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Britain's CAA Considers Laptop Ban on Commercial Aircraft
hayb writes "An article in Britain's The Register claims that NASA and United Airlines have conducted tests on various aircraft and have found that ultra-wideband (UWB) devices "knocked out" collision-avoidance systems and impaired instrument landing systems.
It states that the blanket ban on all devices in necessary because flight crews do not have the knowledge to differentiate between standard notebooks and ones with UWB devices."
Does anyone else think that it should therefore be possible to create a small handheld device that say looks like a walkman/personal stereo, but contains an UWB transmitter? Activate it in a heavily traveled airspace and create chaos at best...
/. and that they couldn't have thought of it themselves :) In fact why bother being on the plane, have it in the baggage hold on a timer... It's not explosives, its a harmless walkman...
Rather than just try and ban the devices shouldn't they be working on methods of blocking the signals? Or altering the collision avoidance systems to cope with the interferrance?? Doesn't this smack of really bad shortsightedness?? Even if UWB is several years away, spark-gap transmitters ought to be homebuildable and with far more power than the average UWB transmitter.
I might be giving away ideas here, but doubt that terrorists read
Just a thought, these things crop up when people try one solution to a problem, but they are just trying to prevent it. And even though people say prevention is better than cure, cure is far more reliable.
Z.
P.S. Sorry to bring the 'terrorist' angle up again but this strikes me as a stupid thing to do, even if it never occurs. When you have people's lives at risk it ought to be cure, not a reliance on prevention.
If I want to cause panic on a commercial aircraft, I no longer need to bring a bomb?
"Stand back! I have a bluetooth device!"
It's certainly not beyond question just because it's good for safety. Safety at any price is a bad idea. If it costs $1 billion per life saved, you can save a lot more lives by spending the same money on preventive health care.
Once again, the equivalence of instability with insecurity rears its ugly head.
What we appear to have is a claim that airplane electronics are extraordinarily open to interference from consumer devices. They are so open, that such devices may indeed accidentally trigger safety-critical failures in the operating environment.
Lets assume this is true.
Now understand, that which can be accidental does not need to be.
If one can accidentally down a plane with a gameboy, it stands to reason that one may be able to intentionally down the plane with the very same gameboy -- easier, in fact, because the attacker knows exactly which frequencies to exploit. This is...disturbing. I cannot imagine it very difficult to stow any form of consumer electronics, even with a "time delay" activation, inside of luggage or carryon.
Now, I'm not afraid of gameboys. See, I've *met* Boeing safety engineers. Hell, I've quoted em, learned a bit from em. Paranoid doesn't begin to describe them. These guys imagine everything, and implying that they didn't budget for even a miniscule amount of shielding and noise resistance...it's almost insulting.
Hell, you don't see planes crash every time the sun decides to belch out a few terajoules of flare in our direction. Not to mention the basic design of a fuselage bears some resemblance to an EM-blocking faraday cage.
Granted, it may very well be this same paranoia that allows those same engineers to say "Please, no new equipment, we couldn't test with that precise radio environment". The *world* is an unpredictable precise radio environment, and unfortunately, so now are its residents. I hate to say it, but if a plane can't survive a ringing cell phone, it ain't Nokia who's to blame.
That being said, the UWB failure are interesting: If the claim is that UWB operates below the noise floor relative to a given frequency, then the question becomes how did the collision avoidance systems even *detect* UWB transmissions, unless they themselves operate in a baseband manner?
One answer is that noise floors might be relative: A nearby transmitter emitting weakly across all frequencies might be overpowering the far away signal tranmitting on one. This is...hard to believe, but not impossible.
I suppose that's my biggest problem with the consumer electronics ban: Since it's inconceivable that planes are actually vulnerable to random noise from consumer electronics, *all* device-level concerns become suspect. That's annoying.
If somebody -- anybody -- has evidence they feel I should see, feel free to contact me here or in email.
Yours Truly,
Dan Kaminsky
DoxPara Research
http://www.doxpara.com
I mean, really, what this is really about is the airlines losing the 5-10 bucks they charge for those headphones so you can watch those sorry ass movies on crappy VHS.
What they really want to ban is DVD players!
