Wi-Fi Shown To Interfere With Aircraft Systems

lukehopewell1 writes "It's official: using Wi-Fi on a plane can interfere with a pilot's navigational equipment, according to airline equipment manufacturers Honeywell Avionics and Boeing today. Boeing confirmed to ZDNet Australia that the issue does exist, but said it has not delivered any planes suffering the fault. 'Blanking of the Phase 3 Display Units has been reported during airline EMI (electromagnetic interference) certification testing of wireless broadband systems on various Next-Generation 737 aeroplanes,' Boeing said."

Comments

FAIL

[diskofish]

The navigational equipment should be designed so it is tolerant of this sort of interference.

Re:FAIL

[Anonymous Coward]

Low bid isn't always best. Next, we'll hear the military has the same issues.

Re:FAIL

[Anonymous Coward]

FCC part 15:

"This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation."

So you can't get certified in that case, I think, if you make the device tolerant of interference.

Re:FAIL

[the_raptor]

Go learn about RF. At the frequencies used by Wi-Fi a resonant antenna is only a few CMs long, ie about the length of common circuit traces on the PCB's. Even if you completely shield the control units RF can still leak inside through cabling. There is no magic way to design electronics that are RF immune*, it requires real world testing to discover such faults, as happened here.

The only way to make extremely RF tolerant electronics is to use analog vacuum tube based designs (the Russians continued using tube designs into the 90's).

* Making bug free software is significantly easier.

Re:FAIL

[Anonymous Coward]

Shut up. This is obviously the fault of the big corporations and their incompetancies, which us enlightened slashdotters have none of.

Re:FAIL

[LWATCDR]

My guess is that you are not an EE.
But you don't have to be to understand it in simple terms. navigation systems work in large part by picking up relatively weak RF signals. It isn't easy to do that when you have a bunch of RF transmitters sitting next to it.
Kind of like trying to listen to someone wispier in a rave.

Re:FAIL

[fuzzyfuzzyfungus]

My understanding(admittely layman's) is that not all devices are Part 15 devices. Part 15 is basically the "Go ahead and use the shitty parts of the spectrum, or have a less than totally RF-tight case; but don't fuck it up for any of the real people" license.

I'm guessing that aircraft systems may well be held to stricter standards in terms of rejecting interference; but may or may not be required to accept any interference received.

Re:FAIL

[fuzzyfuzzyfungus]

It is pretty dubiously practical; but you can carry power over fiber(bright light on one end, photocell on the other). Both the max power per strand and the efficiency kind of suck; but that does allow you to(for low power systems about which you are rather paranoid) build a completely optocoupled device...

Rarely practical(and obviously wholly unhelpful for things like radar and radio communications gear, which explicitly rely on collecting RF); but the only thing stopping you is good sense...

Re:FAIL

[The Grim Reefer2]

The navigational equipment should be designed so it is tolerant of this sort of interference.

Perhaps it will be going forward. However the average age of an aircraft you fly in today is probably in the neighborhood of 11 to 12 years old. Which means the designs for these planes are even older. Since WiFi wasn't very common (if it was at the consumer level in some cases)when the current planes were designed, it's a little silly to state the current fleet should be designed to be tolerant of it.

Maybe it will be possible to retrofit active designs in the future, but I'd guess the cost involved will be extremely prohibitive. I'd also guess even if they could retrofit all current aircraft, the testing that would be required before doing so would take years.

Re:FAIL

[imgod2u]

Most electronic designers are competent enough to put a choke at their power line and a bandpass filter at their cabling. It's not "easy" but it's done in just about any military grade electronics. I guess Boeing engineers didn't think it was necessary.

Re:FAIL

[imgod2u]

My guess is you're not an EE either. Interference doesn't quite work like that; orthogonal frequencies, for instance, do not interfere at all even when one is extremely high-powered.

Re:FAIL

[crakbone]

Some of these planes and designs are well over 30 years old. I doubt they thought back then that people would each have three or four mobile transmitters let alone the idea of putting in a big transmitter inside the cabin to coordinate a bunch of little ones.

