driven to anti-social behavior. If you really want things to get better, you need to address the cause(s) of a problem.

albert December 22, 2018 11:45 AM


You underestimate the skill of our military, and the new technology available to combat infantry. All the bullet points you mentioned can be easily overcome, if you think about it.

I don’t know where you got the “frozen turkey” idea, but it’s total BS. A frozen large bird would, like a good sized drone, destroy a jet engine. Jet engines have never been tested with frozen fowl.

Can we agree on using “sniper” instead of “snipper”?

. .. . .. — ….

albert December 22, 2018 12:44 PM

It seems to me that the Gatwick incident was a hobby drone, pieces of which could have, and should have been recovered. I have no information as to the point where the strike occurred.

The takeoff envelope of an aircraft is quite restricted in the horizontal, and less so in the vertical. Both increase as the distance from the takeoff point increases. The speed of the aircraft increases quite quickly as well. Therefore, it behooves the perp to fly the drone manually to try to intercept the aircraft at some point just after takeoff. Maximum damage would occur if an engine was targeted, but much more difficult to achieve. While the perp may be quite a distance away and still be within the required distance for communication, the drone has to get to the intercept point close to the runway. It must either fly there, or placed on the ground close by. Timing is also important. A clever perp will monitor the tower radio channel and wait for the takeoff clearance to the pilot. It’s easy to obtain the time it takes to reach the desired intercept point by simple observation. I’d guess the times for one type of aircraft would be very close. There’s no guarantee of a successful interception, but the ‘shoot-down’ option is useless under these conditions. Believe me, it wouldn’t take the perps very long to figure out all of this.

On a more positive note, modern jet and turbo prop aircraft can take off with one engine, depending on terrain, altitude, and the pilots reaction time.

May you all have a drone-free holiday!
. .. . .. — ….

Wael December 22, 2018 1:43 PM


All the bullet points you mentioned can be easily overcome, if you think about it.

It’s a matter of pracrticality and effectiveness. Theoretically one can get around it: in practice: it ain’t gonna happen.

I don’t know where you got the “frozen turkey” idea, but it’s total BS

From here, chief: I tried to copy the link at the “current time frame”, to save you time. At least in some of these links.

5.5 lb. Bird ingestion test – @ 1:51
Bird strike Jet Engine Test
Bird carcuses ingestion test
Chicken gun test
No birds, here… but related and worth watching: Engine Explosion Test

I am certain I saw a frozen turkey test at some point. Can’t find it now, but I’ll share it if I later find it.

“frozen turkey” idea, but it’s total BS

“Total BS.” isn’t a fair assessment, given the links I shared. Perhaps “exaggeration” is more fair (and acceptable, until I find the turkey link.)

Can we agree on using “sniper” instead of “snipper”?

Yes, of course! I have problems with duble letters, it appears! I always misspell “Holy”, too! Strange, but I’ll pay more atention next time 😉 But to my defense, it should be spelled “snipper” just like “Red Snapper” is spelled. English is not such a logical language!

Clive Robinson December 22, 2018 5:00 PM

@ Wael, Albert,

But to my defense, it should be spelled “snipper” just like “Red Snapper” is spelled. English is not such a logical language!

Nope it’s an incredibly lazy language… However I’ve been told that once many years ago in the US there was a proposal to remove double letters in words but… with the exception of Native American Names (never checked up on the refrence but it stuck in my mind as being almost as good as making Pi easier).

Mind you I’m hopping/hoping I can borrow your excuse (I was going to work in below/bellow but I’ve just woken up and it’s to much effort).

I think you will find that the “frozen turkey gun” is one of those “journalist misunderstandings/mistakes”.

In that testers do in fact purchase frozen foul (chicken or turkeys) of a given weight in bulk… That they then let thaw out individually as and when required for “The cold chicken test” of the FAA.

Mind you there are the xenophobic stores of “You heard how dumb they are in XXX…”. And apocryphal stories of stray cats climbing in the “Chicken Gun” shortly before firing…

Both myth-busters and snopes have looked down the barrel of the Chicken Test gun, and frozen foul.



Mind you read the Snopes article carefully as you will find at the bottom,

    Not everyone fires thawed birds: before switching to fake birds, the U.S. Air Force traditionally launched frozen ones. (Sensitive to the concerns of animal-rights activists, they now fling birds made of clay and plastic at canopies and engines.) The way the Air Force had it figured, if a canopy could survive an impact with a frozen bird, it would certainly live through a chance introduction to one that could still fly under its own power. They further believed cold chickens provided a better simulation of a bird that had tensed to prepare for the impact.

Make of that what you will.

However as Christmas is aproaching…



Though why you’ld want to do it with the whole bird… I’ve put frozen crumbed chicken quaters in a deep fat fryer “with care” using the basket as have many others…

Wael December 22, 2018 5:39 PM

@Clive Robinson, @albert,

Both myth-busters and snopes have looked down the barrel of the Chicken Test gun, and frozen foul.

My goodness! Is that you, YouBlubing now? Or are you a freaking imposter?

aproaching. (sic)

Ok – false flag, a few spelling mistakes. So what made you change your convictions? Perhaps you found a way to watch YouTube™ without Javascript?

Clive Robinson December 22, 2018 6:01 PM

@ vas pup,

With regards Prof Woodward comments of,

    “[there is] not much forensic information in the signals”
    “[there are] some identifiers [in them]. This lets two drones work next to each other without signal interference – and could let police identify the drone or controller used, if they managed to record them.”

The reason there is little forensic information is that the electronics are mainly made of “digital off the shelf components” like Systems on a Chip (SoC) products. Which unfortunately produce near identical signals as they are designed to do. Whilst there are some small “tolerance / slop” issues with the still analog parts the effects of these components need specialised equipment to record with sufficient accuracy to be used as verifiably reliable evidence.

As for the “some identifiers” these are the equivalent of ethernet MAC addresses[1] that are “aledgedly” uniqie or similar in mobile phones, and may once have been. However to reduce manufacturing and remanufacturing costs these are now programable. Thus do not pass the “verifiably reliable evidence” test.

Not that such lack of reliability will stop overly eager psychopathic prosecuters determined for political / career reasons trying it on infront of judges and juries who’s life experiences would not have equiped them to understand and deal with such behaviours and technical background.

[1] As can be found with the history of ICTsec various access control methods relied on MAC addresses long after it was known to be a very bad idea. Likewise with the electronic serial numbers in mobile phones, which can be changed from the handset keypad or with an “industry known” cable adaptor to a USB interface. Such things are just going to get worse with e-SIMs and the like, and please do not get me started on the lack of security with other “serial numbers” and “seeds” where even “signed” is no more reliable than the absent minded behaviour with Secure ID tokens and Certificates supposed expert security companies took to make a few extra pennies profit…

Clive Robinson December 23, 2018 12:57 AM

@ Mark H,

It remains to be seen whether these two are behind the chaos, and if so whether anyone else was involved.

Firstly Gatwick was closed for 36hours and around 50 drone flights were observed. I don’t know about you but people kind of notice when I’ve not slept in 24hours.

Which brings up the question of just how much time a single person would need to spend doing this when you consider recharging of batteries and other logistics, like getting to and from locations to make the flights from and if another report is true assembling and disassembling a four foot drone.

That is a newspaper that is offering a sizable reward reports there is someone who came forward claims to have seen a cyclist with two drones at a road side, one of which was four foot across, which does not sound like a toy drone.

Other newspapers report quotes from the arrested man’s employer and his Ex (with whom he has a child) that apparently give him alibies for times when the drones were flying. His reported occupation is window fitter and he was on site, or was with his Ex seeing his child.

His occupation suggests he drives and has access to a van, so why would he use a pushbike which would involve a whole lot more time to dismantle and reassemble a four foot diameter drone. Whilst it could with care be dismantled enough to be got into cycle paniers or back pack it would take time be fiddly and prone to making mistakes and loosing parts.