This
This method could be first field-tested by a volunteer group of female flight stewards.
...but I'm still a bit amazed at how lightly people take issues like this.
Your sitting in a metal crate with two giant combustion engines delivering an insane amount of power to get you off ground.
A plane consists of several thousand electronic, mechanical, and electromechanical systems, a zillion bolts and hundreds of tonnes of lightweight metal. And any single part of this giant system might fail at any time.
The fact that accidents don't happen more often than they actually do must be considered an engineering miracle.
So, you can't smoke and sip a gin&tonic while writing some shitty design document nobody cares about and which you might as well write when you get there?
Boo-fucking-hooo
Read a book.
All people are now banned from flights, as the security crews are not able to tell the difference between terrorists and regular passengers.
This is how the slide starts....
If this were really an issue, we would be seeing terrorists with small devices built into cell phone cases that were built using a switch, a battery, a capacitor, a coil, an electromechanical relay, and a large antenna loop: a spark gap generator, of the type one makes from Radio Shack project kits.
;^)).
Or, they would just have cell phones, since they are also supposedly a source of interference with something other than AirFone revenues
In reality, this article is _mostly_ bogus.
The ILS (Instrument Landing System) is vulnerable to electronic interference, mostly because it is an incredibly ancient implementation, and has not yet been replaced with anything designed in the last two decades.
The antique ILS in even the most modern aircraft is why you can't use electronic equipment during takeoff and landing (landing is obvious; so's takeoff, if you realize that it might have to be aborted, in which case it turns into a landing).
Most airports, however, are in urban areas, with a high telephone cell density. If this were ever a real issue, we would see aircraft dropping out of the sky as they flew over any urban area. SFO, PHX, and SLC tend to have a higher than average instrument requirement (the first for fog, the second two for temperature inversion based wind shear; want to vomit? Fly Tucson to Phoneix. SLC also has snow visibility issues in winter). For most airports, the systems are largely ignored. SLC has an upgraded system that ~60% of modern planes can use, actually; it's a deployment issue.
The TCAS (Traffic Collision Avoidance System) is actually based on paired receivers. It's succeptable to powerful broad-band interferences; "powerful", in this case, means "orders of magnitude higher than the those currently permitted for use in UWB devices".
The failure you would see (and you would probably need a specially manufactured transmitter to see it) would be a 180 degree polar flip (i.e. if the transponder you cared about were 23 degrees down and 17 degrees right, it would read as 157 degrees up and 163 degrees left). This actually happens a lot, and the hardware is built to automatically compensate through multiple samples (i.e. sustained interference is required).
The fix for this is to go to trios instead of pairs of receivers.
As we saw just the other week, though, TCAS itself is generally ignored in favor of ground instructions, we lost two planes in a collision in Germany specifically because TCAS was ignored.
Given that TCAS is almost never used, anyway, because the controllers keep the planes far enough apart, the interference is isn't likely to be an issue.
In any case, I think the overall concern is a result of the fear of out-of-spec devices, which met emissions at the time of manufacture, and have since, for whatever reason, ended if with a much higher signal strength.
Personally, I think they are worried over nothing: it's just an uncommenly slow news day, what with most of the U.S. shut down for Labor Day...
-- Terry
For shrugging off a command to open up and take everyting out of his wallet. He did it but his verbal response was "Yeah you got me I keep a rifle in there."
It was on MSNBC I think. Coupled with airlines now charging up to $80 per bag to check the bag if it's over an arbitrary size and basically what you have is an industry that is committed to committing suicide. At this rate there will be 1 or 2 Long Distance Airlines that only carry passengers overseas or long distances from coast to coast or internationally outside of western Europe. And everyone else will do anything but fly, which will costs thousands of dollars anyway.
It will be a return to the 1930's except we don't have trains in the US anymore so everyone will drive in Federally mandated 8 MPG land arks - one to an SUV by law. Once in a great while we'll look up and see a jet and it will seem as strange as seeing a hot air balloon or the Concorde today.
May I ask what you think you mean by "heterodyne detection"? Because all the aviation band radios I've ever designed test equipment for were superheterodyne receivers, just like any other modern radio.
.5 GHz to 3.5 GHz.