Re:FAIL

[Pingmaster]

A resonant antenna can be found in PCB traces that are the right length, yes. These traces are usually shielded to the nines, so that stray signal does not get in. Transmission cable is also shielded to prevent extra noise coming in (there's enough of it at the antenna already). Non-shielded cabling (i.e. power) is usually protected from the sensitive stuff by means of an inductor (often called an RF choke) to block off as much of that extra noise as possible. On top of that, Antennas can be designed with a small narrow bandwidth amplifier to give the signal a boost as it enters the system, and also reduces the incoming signal bandwidth to that of the preamp, cutting out more noise. The way I see it, if they're getting enough interference from a standard strength wi-fi signal to bork the system, they have some major design flaws to work out.

Re:FAIL

[Anonymous Coward]

That would be true... If the navigational radios were operating near the same frequencies as Wifi (2.4, 5.8 Ghz) which IMO would be a massive design flaw for any mission critical system.

Re:FAIL

[Anonymous Coward]

you can carry power over fiber(bright light on one end, photocell on the other). Both the max power per strand and the efficiency kind of suck; but that does allow you to(for low power systems about which you are rather paranoid) build a completely optocoupled device...

Please provide supporting evidence for your claim. I am working in a defense industry and would love to transfer a significant amount of power over fiber. Also, Power-over-Ethernet would be very useful if implemented for fiber media, but I have not heard of any such effort.

To my knowledge, the efficiency of an optically-powered system is far too low to power nontrivial electronics in the 30-100 W range. Photocell efficiencies are very bad (4%? 10% maybe?) compared to the 80-90% efficiency you need for a practical system.

Re:FAIL

[fuzzyfuzzyfungus]

You are entirely correct when you say that optically powered systems are unequal to the task of powering anything serious. We are talking under 2 watts/strand here. Nice if you want to put an electrically powered sensor right in the middle of 'if-it-sparks-here-everybody-will-die-horribly-ville'; but you'd be looking at a real tentacle of a cable if you wanted to move serious energy.

For low power, though, it's an off-the-shelf item...

Re:FAIL

[digitig]

I guess you're not an EE either, then, because no communication system uses pure, unmodulated frequencies. And anyway, if that extremely high-powered signal is lower in frequency than the other one there's every chance it will contain harmonics that are not necessarily orthogonal to the other signal.

Re:FAIL

[jrumney]

Some of these planes and designs are well over 30 years old.

The 737 Next Generation is 15 years old.

Re:FAIL

[msauve]

"Orthogonal frequencies...do not interfere at all even when one is extremely high-powered"

Frequencies aren't orthogonal (they're scalars), signals are. If you don't control both signals, you can't control orthogonality. One must also consider the dynamic range of the front end - if overloaded with a high powered signal, the frequency relationship doesn't matter. That calls for good bandpass and roofing filter design.

Re:FAIL

[ptbarnett]

My guess is you're not an EE either. Interference doesn't quite work like that; orthogonal frequencies, for instance, do not interfere at all even when one is extremely high-powered.

And I'm guessing that you aren't an RF engineer.

It is extremely difficult (and nearly impossible, at a reasonable cost) to design and build a transmitter that only radiates RF on the fundamental frequency. It invariably radiates on harmonic frequencies (integer multiples of the fundamental). FCC regulations limit the acceptable power level for harmonics, but if the transmitter's primary power output is high enough, the harmonics can still interfere with a nearby receiver -- depending on the local strength of the intended signal.

In addition, there is the potential of "intermodulation", or mixing of two transmitted signals to produce a third signal that is a different frequency than either of the originals.

[Disclaimer: I'm not an RF engineer, either. But, this was basic knowledge required for an amateur radio license in the US, at least back when I got mine]

Re:FAIL

[digitig]

There is a definition of orthogonality for frequencies -- read up on Fourier analysis.