The story so far is not hanging together in favour of him being the drone operator.

But… the man arrested apparently is known to have had a small helicopter and racing car as RC devices in the past. Which it’s been reported that he has posted about in the past on his Facebook page.

However others who know the couple say since being with his current partner who apparently dislikes RC and such like, he has given up RC.

What the truth is to any of this I have no idea. What it does leave unanswered is why the Police arrested him and his partner.

All we know publically is the peoples names and that they live a few miles from the airport, and the story of the man’s facebook page.

If we apply Occam’s Razor to that then we end up with “Police searched social media and arrested the person who very loosly fit a profile and proximity…”

Which means either the police are behaving in a cavalier fashion or there is other information we are not aware of.

Unfortunately in the UK there is a history of the Police behaving in a cavalier fashion especially when there is very high political and media attention. In a number of cases they’ve had to release “early suspects” without charge and in some cases official appologies and compensation. In other cases it has turned out worse with failed trials, presenting of false/faux evidence and innocent people dying in jail…

So I’d be quite skeptical about all of this based on past performance. Especially as some “no name” Whitehall insider allegadly informed a different newspaper it was Eco-protestors/warriors less than 24hours before the arrests…

Clive Robinson December 23, 2018 1:37 AM

@ Wael,

My goodness! Is that you, YouBlubing now? Or are you a freaking imposter?

That’s two possabilities, there are however more, which negate both of those…

Two instantly spring to mind,

1) A Google search[1].

2) Somebody else could have “U-Blubbed” for me.

The “somebody else” could have had ninja search skills and done both and sent me the results… I’m sure you could probably think up more possabilities even ruling out time travel 😉

In fact you did,

Perhaps you found a way to watch YouTube™ without Javascript?

I’m told that it’s possible to do so especially if you want to save the likes of music to your hard drive. I’ve never tried it so can not say if it was or is true.

As it turns out I have a couple of friends that do U-Tube and have shown me things they have pulled down like some crazy Russian driving through an airport check in at half past ten at night. Or some “Political adds” for a UK far right organisation that were ment for national broadcast but hit the cutting room floor instead because they were so lame they were actually funny to watch[2].

[1] Mind you, you are the link king to strange and weird, and you’ve said above you’d not found search results…

[2] Imagine if you can two “blond” people where their hair not only looks unwashed, but has a greenish tint to it. A beer-gutted man standing and a blotchy woman sitting on a sofa. You are ment to think they are a happy couple only they both have that “thousand mile stare” that makes them look like they just want to get out alive. Whilst their body language suggests not only are they not happy together they can not stand each other. His job is to stand there and nod sagely whilst she does the talking. Nothing she says sounds believable or even remotely wise, even though she is trying and failing miserably to look both earnest and sincere. All you end up doing because they sound so wooden is look at the screen trying to find their marionette strings, or the ventriloquists arm.

Wael December 23, 2018 3:45 AM

@Clive Robinson,

I’m sure you could probably think up more possabilities …

Yes! I thought of more likely possibilities. By the way, the links don’t work for me.

you are the link king to strange and weird, and you’ve said above you’d not found search results…

I am sure I have seen it. Perhaps long time ago on TV.

Imagine if you can…

I could imagine that too. Teleported pantyhoses. You had a similar story, long time ago that earned you a yellow-card. What’s with you, women, and sofas? lol…

Wesley Parish December 23, 2018 5:08 AM

I’m sure the UK Police will eventually see reason and place 88mm AA around all UK airports to shoot down drones. And birds. And light aircraft that might accidentally wander into the path of a VIP’s executive jet …

What could possibly go wrong?

(On a much more facetious note, I did have the fugitive idea that using low-level radar – radar focused on the flight paths before aircraft enter them and land – and then a highly focused and powerful but extremely quick blast of microwave radiation to damage the electronics to force any such drone down. Mind you, to be successful, such a blast would need to bring down the larger military-sized drones, because you never know when you might need that power. The military are no more trustworthy than anybody else.)

Clive Robinson December 23, 2018 5:09 AM

@ Wael,

By the way, the links don’t work for me.

Proof if every you wanted that your hypothesis was wrong 😉

Mind you, with all your playing around with “invisable chars”, you should have spotted why they did not work at a glance (as should I).

Each link has,


It should be,


Now they should probably work…

Wael December 23, 2018 5:22 AM

@Clive Robinson,

that your hypothesis was wrong 😉

Yea, crossed my mind. Wasn’t sure if it was deliberate or a result of twisted bypassing procedures.

should have spotted why they did not work at a glance

I spotted that, and still didn’t work. I compared what you had posted to what links should look like. Also noticed the ‘m’ for ‘mobile devices e access’. Perhaps I’ll try again after I take an extended nap (I’ll hibernate for 4 or 5 hours.) It’s almost my bedtime.

stine December 23, 2018 7:54 AM

I can’t wait unti someone does this at Hartsfield, or O’Hare, or LAX. On the other hand, what if they hit Honolulu, Kona, and Maui at the same time?

marc b December 23, 2018 10:00 AM

So far, all 50+ drone reports are by amateurs and essentially unconfirmed. In 48 hours the military pros with hires radar and active and passive night vision have not reported anything.

I consider this an UFO scare, started by something getting in a light beam. A plastic bag, a bird, maybe an antenna or whatever.

Just passin' thru December 23, 2018 10:01 AM

EDITED TO ADD (12/23): The airport has deployed some ant-drone technology and reopened.

Indeed! That’s an innovative technology I’d like to see them effectively use.

Faustus December 23, 2018 11:28 AM

@ Bruce

In the link you provide you question the existential threat rhetoric:

Calling terrorism an existential threat is ridiculous in a country where more people die each month in car crashes than died in the 9/11 terrorist attacks.

But now you embrace it for something that so far has had much less impact than terrorism:

There are a lot of similar security situations, in which the cost to attack is vastly cheaper than 1) the damage caused by the attack, and 2) the cost to defend. I have long believed that this sort of thing represents an existential threat to our society.

Drones attacks seem to be a subset of terrorism so I find it hard to reconcile these positions.

I think it is good we track ownership of drones bigger than toy size. People need to be held accountable in a similar way that we hold automobile operators accountable, recognizing the distinction between accidents, negligence, recklessness and homicide.

But we have too many people in prison. People need to be accountable, but I find our Gulag Archipelago to be unjustifiable. It is a unflattering reflection of the American psyche.

albert December 23, 2018 12:20 PM

“…I am certain I saw a frozen turkey test at some point. Can’t find it now, but I’ll share it if I later find it….”

I’ll try to use logic here. What would be the point of using -frozen- birds in a jet engine test? Give me an example of a flying frozen bird in the wild. The whole idea is absurd. Frozen birds are used, after they have been thawed out.

The RR test vid was interesting, but the narrative was wrong*, as pointed out by some of the comments. Fan blades have come loose in flight causing at least one death that I know of. Did you ever notice the red lines painted on military aircraft fuselages, particularly prop-driven ones?

Best not to sit in a line with those fan blades:)

*must have been written by a news copy writer. You know, the ones that write of “gappers delay” on the freeway.
. .. . .. — ….

Clive Robinson December 23, 2018 12:32 PM

@ All,

It would appear that the two people arrested by Sussex Police are, to quote Detective Chief Superintendent Jason Tingley,

    Both people have fully co-operated with our inquiries and I am satisfied that they are no longer suspects in the drone incidents at Gatwick

Importantly he added,

    “It is important to remember that when people are arrested in an effort to make further inquiries it does not mean that they are guilty of an offence and Sussex police would not seek to make their identity public.

So the hunt appears to be still on with various organisations offering rewards for information leading to an arrest.

@ Bruce,

As people have noted legislation is retrospective in application and designed to keep honest people still honest.