The problem with UWB is that simple fact that it occupies the same spectrum as everything else, by design - as a result it acts to raise the noise floor of all signals.
This isn't a problem when you are dealing with a signal that is tens of decibels above the noise floor, but if you are dealing with a weak signal, like GPS, LORAN, or another aircraft's ATCRBS transponder where you only have a few dB headroom, you don't have any leeway for the noise floor to rise. It doesn't matter what supercalofragilistic sheilding you put on anything to keep unwanted frequencies out, because UWB occupies the wanted frequencies too!.
And as for the tech in aviation not changing - tell it to the trial lawyers who pounce on any excuse to sue aviation manufacturers. If anybody introduces something new, and the plane it is in crashes, then the manufacturer will be sued for putting in "New, Experimental, untested technology!" - even if the reason the plane crashed was that the pilot was drunk, stoned, and inexperenced. So neither the manufactures nor the FAA will approve any new tech without giving it a multi-decade probe.
Let me run the numbers for you on interference.
Assume you have a UWB device at 10 mW output. Assume the bandwidth is 3 GHz, centered at 2 GHz. Assume the spectral shaping is rectangular. Thus, the energy is evenly spread from
First observation: the signal overlaps the GPS frequency allocation.
OK, now what is the power density? 10 mW over 3 GHz is 3.3E-12 W/Hz.
Now, consider GPS. GPS signals are about 20.46MHz wide. That means our UWB signal will be producing 3.3E-12 W/Hz * 20.46 MHz = 6.8E-5 Watts of signal, or -11.6 dBm of signal. The signal you get from the birds is less than about -90 dBm. You UWB signal is over 80 dB HIGHER than the GPS signal. Even with the coding gain you get from the fact that GPS is spread-spectrum you are still 30 dB under the noise floor. That means you could reduce the UWB signal by 30 dB (1/1000 the power) and STILL swamp the GPS signal.
UWB isn't magic - it doesn't magically pull bandwidth from nowhere, and it WILL interfer with other signals. You want to park the signal in a band nobody else is using, like up in the THz band, great! But don't put it down with everybody else, because contrary to what its proponents say, it does not play well with others.
www.eFax.com are spammers
I know exactly what I mean by "heterodyne detection." I refer to the capability of a circuit to detect when two transmitters attempt to operate on the same frequency simultaneously. The 1977 Tenerife airport crash of two 747s (KLM & Pan Am) is frequently used as an example of (1) a heterodyne happening (it was recorded on the cockpit tapes), and (2) the need for this feature so all parties are alerted to the event.
Geez, you couldn't even type "aviation radio heterodyne" into Google to see what I was talking about. Everything I've posted comes up on the first page!
- Advanced Aviation Technology Ltd. makes a device for this purpose,
their sales pitch (section 3)
describes the problem. (How nice of them.)
- Salon posted an article
about the problem on March 28th. Same example -- Tenerife airport.
Over 500 people died in that fireball, and we still haven't standardized a solution. It's been twenty-five-and-a-half years! That's enough time to come up with a lawyer-resistant solution!Not going to bother bashing lawyers here -- this is Slashdot, feelings on that subject are well known.
"Let me run the numbers for you on interference."
Um... no. Your numbers are way off the mark. Assumptions are dangerous, you have an internet connection, why didn't you use it? Google for "FCC UWB limits" -- the first link is a whole set of info on power levels and spectrum allocation. Digging a bit deeper, you'll find:
- "...For now, UWB communications devices will be restricted to intentional operation only
between 3.1 and 10.6 GHz; through-wall imaging and surveillance systems restricted between
1.99 and 10.6 GHz (and used only for law enforcement, fire and rescue, and other designated
organizations) and automotive radars restricted to frequencies above 24.075 GHz."
Further, since you seem particularly worried about interference with GPS, I point you to this PowerPoint presentation from IEEE, or Google's rather poor HTML translation of the same thing. (It loses the graphics) The point? UWB is specifically regulated to stay out of the GPS bands.Further, maximum output -- anywhere in the spectrum -- must be under limits set by part 15 (for now). That's -41.25 dBm/MHz.
"...America's great minds of today, teaching America's great minds of tomorrow. Poor bastards." -- A Beautiful Min