Re:FAIL

[Anonymous Coward]

No, it's perfectly possible to perform proper design and shielding such that a display NEVER blanks when in the presence of a Wi-Fi device.

Really, the article is short on details. There's a comment that the "EMI levels from actual wi-fi devices" wouldn't cause a problem.

It sounds like they found an EMI hole in the unit within the 2.4 GHz band - likely well above WiFi levels, but there is sufficient paranoia/concern that if there is any EMI hole in that band below whatever the established standard is for civilian aircraft equipment (I forget if RTCA DO-160 has any EMI specifications - I'm always working with MIL-STD-461C or later), even low-power transmitters are to be disabled even if they are well below the trigger threshold.

As a point of reference, depending on the specific service customer (Army, Navy, and Air Force have somewhat different thresholds), MIL-STD-461E specifies that a device is able to handle either 20 volts/meter or 200 volts/meter in radiated susceptibility tests. There are also conducted susceptibility tests, but with wifi devices, 461E's RS103 is likely where you'll fail. (But RS103 thresholds are WAY above what any FCC-compliant WiFi device could possible generate.)

I'd be shocked if they actually encountered interference from a plain old WiFi device - An EMI hole that bad in a display would most likely result in the system getting grounded immediately. It would also be best considered to be an EPIC FAIL.

Re:FAIL

[Andy Dodd]

Yeah, but this isn't a navigation system itself, it's a display unit. I agree that nav systems such as VOR/ILS, TACAN, etc. are very interference-susceptible, which is the reason for "all electronic devices off during takeoff/landing" - but that's not actually the case here.

Re:FAIL

[PitaBred]

You're a good guesser ;)

Re:FAIL

[rrossman2]

My friend works for a company that makes video distribution systems for airlines (such as Lufthansa). The amount of testing that goes into it is crazy. He's one of the guys who runs all the tests in a Faraday cage and what not. The connectors they have to use to meet FAA regulations and all that are crazy.. the plugs have 16 mini-philips head screws in them to keep the plug from ever working its way loose among other things. They also use Cat 6 and 7 cables for the distribution.. he said no fiber optic lines since the installers/mechanics tend to zip tie or otherwise fasten the stuff too tight and snap the cables.

With all of those regulations and testing they do just for a freaking video distribution system, it makes you wonder how the more critical components were designed that a WiFi signal can screw them up..

Re:FAIL

[kangsterizer]

The new slashdot meme:
IANAEE.

Re:FAIL

[mangu]

Most electronic designers are competent enough to put a choke at their power line and a bandpass filter at their cabling. It's not "easy" but it's done in just about any military grade electronics

And to play a violin all you need to do is to draw the bow across the strings. There's a lot more to this than theory.

A choke is inductive at a limited range of frequencies, at other frequencies it acts as a capacitor. Likewise, put a high enough frequency across a capacitor and its behavior becomes inductive. Electromagnetic compatibility (EMC) is a very complex subject, there are no easy solutions and it's nearly impossible to have a perfect solution that works at all frequencies.

The 2.4 GHz band used in WiFi is one of the most difficult to shield. All the small metallic parts used in electronic equipment, like screws and button levers, are in the same size magnitude as the wave, so there are plenty of conductive parts to retransmit and conduct the radio frequency.

I guess Boeing engineers didn't think it was necessary.

You guessed wrong.

Re:FAIL

[Anonymous Coward]

Or, we could use materials in the cabin that shield WIFI from penetrating into areas where it may cause issue.

You do know such things exist, right?

Re:FAIL

[Khyber]

"The only way to make extremely RF tolerant electronics is to use analog vacuum tube based designs"

What? Really?? Please tell that to my properly-grounded solid state guitar amplifiers. I used to pick up radio stations before redoing the grounding, now it's dead quiet.

Learn to ground things out properly and RF is NEVER an issue.

Doesn't surprise me Boeing would discover this, the grounding on their planes is atrocious. I've shocked myself multiple times just boarding the damned things.

Re:FAIL

[Anonymous Coward]

How?