As we know certain people will for various reasons commit crimes irrespective of legislation.

However I’m worried that “rewards” will take us back to “Dead or Alive” bounty hunters who historically developed a reputation for “Shot first ask questions never” to collect their pay and walk away.

At the end of the day justice is a reflection of societies mores and morals. Do we realy want to sink to a dystopian level where there is little difference between those tasked with finding criminals and murderous cut throats and bandits? In essence a “psycho with a badge” to hide behind running loose…

Wael December 23, 2018 1:15 PM


I’ll try to use logic here.

Good idea!

What would be the point of using -frozen- birds in a jet engine test?

Ummm, lemme see how I get out of this predicament!

Give me an example of a flying frozen bird in the wild.

albert, albert! Haven’t you read what @Clive Robinson said about my timetravel abilities, right here for your convienince:

I’m sure you could probably think up more possabilities even ruling out time travel 😉 In fact you did,

Back in January, 2017 — that’s about two years ago — I said, and I blockquote:

I’d rather be on a slow train delayed by a cute swan than on an airplane with a Ruppell’s griffon vulture in its engine at cruise altitude, any day of the year.

So, here is your example: a poor Ruppell’s Griffon vulture is happily flying at 37,000 feet, where the temprature is colder than a witch’s … — about <a href=”https://www.engineeringtoolbox.com/standard-atmosphere-d_604.html>-65F. So far so good? The bird gets smacked by a cargo plane, which happens to be carrying liquid nitrogen, […] which kills it and hurls it another 1000 – 3000 feet up. The bird is now dead at an altitude of 40,000 feet, dowsed in some cool liqud. It descends to 20,000ft completely frozen (don’t believe the wiki article — it won’t take a few hours to flash-freeze the bird,) where it gets ingested by another plane’s engine. See, possible! Logical enough for ya? 😉

Oh, the frozen dead bird can be considered “flying” in this state.

albert December 23, 2018 2:22 PM


I flew to India.
Guess I’m lucky to be alive.

It’s certainly possible for a dead bird to be frozen at high altitudes, and be ingested by a jet engine, but it’s highly unlikely. Modern twin-jet airliners can lose an engine and still fly, otherwise they’d never be cleared for trans-ocean flights.

Regarding the original topic. Notwithstanding bird strikes(which seem to be an accepted risk), drones represent a much more serious threat to aviation, which should be considered a unacceptable risk.

. .. . .. — ….

Clive Robinson December 23, 2018 5:43 PM

@ Albert, Wael,

I’ll try to use logic here. What would be the point of using -frozen- birds in a jet engine test?

Because frozen or thawed it makes no significant difference, is sufficient reason to save time.

The argument breaks down to what is the dominant force in the test. The kinetic energy from the birds mass and velocity, the velocity it’s self or what is actually a marginal difference between the raw and frozen state.

Arguably it’s the kinetic energy not the difference between raw and frozen at the velocities used.

To understand this you will have to go back to the use of the atom bomb during WWII. One of the strange things reported was blades of grass driven into solid objects and flesh as though they were nails.

It’s also why flecks of paint in space can punch right through metal plate as though they were high velocity bullets.

AndyS December 24, 2018 3:07 AM

“Sussex Police said there had been 67 reports of drone sightings – having earlier cast doubt on “genuine drone activity”.

Det Ch Supt Jason Tingley said no footage of a drone had been obtained.

And he said there was “always a possibility” the reported sightings of drones were mistaken.”


We have a situation where one of the world’s busiest international airports was knocked out by reports of drone sightings from the public. There were no sightings of drones by the “authorities” and no evidence of any drones. No pictures, no videos nothing.

So we have to entertain the possibility there were no drones at all. Which leaves few explanations:
1) Incompetence of behalf of the authorities.
2) The authorities were complicit in a deliberate act of misinformation designed to close the airport. Don’t forget, the UK could be crashing out of the EU in 3 months with no deal. This means no regulations for inter country flights, custom checks, nothing.

Although this sounds tin hatty, this has all the feel of disaster scenario testing.

Clive Robinson December 24, 2018 3:55 AM

@ gordo, AndyS,

67 sightings but only a “ghost”, would indeed be embarrassing all around.

I know people can see things that are not there under certain weather conditions but from the weather I remember in SE England at the time –mainly overcast, grey and damp– the usuall ones would have be likely.

Birds of prey of which there are several in the area do hover and swoop thus backlit by a grey sky could be mistaken for a drone.

The lack of aircraft over what would be rich feeding territory might easily bring birds of prey in close to the airport thus increasing sightings nearer the airport where people are less likely to recognize a bird of prey in flight.

Likewise childrens balloons that reflect light could be mistaken for a drone.

Also once you have been sensitized to an idea your mind is more likely to jump to a false positive.

Good this have happened to 67 people I don’t know. But the fact that the sightings indicated there were either multiple drones or the drone and operator were moving around a lot does tend to support the idea on one hand and a team of operators on the other.

Is it possible the first sightings of a drone were genuine, that is a drone was for a short time flow by a prankster then the rest followed on, it would be slightly more likely.

Time to put on another bowl of popcorn 😉

tfb December 24, 2018 5:06 AM

@Wael, others.

I know someone who was involved in bird-strike testing (he built one of the early guns to fire birds at engines for tests), and coincidentally was talking to him yesterday, and the frozen-bird story came up.

The story. During some bird-strike testing at an unnamed British company in the 1950s or 1960s, involving firing birds at a cockpit, it was discovered that they had no chickens. An apprentice was dispatched to buy one. It was loaded into the gun & fired at the test article. People stared in horror at the result: the chicken had punched a hole completely through the cockpit. This was a disaster: there was clearly something terrible wrong with the design which would involve millions of pounds and years of delay. Quickly, bits of the destroyed cockpit were collected for analysis. Along with them were found parts of the chicken … which was frozen.

The truth. This never happened. The birds that planes hit are not frozen and only a fool would test with a frozen bird since such a test is valueless: you want the test to represent what happens in real life, not what does not happen. In the story the apprentice does not realise this, but in fact the birds need to be weighed and otherwise checked before the test: there is no chance that this could happen, especially as failing the test involves destroying the test article which is very expensive.

The story is, in fact, an urban legend probably started in the UK aerospace industry in the 1960s. I heard it in the 1970s (when I believed it, being young) and have heard it again since, when I realised it was an urban legend. The person I spoke to yesterday, who worked in the industry in the 50s & 60s said he did not start the story, while suggesting he might have: I think he probably did not but would like to have, but, well. It may have several origins, of course, as it’s a fairly obvious story.

But once again: it did not happen.

JG4 December 24, 2018 6:08 AM

Wishing everyone Happy Holidays and a Very Happy, Healthy and Prosperous New Year. That’s not much of a Christmas rally in the US market futures this morning, possibly a trap-door to 1800 on the S&P.

@Clive and others participating in the frozen bird discussion – The time rate of energy delivery when e.g., a frozen bird encounters a Perspex surface is much higher than the corresponding unfrozen/thawed bird, but as you note, the area under the curve can only be the same, E = 1/2 m v^2 The rise time of the pressure pulse at the point of impact also is much faster. The unfrozen bird has more internal damping, which will absorb some of the energy. The corresponding and likely smaller energy absorption in the frozen bird goes into cracking the crystal structures, of water and bone. Perspex itself is polycrystalline and shatters somewhat like glass when the internal stress exceeds the elastic limit. Not sure what they call polycarbonate on your side of the pond, but it’s Lexan here. I think that the Germans invented it and much of the rest of chemistry. Lexan has much greater toughness and usually fails more gracefully than polymethylmethacrylate. Both fail spectacularly in the presence of acetone. There are more vivid ways to do this demonstration, but this one is compelling:


I assume that someone smarter than I am already made the leap from ocean steading and sea steading to moon steading and mars steading. Those are the closest to a Planet B in your solar system. We’re going to have to make a choice between cleaning up this one, dying out or moving to another.


Rural broadband is about to get $600 million in funding—but there’s a catch New Food Economy

Big Brother Is Watching You Watch

How Google Tracks Your Personal Information Medium. Part two. Disturbing.

Guillotine Watch

A Gift Guide for Billionaires Bloomberg. I know! A new planet!

Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial British Medical Journal. Don’t try this at home!

andys December 24, 2018 8:22 AM

The story just keeps on giving… Now they are saying the “no drone” statement was a “miscommunication”. Hang on, so the Cheif Superintendent of Sussex police was wrong?

“During a conference call between ministers, chaired by Transport Secretary Chris Grayling, it was agreed the 67 drone sightings were legitimate.” WTAF. How could they possibly know they are genuine if there is no evidence?


And furthermore, why has the government invested so much in this story. They could have just left it as it is but it feels to me like they are just digging a deeper hole.

To me, it now seems certain this was an incident created by the government as part of Brexit scenario testing.

Clive Robinson December 24, 2018 8:58 AM

@ andys,

The story just keeps on giving… Now they are saying the “no drone” statement was a “miscommunication”.

The Guardian actually reported what the Detective Chief Superintendant said, and it was the first on his list of possabilities due to lack of coroberating evidence.

To me, it now seems certain this was an incident created by the government as part of Brexit scenario testing.

I don’t know about “creayed by the government” but I can certainly believe they would milk it for all it’s,worth to keep Brexit out of peoples heads…

What I do find a bit suspicious though is this “broken drone” that has usefully turned up. Lets put it this way there is several truck loads of money down the drain on this a lot in Californian and Australia pensions. Nobody wants the liability to fall on them, thus a broken drone is shall we say convenient for quite a few people.

tfb December 24, 2018 10:34 AM

@JG4 & others, concerning bird strikes.

Yes you are quite correct about the rate at which energy is delivered being the critical thing. In particular the thing that matters in these cases is almost never the total kinetic energy, but the peak force or pressure. This is true for canopies, and also turbine blades (usually really fan blades as that’s what the thing hits in a turbofan): if you exceed some force or pressure on a blade, it will fail in some way and bad things will follow.

A good example of this cycle (pushbike) helmets. If you consider a scenario where someone falls onto the road, then just before their head hits the road it has a certain kinetic energy and after the event, with their head resting on the road, it has none. The change in kinetic energy is the same in both cases, but in only one case is the person dead. The helmet does two things: it spreads the force over a larger area of skull thus reducing peak pressure which means the skull is less likely to fail, and it increases the time over which the collision happens which reduces acceleration & hence force & pressure, which helps things both for the skull and the brain.

This is why frozen chickens are not at all comparable with unfrozen ones. It is also why hitting or ingesting a drone is not at all like hitting or ingesting a bird of the same mass: the two events are simply not comparable.

Clive Robinson December 24, 2018 11:00 AM

@ tfb,

it spreads the force over a larger area of skull thus reducing peak pressure

Err not by your definition of peak preasure, it simply spreads the peak preasure over a greater area.

When you fire a rifle approximately on third of the energy becomes the kinetic energy of the bullet by Newtons laws an equal and opposite amount goes into the butt of the rifle, the remaining energy is a mixture of heat and sound.

Thus the peak preasure must be the same for both.

gordo December 24, 2018 11:32 AM

Whether there were actual drones sighted or not, this incident, other than the abundances of caution shown, reveal that the level of preparedness for “the real thing” is utterly lacking.

Anyway, stuff about a world that’s being made. The below quote is about farmers using drones to survey their fence lines…

Autonomous drone vs self-flying drones, what’s the difference?
By Jonathan Feist
October 15, 2018

Now, what should the drone do mid-flight? Every drone I’ve flown has a very small set of parameters that trigger an automated RTH [Return To Home]. I certainly have not flown a drone that can autonomously identify an intruder then alter its flight to both stay safe and to ensure that video of the intruder goes to the right place. Not to mention setting off alarms.

Surveying a fence line is little different. If the farmer has to retrieve the drone, download the footage then watch the footage to see what the fence looks like, they may have just gone out themselves instead. No question flying a drone for this task can be way more efficient than going for a walk, but if you have to watch the footage, why not manually pilot and watch it live.


I imagine that proposals for airport “drone intruder CCTV watch systems” are being written as we speak.

JG4 December 24, 2018 12:29 PM

@Clive – I can only remember one previous opportunity to gently needle you. The energy in the rifle ends up being a tiny fraction of the energy in the bullet. The pressure indeed acts equally and opposite, and the momentum of the bullet and the rifle are equal and opposite after firing, ignoring the modest momentum in the hot gases. The reason for the great asymmetry in energy is that the force acts over a much larger distance on the bullet, generally the full length of the barrel. However, the force only displaces the rifle by the recoil distance, which to first order depends on the mass asymmetry. Because energy is force times distance the asymmetry in mass translates to an asymmetry in energy For a typical rifle like the ’03 Springfield, the muzzle energy would be in the range of 2700 foot-pounds, vs. a recoil energy in the range of 20 foot-pounds. Coincidentally, the fringe of tolerable recoil for the average shooter. Edward Teller’s friend served in the imperial forces during the cold war. They practiced with their ’03 Springfields until the sap boiled out of the stocks. Makes my shoulder hurt just thinking about it. It would hurt a lot more if the recoil energy were equal to the bullet energy.

albert December 24, 2018 12:54 PM

@Clive, @etc.,

There are slo-mo videos of non-frozen bird ingestion tests on turbofan jets. In the side view you can see how the carcass is sliced into sections, which is remarkable considering the leading edge of the blade rounded like the airfoil that it is. The physics is considerably more complex than simple f = ma. How much force does a blade take on the axis of rotation? Not enough to break it. How much force does the blade take in the direction of rotation? Again, not enough to break it. Not only is there the velocity of the bird (i.e., the aircrafts airspeed), but the velocity of the air stream cause by the engine itself. Jet engines are unbelievably powerful air pumps. There is a case of a person sucked into an air intake of a military jet. Mythbusters showed a small car lifted and blown by jet exhaust. In the Engine Explosion Test provided by @Wael, it appears that the test blade(as well as part of the adjacent blade that broke off) is ingested by the engine, which is what you’d expect if it is prevented from exiting via the housing. A blade exiting the the housing need not destroy the engine.

Cheers, @everyone…
. .. . .. — ….

TRX December 24, 2018 12:58 PM

until the sap boiled out of the stocks

Unlikely. Any blanks showing signs of sap would have been discarded, and there were checks made at each step of the machining process where they would have failed inspection.

The ’03 stocks were, however, boiled in oil to make them less likely to warp in service due to humidity changes or rain.

primary source: “US Rifles & Machine Guns” by Colvin and Viall, which has the complete blueprints, machinery, and manufacturing steps for the ’03 Springfield.

Assembled rifles were dipped in Cosmoline if they were to be stored more than a few years or transported by sea. Cosmoline will penetrate into wood and will keep oozing out on warm days for an absurdly long time.

The most likely scenario would be excess oil or Cosmoline seeping out of the stock. As we approach 2019, it’s still a thing with some old military surplus rifles…

TRX December 24, 2018 1:12 PM

As I’ve learned so far:

A) There doesn’t seem to be hard evidence there were any drones in the first place.

B) The authorities arrested some guy who was so provably not guilty they turned him back loose almost immediately.

C) given that real, verified drone strikes have happened many times at other airports and rated nothing more than angry reports, Gatwick chose to make a completely over-the-top freak-out that hosed a notable percentage of air travel in both the UK and Europe.