Re:FAIL

[Anonymous Coward]

Not as funny as I ANAL.

Re:FAIL

[Khyber]

Photocells are climbing towards and passing 30% efficiency, and that's when exposed to the full visible EM spectrum.

"Please provide supporting evidence for your claim. I am working in a defense industry and would love to transfer a significant amount of power over fiber"

I work in optoelectronics. What fuzzy states is absolutely TRIVIAL to accomplish, and given the (typical) monochromatic nature of a laser, it's quite simple (well not really,) to build a PV that reacts to that range with higher efficiencies than a panel meant to absorb as many wavelengths as possible.

Re:FAIL

[Khyber]

"because no communication system uses pure, unmodulated frequencies."

Quantum radio, using spooky effect of entangled particles to act as bits.

I guess you're not a physics major. I am an EE in the optoelectronics industry.

Re:FAIL

[jenningsthecat]

The only way to make extremely RF tolerant electronics is to use analog vacuum tube based designs (the Russians continued using tube designs into the 90's).

Tube-based designs are no more tolerant than semiconductor-based designs, as far as interference is concerned. What tube-based circuits DO tolerate better is EMP's, (Electro-Magnetic Pulses), from sources such as nuclear blasts - that's why the Russians continued using vacuum tubes. EMP's will damage or destroy destroy most semiconductors within range, (often even in equipment that isn't powered at the time), but properly hardened vacuum tube circuits usually survive.

Re:FAIL

[mcavic]

this device must accept any interference received

That doesn't mean that in order to be certified, the device has to be susceptible to interference. It means that particular device may be susceptible, even though it's certified.

Re:FAIL

[the_raptor]

Yes, the modern "network centric" war-fighting model will be blown away by even a moderate EMP. Modern fighters can't even fly without electronics, and building a Faraday cage into their skin is neither practical or guaranteed to protect them from a nuclear caused EMP.

Re:FAIL

[the_raptor]

They are more tolerant because they run at high voltage. A few mV can easily cause an IC gate to flip but is drowned out in the noise in a tube.

Re:FAIL

[ocdscouter]

Which is right up there with I M HO.

Re:FAIL

[inviolet]

FCC part 15:

"This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation."

So you can't get certified in that case, I think, if you make the device tolerant of interference.

The real purpose behind the wording of that rule is to clarify who shoulders the burden of resolving RF interference. This is relevant when your neighbor operates a ham radio and it interferes with your telephone. If he is prudent then he will offer you advice and maybe some ferrites in order to clear up the problem, but the problem is legally your responsibility to resolve, not his.

Re:FAIL

[msauve]

In that sense, you're still wrong. Orthogonality in the sense of Fourier transforms applies to the components of a single signal - the frequency components are correlated. Orthogonality applies to the frequency components within the signal (they have a phase relationship, they're not scalar), not to frequencies themselves. When you're talking about 2 signals (desired and interference) which have no definite relationship, "Fourier orthogonality" doesn't apply.

Re:FAIL

[Anonymous Coward]

The 2.4 GHz band used in WiFi is one of the most difficult to shield. All the small metallic parts used in electronic equipment, like screws and button levers, are in the same size magnitude as the wave, so there are plenty of conductive parts to retransmit and conduct the radio frequency.

You're full of horseshit.

Re:FAIL

[Wyatt Earp]

737-NG has been in operational since 1998, so no they aren't over 30 years old.

767-600 came out in 1995 and was first operational in 1998
737-700 came out in 1993 with first operational aircraft in 1998
737-800 came out in 1994 with first operational aircraft in 1998
737-900 came out in 1997 and was first operational in 2001
737-900ER came out in 2006 and was first operational in 2007

Re:FAIL

[delt0r]

A choke here and there does not even begin to solve the problem. Detailed full EM simulation (time and frequency ) is start. But only true testing with actual components really gets you there. Even solder blobs can turn a unsusceptible board into a susceptible one.

Commercial airline specs are so similar to mil spec that they are often interchangeable.

Re:FAIL

[delt0r]

And what does a nonlinear element do to such a signal?

Re:FAIL

[Wyatt Earp]

Except for the fact that the US has spend hundreds of millions of dollars over decades testing EMP effects on American weapons and hardening those weapons.

As do the Europeans, Chinese, Japanese and the Soviets used too

http://en.wikipedia.org/wiki/File:E-4_advanced_airborne_command_post_EMP_sim.jpg - EMP generator at Kirkland AFB

And here is a company that does corporate EMP testing - http://www.dtbtest.com/EMP-Testing.aspx

Do you really think the US military is incapable of flying bombers and fighters in a nuclear environment?

Re:FAIL

[Wyatt Earp]

The planes in question, 737-NG are never going to be more than 13 years old with the designs dating back in 1993 at the earliest.

Re:FAIL

[eth1]

.. he said no fiber optic lines since the installers/mechanics tend to zip tie or otherwise fasten the stuff too tight and snap the cables.

Wait... so basically he's saying that they can't use fiber because the techs building and repairing the aircraft are incompetent? That certainly makes me feel better... How is "x fastener should only be y tight" any different from "the bolt holding this important piece of engine together should be torqued to y ft-lb?"

Re:FAIL

[blacklint]

I'm not commenting on the tubes/semiconductor debate because I don't know enough, but where are you going to get a good ground at altitude? You could have a common ground throughout the (metallic portions of the) plane, but that's a far cry from having the infinite source/sink that is an earth ground.

Re:FAIL

[digitig]

If the particle came into existence at some point, it's not a pure frequency. I guess you're not a math major...

Re:FAIL

[Anonymous Coward]

Well instead of shooting for the moon, why (in Gods name why), could they just not wrap the E&E pit (Electrical & Electronics pit, just below the cockpit where avionics are housed), in a Faraday cage. Its a zillion times easier, lighter and cheaper than doing basically the same for every piece of equipment on the plane. They could put a thin grounded sheet between the cockpit and passenger cabin and likewise do the same for the cockpit.

Re:FAIL

[dgatwood]

Or heck, how about using fiber optic cable with a thicker jacket so that you can pull zip ties as tightly as you would for copper cables?

This is about like saying, "I can't store my backups on any optical media because CDs are too small."

Re:FAIL

[MozeeToby]

Because "Oh, those lines are just for the entertainment system, just synch them down tight so we can move on to overhauling the engines"

Re:FAIL

[kelemvor4]

Doesn't the military generally go with the highest bidder?

Re:FAIL

[TheLink]

where are you going to get a good ground at altitude?
Just fly the plane into a mountain. Once it achieves a good ground contact, you won't have any Wi-Fi interference problems.

Re:FAIL

[gstrickler]

You're a Ho?

Re:FAIL

[advocate_one]

oh I've seen it alright... When taking photographs so I could write the removal and installation instructions for the fiber-optic databus on the Eurofighter, I got mad when I saw the assemblers were standing on the fiber-optic harnesses while fitting other items into the avionics bays...

Also, the coaxial cable used to transmit RF signals from the detector heads on the top of the fins on Tornado aircraft have to pass right down the spine tunnel and the slightest over tightening of the cable ties used to secure them or dent in the cable from impact with tools and other equipment during servicing damages the cable such that the signal is massivley attenuated... they all had to be replaced in prep for gulf war one... it was a nightmare...

Re:FAIL

[dgatwood]

Mod parent up, not down. The 2.4 GHz band wavelength is nowhere near the size of screws. A full wave antenna is just shy of 5 inches long—hardly the same magnitude as most screws. Even a quarter wave antenna is longer than most things that we'd call screws. Structural bolts are that length, sure, and some sheetrock screws, but....

And even if you go with a fairly paranoid requirement of having no gaps in your shield more than 1/20th the wavelength, that's still a quarter inch gap we're talking about....