D) despite a decade of warnings, the airport authorities apparently hadn’t get bothered to implement any practical plan for dealing with drones.

tfb December 24, 2018 1:25 PM

@Clive Robinson

Pressure is force per unit area, so force is pressure times area (really, the integral of pressure over area). Force times time (again: the integral of force with respect to time really) is impulse or the change in momentum for any body in the collision, and is constant in any two collisions with the same initial & final states by conservation of momentum. The helmet does two things: increases the time the collision takes thus reducing the forces involved, and spreads the force over a larger area thus reducing the pressures.

(None of this says anything about peak values in fact: only averages over time or area, but it’s clear from the structure of the things involved that there are not large peaks.)

(In case it’s not clear: I’m a physicist.)

Clive Robinson December 24, 2018 7:55 PM

@ JG4,

The reason for the great asymmetry in energy is that the force acts over a much larger distance on the bullet, generally the full length of the barrel

Sorry no (though barrel length can increase the bullet velocity).

As agreed from Newton’s third law,

    MV = mv

Where MV is the mass velocity of the gun and also the arm/body mass of the shooter depending on how tightly they hold the gun.

And mv is the mass velocity of the bullet as it leaves the barrel.

So lets fill in some figures with a, .44 Remington Magnum.

For mv we have 0.016kg x 360m/s

Which gives 5.76

Lets assume the gun/body mass is 5kg then it’s velocity is 5.76/5 = 1.152m/s

Now as you know Kinetic energy in joules[1] is half the mass times velocity squared or,

    kinetic energy = 0.5 M V^2

So the bullet kinetic energy is 1037, and that of the gun/body is 3.32 so ~300:1 (if it was the whole body mass of a prone shooter, say 50kg then the velocity would be 0.1152, energy 0.332 and the ratio 3126:1 (hence sniper rifles and machine guns tend to be built “heavy” for more than one reason).

The greater the effective gun/body mass the greater this ratio. If you then alow for the area differences of the face of the bullet and the gun butt as @tfb notes the force per unit of area is likewise reduced.

@ ALL,
The point of interest is purely the time difference between the raw fowl comming to rest and a frozen fowl coming to rest and the shape of the curve (under which the areas should be equall).

And from the few pieces of data available (see the end of the Myth busters clip) the time differences are a fraction of a percent, that is they could not measure them with a specialised high speed camera. Thus the Kinetic energy being the same for raw and frozen fowl the energy time distribution is apparently the same.

Which is what I would have expected and said as much above,

    The argument breaks down to what is the dominant force in the test. The kinetic energy from the birds mass and velocity, the velocity it’s self or what is actually a marginal difference between the raw and frozen state.
    Arguably it’s the kinetic energy not the difference between raw and frozen at the velocities used.

@ All,
Any way it’s now Christmas day in the UK and time for bed, so a merry Winter Festival to you all and whilst raw/frozen makes little difference at Chicken Gun velocities, it does in a deep fat fryer. So take care to have a cool bird not a frosty one to pop in in the morning 😉

@ Wael,

Shows how tired I am, as you know viscosity is measured in redwoods and viscosity as a word is derived from the Latin word for mistletoe. The readwood and spruce (xmas tree) being of the same broader family of coniferous evergreen trees, I was trying to think up a little pun linking redwoods with mistletoe to put in my festive message above, but… My brain is creaking due to the harsh mistress, and the best I could think of was “redwoods being what they are to viscum” to follow velocity, it’s to obscure.

As I used to joke in the army at others,”You lot need sprucing up, go get a pull-through with a Christmas tree”, well it looks like it’s my time to get the “Santa’s chief Fairy” treatment… (I have told you that joke have I not?).

[1] Kinetic energy is in Joules in the SI units but traditionally ft/lbs in the US where the formular usually used is,

    ft/lb = (V.V.M)/450240

Where V is in fps and M is in grains (grains like the related barleycorns are realy obscure units of measure these days).

Clive Robinson December 24, 2018 8:00 PM

@ ALL,

With regards the couple who were arrested by Sussex Police and released.

They have given a message to the press saying the feel uterly violated, are receiving medical assistance and are asking that they and their loved ones be left alone to salvage what little they can from what is left of the festive season.

Wael December 24, 2018 9:04 PM

@Clive Robinson,

(I have told you that joke have I not?).

No, I don’t believe you have. Get a good night sleep, then tell it.

Shows how tired I am…

You and me both!

My brain is creaking due to the harsh mistress

I know exactly how you feel. My brain too.

Weather December 24, 2018 11:34 PM

Just throwing a number out, but by temperature the speed of sound in the propellant is 1500 m/sec after 10 cm in the barrel it reached 1000m/s plus the pressure from change in volume drops force by 2000 ,
There’s not much force left and change in velocity is all so smaller.
The barrel length is rifling, and smooth recoil and gas to load the next bullet

tfb December 25, 2018 6:00 AM

Concerning frozen chickens: I think this is stupidly off-topic now, but it’s important to realise that the interesting part of the event will be probably what happens in the first mm or so of the impact. At 200mph that’s within the first 10 microseconds. How long it takes the bird (or the bits of it) to come to rest in the frame of the turbine is not interesting at all. What is interesting is what the peak forces & pressures are locally: if they exceed what a blade can withstand, even for a very short time, then you’re in trouble: the blade will deform or fail and the turbine will then probably destroy itself.

I think this is really something that you need to develop a good intuition for as naive approaches do not work, at all. Really, unless you’re someone involved in this stuff you almost certainly don’t have such an intuition. (I am not such a person, but I know people who are (or were: retired): I don’t have a reliable intuition about it but I’ve been corrected on my faulty intuition often enough to know I don’t.)

OK, I think this is the end of this topic for me, anyway.

Clive Robinson December 25, 2018 6:30 AM

@ Weather,

Just throwing a number out

It’s the reason I picked the .44 Remington magnum, they are used in both pistols with six inch barrels and rifles with either box or revolving magazines so you can look up the diffrences.

If you want to work out the actual physics of what goes on in a gun barrel it’s exactly the same maths as for a piston engine with the barrel being the cylinder and the bullet the piston.

However a little logic will tell you that the effects in the barrel after the bullet has left the breach is a percentage of the overal effect, because the accuracy would be significantly effected by the change in range due to the temprature of the barrel.

But a little sideways thought with “Gas reload” in semiauto rifles will give you an overview to work from. Yes there is still a fair amount of energy in the hot gases, certainly enough to impart enough energy into the gas rod to drive the working parts backwards. But by then the bullet is moving almost as fast as the expanding gas front, thus little of it gets coupled into the bullet at that point.

There are three reasonable reasons for making the barrel longer, the first to ride the gas front but 15-30inches covers to the point where the added energy nolonger overcomes the effects of friction in standard calibers (the bigger the caliber the longer the barrel can be). The second is to gain extra stability in flight for the bullet (again larger caliber improves this). The third to add “usefull mass” which improves the accuracy (as does a rear locking not forward locking bolt). Oh the larger the caliber as a general rule of thumb the longer the accurate range of flight for like for like bullet profiles.

Clive Robinson December 25, 2018 6:54 AM

@ tfb,

At 200mph that’s within the first 10 microseconds. How long it takes the bird (or the bits of it) to come to rest

From the video clip you can see in the Myth Busters setup the bird frozen or raw had come to a halt within 7.5mS and had started on the rebound. The time distance between frozen and raw was to small to tell due to the limitations of the sensor used.

As with peak overpreasure, we don’t have instruments to measure directly due to dampening and resonance in the sensors and supports (which is one reason to go down the MEMS route). Thus until more recent times it had to be done by calculation, but still does for the more interesting things. It’s actually one of the reasons we still have the Chicken Gun, which are eye wateringly expensive tests to run and often unhelpfull in their results.

Clive Robinson December 25, 2018 7:17 AM

@ Wael,

The weather was mild and Santa was busy outside, when the chief fairy came up to him and said,

    Hey Santa have I got a deal for you

Santa resignedly stopped what he was doing and nodded briefly, so the chief fairy carried on,

    I’ve just got us two million christmas trees for fifty cents each, now that is a deal or what?