It seems to me that what we have here is not a case of it being hard to shield at those frequencies, but rather a case of the manufacturer shielding their gear just well enough to prevent their parts from interfering with anything else, without giving any real consideration to outside interference.

You want to know what's hard to shield against? 50/60 Hz mains hum. If you want several skin depths of shielding, you'd need inch-thick copper bars.... Compared with that, a little foil tape around the seams seems pretty darn easy.

Am I missing something?

Re:FAIL

[dgatwood]

To be fair, the design still predates Wi-Fi by a good four years, and even the actual release of the hardware in 1998 predates the popularity of Wi-Fi by several years.

Re:FAIL

[Wyatt Earp]

Thats true except for 737-900s and new components from vendors like Honeywell (this example) are designed in the world of WiFi and other 2.4 GHz devices.

Re:FAIL

[EMCEngineer]

Yes, you are. Boeing is anal about EMC. They have detailed requirements for test plans and nothing is going on the plane until it has passed at minimum a safety of flight test. Anything that will affect flight performance is going to be tested for susceptibility, and not just emissions.

Power line frequency is significantly less of a problem. Most electronics are not going to be affected by anything at those frequencies because of the huge wavelength. I've seen equipment that has no issue with a 30 kV/m test at 60 Hz, but will have failures at 30 V/m in the 10-100 MHz range.

That said, I am surprised something like this made it through. Having worked with engineers from both of these companies, this should have been caught earlier. My best guess is that they did not test specifically at 2.4 GHz because at the time it was designed, wireless was not a concern.

Re:FAIL

[Obfuscant]

Wait... so basically he's saying that they can't use fiber because the techs building and repairing the aircraft are incompetent?

No, basically he's saying that the technicians who build and repair systems are technicians and not fully-trained RF and electrical engineers.

How is "x fastener should only be y tight" any different from "the bolt holding this important piece of engine together should be torqued to y ft-lb?"

Because there are torque wrenches designed to be used to tighten bolts and nuts, that are calibrated by the maintenance crew. While some cable tie guns have adjustments, they are uncalibrated and subject to many factors that make them unreliable -- at least to aircraft standards. I've had cable ties "cut" while still loose just because the tie bound up; I've had them not cut without a huge pull force. Same gun, same kind of tie.

Also because there are literally thousands of ties keeping cable bundles together in modern systems, and making them all subject to torque specifications would require a four week maintenance cycle as every tie was removed and reinstalled during regular preventative maintenance. Unless you can come up with a way to test the tightness of a cable tie you can't reach without disassembling the wing...

Putting enough jacket on a fiber optic cable to keep it from breaking under any circumstance would increase the weight to the point that it becomes heavier than copper.

Re:FAIL

[Samantha Wright]

These are different kind of bids. Or is this a woosh waiting to happen?

Re:FAIL

[DerekLyons]

Most electronic designers are competent enough to put a choke at their power line and a bandpass filter at their cabling. It's not "easy" but it's done in just about any military grade electronics. I guess Boeing engineers didn't think it was necessary.

Doing so for every wire at every point where the wire enters/leaves a shielded enclosure is heavy and expensive. It's little wonder Boeing engineers wouldn't think it necessary. Doubly so since the maintenance on such enclosures is somewhat more expensive than on ordinary boxen. You have to take considerable care when opening/closing them to avoid damaging the gaskets, and you have to take extra care when installing them in an aircraft to ensure a proper ground.

Re:FAIL

[sycodon]

According to TFA this was caught during testing.

The problem I see is all the equipment flying around that was built and certified BEFORE this testing was mandated. And it's much more than you think.

Re:FAIL

[Obfuscant]

Learn to ground things out properly and RF is NEVER an issue.

You're right. I have had intermod issues at a hilltop site I've got a repeater at. I tried simply "grounding out" all the other users antennas, but that didn't solve it. What did solve it was "grounding out" my own antenna. No more intermod issues. At least nobody has come up on air reporting any. Very quiet ...

Re:FAIL

[spmkk]

There is no magic way to design electronics that are RF immune...