Santa looks round at the sunshine and early flowers coming into bloom and says,

    It’s Easter what bl@@dy use is two million christmas trees at this time of year?

And before the chief fairy could reply, Santa said,

    Do you know what you can do with your bl@@dy deal?

And that folks is the reason the fairy sits astride the Christmas tree…

Wael December 25, 2018 10:44 AM

@Clive Robinson,

The weather was mild […] And that folks is the reason the fairy sits astride

Moa ha ha ha! Funny!

Q: Does the word “bl@@dy” require masking? It can’t be that bad; it’s not in the same class as some 4-letter words, huh?

Clive Robinson December 25, 2018 1:48 PM

@ Wael,

it’s not in the same class as some 4-letter words, huh?

That’s because it’s a 6-letter word 😉

But no it is a word with real inoffensive meaning, especially if you’ve ever had a minor cut to the head and seen yourself in the mirror,

“With claret aruning down yer face, like it was in a race. To get around yer chin, for the all important win”.

Wael December 25, 2018 2:53 PM

@Clive Robinson,

But no it is a word with real inoffensive meaning

Then it needs no bloody masking. Dah!

“With claret aruning down yer face, like it was in a race. To get around yer chin, for the all important win”

Clever! I see you’re in the mood for some poetry. My brain has been occupied with some other projects, but I’ll work on something offensive. I have in mind something new… something like this, but tailored for the host and the usual suspects here. Whadda ya think? Yellow (or claret) card material?

Martin December 25, 2018 6:45 PM

Noted several news articles the last couple of days indicate there may have not been any drones at the airport. Ref: Article in Techcrunch by Jon Russel “. . .police have admitted that there may in fact not have been any drones at all.”

Speculation as to what caused the concerns, confusion, and disruption of so many plans?

Rach El December 26, 2018 3:31 AM

Martin et al

i liked the comment in the media from earlier ‘ there was a meeting of Ministers, and despite the lack of evidence they all agreed there were in fact drones’

The lack of evidence would to me indicate the capacity for compensation under EU Directives, contrary to whatever the CAA say.
Disaster planning, Brexit distraction, there are several plausible motives.
I just hope there’s enough media coverage to enable to general public to have the
neccesary skepticism. It was easily the most followed story in the english speaking world for a couple of days.

Wael I am led to believe the shortest poem in existence is about fleas. You could
no doubt put an offensive interpretation on it (cough)

Had em

Rach El December 26, 2018 3:38 AM

Here’s the quote


“During a conference call between ministers, chaired by Transport Secretary Chris Grayling, it was agreed the 67 drone sightings were legitimate.”

there were ‘multiple confirmed sightings’

what is the definition of ‘confirmed’? There must be an Air Force or Avionics or military criteria for this word. ‘No footage’ doesn’t sound very ‘confirmed’ to me

Oh and I’ve seen that number 67 fall down to about 33 in other reports

there’s a story about a man who walked past a graveyard, saw his shadow and was convinced it was a ghost – had a heart attack

Wael December 26, 2018 4:09 AM

@Rach El,

You could … no doubt put an offensive interpretation on it (cough)

I remember the shortest poem was:


By Mohammad Ali. Heard that in one of his tributes.

there were ‘multiple confirmed sightings’

This’s starting to sound like UFO stuff. It probably was a weather balloon, that’s all 🙂
Wait until reports of Drone abductions and doctored videos surface – Drone Encounters of the Third Kind.

Clive Robinson December 26, 2018 7:20 AM


there were ‘multiple confirmed sightings’

Yes that is correct there were…

What you should ask is what the definirion of “confirmed” means.

In essence two or more “sights” within a similar time span.

I remember an RAF officer talking about “UFO’s” he said he had seen thousands over the years, as had others on their radar screens…

And that they changed the name in the reporting logs, due not just to the number but “crazies” thinking UFO ment Aliens had been sighted… Also Pilots commercial and civilian get to see similar oddities. It’s supprising just how high man made junk can get and stay up[1]…

You have to remember that an Air Traffic Control screen, is not a radar screen in the true sense but generated by a computer that uses the IFF squawk box to confirm aircraft and remove the clutter. Military systems don’t do that and rely on the operator to sort the clutter out in their heads.

It’s why the Air Malasia flight caused so many problems in trying to find it. Once the IFF was off it was nolonger on Air Trafic Control “radar” even though it might well have been lit up like a Hindenburg in WWI spot lights.

[1] Back in a misspent youth I and others used to make “micro transmitters” that whilst fitting in less volume than a small match box including the battery pumped out rather more than +10dbm into some “odd wire antennas”. When hung below a suitable “ballon” they could be heard across half of Europe as it then was. These days the UK Gov does not alow such flights but… Southern Ireland (Eira) has no such issues 😉 Oh and you don’t need those expensive weather ballons… You can use various products from “The London Rubber Company” which makes a special line of protectives for the British army, that I know you can get atleast 10ltrs of water in, oh and inflate with hydrogen to about 2m long and atleast one wide. If you use a thread of cotton treated in a well known chemical to make a fuse they make great “aerial mines” to scare the crap out of other soldiers, especially if you add other flamables such as a rag soaked in white spirits 😉 but they do have great lifting power to get an anoying “bug” all the way across europe…

MarkH December 26, 2018 10:43 AM


One of your comments above repeats an assurance given also on another thread, that transport planes can fly safely with an engine out.

While they are designed to do so, there’s a grave risk that practice will diverge from theory.

When an engine fails during initial ascent, or while holding a low altitude prior to intercepting glide slope, the thrust setting may be very high.

If an engine fails in such a condition, within a few seconds the total net thrust will drop by about half (for most planes nowadays), and the plane will yaw heavily in direction of the failed engine (for wing-mounted fans).

If this happens with obstacles or terrain less than a few hundred feet below, as is quite probable with a “drone” collision near an airport, then the pilot flying will have very few seconds in which to avoid a crash.

Rescuing the situation will require an exercise of airmanship far outside of what transport pilots do on a routine basis, and virtually no delay in identifying what has gone wrong and calling up the appropriate course of corrective action.

While the pilot will have practiced this maneuver in a simulator (we hope), s/he will very likely never have done it on an actual plane near the ground.

In recent years, a few fatal accidents have shown professional pilots failing to recover stalls initiated from wings near level, even though they’re supposed to know how to do that.

Compared to losing an engine close to the ground, the failed stall recoveries:

  1. Gave the flight crew much more time to react
  2. Would have required considerably less skill to execute
  3. Had probably been repeatedly practiced by the pilots in actual flight (in small planes)
  4. Started in a lower-stress context than “right above the dirt”

There’s no reason to be sanguine about survival of an engine failure when the plane is flying within not many seconds of the runway. In many cases, the pilot flying might save the ship, but the risk of calamity is high.

65535 December 26, 2018 11:33 AM

@ Clive Robinson

“It’s the reason I picked the .44 Remington magnum” –Clive R

Hum, the UK’s version of “Dirty Harry”?

That is the fire arm cartridge that made “Dirty Harry” or actor Clint Eastwood famous with the line:

“being this is a .44 Magnum, the most powerful handgun in the world, and would blow your head clean off, you’ve got to ask yourself one question: ‘Do I feel lucky?’ Well, do you, punk?” –Dirty Harry

ht tps://en.wikipedia.org/wiki/Dirty_Harry
[URL broken to avoid bots]

The same with “Magnum Force”, “The Enforcer”, “Sudden Impact”, and so on.

Say, Clive, doesn’t the UK shun hand guns – even with street police? Can an UK individual even buy a .44 magnum hand gun?

Clive Robinson December 26, 2018 2:40 PM

@ 65535,

Say, Clive, doesn’t the UK shun hand guns – even with street police? Can an UK individual even buy a .44 magnum hand gun?

Yes since 1997 (Dunblain) a UK ordinary individual can only shoot 6ft/lb a pistols. But they can buy a .44 Magnum hand gun, and legaly own it whilst living in the UK.

Just three points to note though,

1, The hand gun can not be brought into the UK unless,

2, it is in a deactivated state, or

3, unless a special permit is obtained for various strictly controled reasons (like as an armourer for the film industry or to “National Security” entities as an “Officer of the Crown”).

Thus the UK Olympic shooting team own their own weapons which can be kept in a secure armoury, but only abroad which is why they train in places like Switzerland.


Not sure what the current rules are after 12years and the London 2012 Olympics. I kind of lost interest in pistol shooting after I stopped wearing the green as I’d always regarded it not as an instrument of skill but a coup de grâce weapon when hunting or clearing vermin with a long barrel. A long term neighbour back in the 90’s was at county/country standard with .22 and was kind of devistated when it was taken away from him as a sport due to publicity hungry knee jerking politicos[1].

The reason I chose the .44 Remington Magnum was as far as I know the first “standard load” for both pistol and rifle. Whilst there had been many calibers prior that could be used in pistol or rifle they frequently had different loads and even round lengths which was a bit problematic when carbine load was used in a pistol and caused the chamber to breach or the frame to crack.

Further there are various .44 Remington Magnum “tables” up on the web that give fps or m/s readings against chamber type and barrel length.

I have a friend who long barrel box cartridge hunts game with .44 because they consider the heavy flat nosed round has good medium range stopping power good stability through light to medium cover but over all a quite short range of 150-200yards thus safer than nitro or similar rounds.

Whilst my method occasionally looks like madness there is definitely method in it which is the important point 😉

[1] The statistics back then and still today show the politicos were grandstanding and doing a “Town-v-Country” stunt[2] where “country” were portraid as “scarlet wearing toffs blowing awy the cute innocent harmless furry little creatures”.

[2] Now of course with subsequent “bin legislation” the rapid rise of vermin in “town” to much shock and horror of the significant damage they cause shows what the “country” were actually all about… And it was not “Toffs on horses” any more than it’s “pissed mingers peeing on every corner”… But stereo types buys votes as the idiocy that is mismanaged Brexit draws near all to clearly shows.

65535 December 26, 2018 9:04 PM

@ Clive Robinson

‘Can an UK individual even buy a .44 magnum hand gun?’-65535

“Yes since 1997 (Dunblain) a UK ordinary individual can only shoot 6ft/lb a pistols. But they can buy a .44 Magnum hand gun, and legaly own it whilst living in the UK. Just three points to note though, 1, The hand gun can not be brought into the UK unless, 2, it is in a deactivated state, or 3, unless a special permit is obtained for various strictly controled reasons (like as an armourer for the film industry or to “National Security” entities as an “Officer of the Crown”). Thus the UK Olympic shooting team own their own weapons which can be kept in a secure armoury, but only abroad which is why they train in places like Switzerland.”- Clive R

That is interesting.

I have a friend close to London. There seem to be some hoodlums or holligans who have access to guns so I told my friend to by a gun for protection and get a permit. But, I guess that really is not possible or feasible.

I am not sure if it is practical to buy a deactivated gun and reactivate it. I also assume that getting permit to own a gun is very difficult. I will tell my friend to get a knife and pepper spray but there probably are laws that restriction them.

When very young I saw a .44 handgun with a optic sight being fired at a practice range. The gun is tremendously loud and I would guess it could take an appendage off a preson. It surely could kill. I believe the gun was being prepared for hunting. As you noted the gun as a hunting tool. I don’t have one.

I think there still is one of those lever action rifles that can use the 44 round old/new as well as pistols. I do think there is a new lever action rifle model that fires a number of rifel rounds that also go into a pistol. So, there is some synergies. Your idea is good.

“…good stability through light to medium cover but over all a quite short range of 150-200yards thus safer than nitro or similar rounds.”-Clive R

I would guess nitro is means modern probellant or Cordite from WW2 slang. And, your friend had black powder gun. I also assume your friend could of added some 44. Modern propellant to the black power to increase the range.

I now wonder if the purchse of black powder/or modern reloading powder is even legal in the UK.

When traveling to the UK I have seen large ww2 style anti-aircraft arterially in tourist castles with what I would assue is “deactivate” large rounds…but some may actually be live rounds for all I know.

I can understand you political types would like to only have guns or armed sercurity forces for themselves and keep the public away from guns. I believe people in the States are fair well armed and don’t really trust the government that much for good or bad – trump and all. So, it is hard to say if gun control is valid. Or, to say the UK method is invalid with Bloody Sunday and so on. All very interesting.

Joule December 27, 2018 2:35 AM

“ft/lb” might have some use for measuring the thickness of shielding, but it is not a measure of energy. Which can be measured in “ft lb” (a.k.a. “ft lbf”) or N m (a.k.a Joules).

C U Anon December 27, 2018 3:23 AM

@Joule:’Which can be measured in “ft lb”‘

No “ft lb” is not a unit it is two Imperial units one of distance one weight, “ft.lb” is the signage for energy or torque units. So for that matter is “ft lbf”.

The convention even in the more archaic US Imperial signage, is symbols are typographicaly a single item not two or more white spaced items.

Curiously if you ask Google to define ft/lb it takes you to the Wikipedia article on the Foot-Pound unit. So based on the way Google claims it’s algorithms work there must be a lot of people using ft/lb out there for some reason.

Wikipedia says,

“The foot pound-force (symbol: ft⋅lbf or ft⋅lb) is a unit of work or energy in the Engineering and Gravitational Systems in United States customary and imperial units of measure. It is the energy transferred upon applying a force of one pound-force (lbf) through a linear displacement of one foot.”

Clive Robinson December 27, 2018 4:29 AM

@ Bruce and the usual suspects,

The case of Gatwick Airport gets more curious by the day…

Just heard on BBC Radio 4 news that the US GIP has sold it’s controling stake to French Vinci for £2.9Billion…

Which as you can imagine made my ears perk up, and the brain buzz with “did I just hear that right, only 3Billion…”.

So a quick look at the Grauniad web site gives,


Most curious… Obviously various people such as UK Gov ministers and even Chief Police Officers would have “been in the know” for various reasons.

But, rumours have been circulating for a while that GIP was going to sell Gatwick for between 7-10 Billion based on them selling London City airport for 2Billion back in 2016.


So the actual sell off at less than half the lower estimate of Gatwicks alleged value could be seen by some as a significant loss for GIP. I wonder how long it will be before “Brexit Panic Selling by US” or similar becomes a news headline, anyone give me odds? 😉

Clive Robinson December 27, 2018 8:23 AM

@ 65535,

I just noticed I missed an “ir” out. It should not be “a pistol” but “air pistol”.

As for getting a “fire arms certificate” or “shotgun certificate” can not be that difficult as around 1.8million weapons are covered in the UK.

Stats for 2017 are just under 155,000 FACs covering just over 559,000 fire arms (rifled weapons). With well over 561,000 FCs covering just over 1.349 million smooth bore weapons[1].

Air weapons below 12ft.lb and air pistols below 6ft.lb don’t –currently– require certificates or permits but you should be more than 14 to own one or under the supervision of some one over 18 (adult).

What is not realy clear is “ships vary pistols flares” and other signaling and weapons as many ships comming into UK teritorial waters and ports carry all sorts of arms. Some including machine guns if they have been around pirate laden waters off of the Somalian and other coasts. Officially form “IMO FAL form 3” or “IMO FAL form 4” have to be filled out but guidence about “crew paid off or transfered” was non existant last time I sailed as a ships master. I kind of get the feeling that as long as the paperwork is correct and they are under “lock and key” controled by the ships master on the vessel and are notified to the port authority and customs not much is said.

There are other rules for the transfer and storage of “bonded goods” including prohibited and regulated items, but every time you try to get guidence you get told that the legislation takes priority but when you ask what acts and statutory instruments, you get the old “bureaucratic two step” response…

The interesting thing is the difference in “town and country” response to guns. You walk down the street in a country village with a gun bag over your shoulder no one will bat an eye lid, infact seeing weapons not in cases being carried in and out of shops from vehicles is not much commented on either, the owners muddy boots however…

But carry a repaired table leg in a plastic bag in East London and some idiot phones the police the next thing you know some granddad (Harry Stanley) is lying dead on the pavement shot by two officers from behind. Then there was the Brazillian electrician (Jean Charles de Menezes) on his way to work one morning who had his head blown from his shoulders by police four police officers “double tapping” him as he sat peacfully on a tube train listening to his iPod. Then there was… Oh several others I can remember and no doubt more I’ve forgotton. My viewpoint of the Met Police officers I’ve mentioned befor and well it’s not good. Someone I used to know in the City Police who was an ex military instructor called them “A bunch of Walter Mitty types with more grunt and less sense than a troop of baboons”[2]… He surprised many of his superiors in that although he regularly shot at county and above level he point blankly refused to be an arms officer after his probation. And when once pushed apparently told a senior that the Met Police SO19 had a drinking culture and lack of sufficient discipline, thus were “unsafe”. Things have changed since then several times but changed enough[3], not that I’m aware of.

[1] This used to cover still usable field and ship Canon upto the high poundage levels. I used to know someone who had an eight pound ships canon fired for ceremonial and time keeping reasons. Likewise someone from a historic battle reenactment group who had several fully functional 4pounders with full carriage and harness. Oh and his wife had a fine collection of cauldrons which she used to teach historic “field cooking”, which I was more in shape for 🙁

[2] A phrase that has a nice pithy ring to it, I’ve shamelessly stolen and used once or twice 😉

[3] A Roman official Petronius Arbiter at the time of Nero, observed some what sardonically,

    We tend to meet any new situation by reorganizing, and a wonderful method it can be for creating the illusion of progress while producing confusion inefficiency, and demoralization.

Clive Robinson December 27, 2018 11:53 PM

@ Wael,

From the article,

The explosions lit up the sky in shades of blue visible as far as Manhattan and New Jersey. The tremors shook buildings and rattled windows, sending people running into the streets.

That is one heck of a load of energy getting released. I guess well have to wait a few hours for photos of the devestated “switch yard”.

Believe it or not that sort of thing can happen when fuses blow…

Wael December 27, 2018 11:59 PM

@Clive Robinson,

Believe it or not that sort of thing can happen when fuses blow…

Or if a drone lands in the wrong place and shorts “something”? I would imagine there are protection mechanisms for possible short-circuits, but who knows… Unlikely a drone induced event, though!

Clive Robinson December 28, 2018 9:34 AM

@ Wael,

I would imagine there are protection mechanisms for possible short-circuits, but who knows…

Mad as it might appear, it’s actually the protection mechanism kicking in that causes first the “death rattle” of the laminations or “tourtured scream” of then the casing “explosion”[1]… Followed by a Boiling Liquid Expanding Vapour Explosion (BLEVE) and a nice oily mushroom cloud with that internal Devil Orange flame.

Transformer expkosions happens more often than you would think at around 0.5%/year of power line transformers going boom. It’s worse in areas where “overhead cables” are used due to atmospheric effects causing internal insulation break down more frequently (yup wind across wires makes static electricity the same as it does with aircraft props and helicoptor rotors).

Oh and if you see one in real life those electrical arcs are very rich not just in blue light but UV as well and at the least can give you the equivalent of “arc eye” or “snow blindness” with the attendent thumping headache. At worst “Who needs eye sight anyway”…

You can see and hear from[2],


Just what happens with an “iddy-biddy wee” transformer on a consumer pole and mentally scale up to those NY pics.

Likewise larger scale events in,


Which is why there is ongoing research,


[1] There are a number of causes, the most likely is a breakdown in the windings causing a “shorted turn”. Another is the earth circuit getting disrupted for some reason such as “Moppy on his back hoe or JCB”. But a rare but spectacular one is when for some reason the switch off happens incorrectly and then whilst under full load the load gets taken off abruptly. Power lines are after all transmission lines and reflections happen and Q multiplication likewise when this happens often there is not a lot left to pick up. If of course you remembered to wear your good pair of sneakers, otherwise it might be bits of you they are looking for…

[2] Hopefully this time the links sent to me will work for you. Tell you what though they do look good on a large pad screen 😉 and you will see where the blue colour comes from.

Wael December 28, 2018 10:11 AM

@Clive Robinson,

Hopefully this time the links sent to me will work for you.

They work. Nice videos. My prediction is one day a transformer will explode and momentarily become a railgun that shoots a projectile at a jetliner. Makes a drone look like a chid’s play.

TRX December 30, 2018 5:43 PM

Transformer expkosions happens more often than you would think

About once a year in my older neighborhood, since the power utility refuses to upgrade the subgrid which was originally strung up in 1942. Some of the houses here still have their original 40-amp fuse boxes, ridiculously overloaded. (local code does not require modernization…)

So we’ll hear a “boom!” from several blocks away as the latest transformer commits electrical seppuku, the UPSs and fire alarms start beeping, and we dig out the candles and flashlights, because it takes from hours to more than a day for the power company to get things fixed.

The explosions are loud at our house; it’s a wonder they don’t blow the windows out of the houses adjacent to the transformer… at the very least, it would be a “sphincter-loosening event” for the poor schmucks who live right underneath.

Clive Robinson December 31, 2018 10:00 AM

@ TRX,

… at the very least, it would be a “sphincter-loosening event” for the poor schmucks who live right underneath.

Only the first time…

After that I would be living somewhere else, deaf or both.

Oh and,

… since the power utility refuses to upgrade the subgrid which was originally strung up in 1942.

What makes you think it’s only the “subgrid” the trend these days is “NOT preventative maintenance” but “make this quaters figures” or “profit before customers who have no rights”.

One of the things about “overhead” local distribution it is not designed for reliability. The argument is replacing wire on poles is one heck of a lot cheaper than wire in the ground. Which whilst true has a knock on effect, wire on poles is so cheap it will fail quickly say ten years tops, whilst wire in the ground well that’s expensive and thus designed to last 50-150years.

But it’s not just electricity… In south east London at the end of the Docklands Light Railway (DLR) is a town called Lewisham. Many houses still have 7lb lead water pipe in them as it was a realy realy run down neighbour hood. About a decade and a half ago die to the arival of the DLR property prices syarted to rise. Well Lewisham is not much above River Thames level but there is a very large hill called Brockly Fields around which are many old (1888) houses that are occupied by aging artists and such like. Well property developers moved in and started converting these houses into luxury flats with power showers in what was the attick etc. Obviously the old water supply was not upto it. So the utility company “Thames Water” just wound up the water preasure to the max the result all that 7lb lead pipe at the bottom of the hill started poping…

Well Lewisham has decided to “regenerate” it’s self with a skyline to match Manhattan. There are residential tower blocks going up all over the place. So where you once had eight old houses with long gardens to soak away the rain you now have 200flats and solid concrete. Thus the weight of sewage etc is massive… Have Thames Water upgraded anything? Not realy to my knowledge (I visit occasionaly) the area around the DLR has been seriously flooded out atleast five times in a decade, much of it not being shall we say “rain water”…

So guess what, they are still putting in new resedential tower blocks by the dozen and have Thames Water upgraded either the water supply or sewage take away? Not to my knowledge…

I dread to think what it will cost to do retrospectively, but then the householders in the area have no choice, and Thames Water will just hike the water charges yet again across most of London because of it… But you can bet they are never going to come down again…

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