He didn't say it should be immune, he said it should be tolerant. Ensuring that zero external RF emission gets in may be impossible, but making sure that once it's there you can handle it without crashing certainly isn't.

The only avionics components that should be even remotely susceptible to Wi-Fi interference are RF sensors whose measurements might be skewed by the presence of external EMI. Protecting even the most sensitive computational and display circuitry from Wi-Fi and other low-level RF interference is something we've been able to do for decades.

If your display goes blank when someone fires up their Wi-Fi card, you haven't failed to solve a difficult problem -- you've failed to solve an easy one. It makes me wonder what else in your design isn't fault-tolerant.

If Dell's engineers could design a laptop 10 years ago with a Wi-Fi transmitter *built in* that didn't crash when you surfed the web and sell it to the consumer for $2K, I have to believe that this achievement is not out of reach in 2011 for top-end engineers who design aircraft nav/display units that sell for tens of thousands.

Re:FAIL

[Anonymous Coward]

As a UK ham radio licencee, I've never really understood how to interpret that FCC terminology. What does it mean a "device must accept any interference... including interference that may cause undesired operation"? In what way is it "accepting" it?

I can understand that the user may have to accept "interference [causing] undesired operation", i.e. providing other spectrum users are operating within their licence terms, it's the user's problem. But, since the device may malfunction, in what sense is the /device/ accepting it? Does it mean that the device must not fail dangerously?

Re:FAIL

[russotto]

My guess is you're not an EE either. Interference doesn't quite work like that; orthogonal frequencies, for instance, do not interfere at all even when one is extremely high-powered.

In the air, no. In your equipment, almost certainly. Intermodulation and cross-modulation happen.

Re:FAIL

[TheCouchPotatoFamine]

(fellow ham here, making a guess, as i read it) "accept" here means that it must not fail because of such interference. Example: if your ipad crashes because of your cell phone, it has not "accepted" the interference. The connection may not *work*, but it has to fail gracefully, i.e. merely not have a connection, not blow out, spark and fizzle, or fail to note it's signal is being corrupted.

sound about right, guys?

Re:FAIL

[jpvlsmv]

The 2.4GHz band is hard to shield? Funny, I don't get a warm fuzzy feeling when I'm standing in front of my microwave.

Re:FAIL

[element-o.p.]

Well, for one thing, I can buy a torque wrench at Sears, but I've never seen a zip-tie puller with a torque/force meter on it...

Re:FAIL

[digitig]

[sigh] Orthogonality is a mathematical property of pairs of functions. There is no requirement that the functions are combined into a signal; in fact, Fourier analysis is done by multiplying the signal in question by a series of sinusoids that are not part of the signal. "Orthogonal frequencies" does assume that the frequencies in question are the frequencies of sinusoids, but no competent EE could miss that assumption and need it stated.

Re:FAIL

[ocdscouter]

You're a Ho?

I prefer Card-Carrying Veteran of the World's Oldest Profession.

Re:FAIL

[msauve]

LOL. Obviously, when they're combined, they are part of the signal. Conversely, they are components of the Fourier transformed signal. You're missing the fact that in either case, they are correlated, defined as functions which start at 0 and which continue perfectly and indefinitely. You can do that for, say, OFDM, because all the components to be combined are locked to the same oscillator, so they stay in sync. (or, in the case of reception, the receiver is phase locked to the incoming signal).

In the real world (hello???), the interfering signal isn't locked against the desired signal, so they're not orthogonal. No oscillator is mathematically perfect. No amplifier/transmitter is mathematically perfect. No filter is mathematically perfect. No receiver is mathematically perfect. A 2 MHz signal, with it's alway present first harmonic which isn't shown by your math, will interfere quite easily with a desired 4 MHz one, although they would be orthogonal Fourier components if part of the same signal.

You need to get some real world experience, that book-learning isn't doing you any good. Mathematically, a 2 MHz signal is orthogonal to a 4 MHz one. Real world, you can't have either, and you will get interference.

Re:FAIL

[Anonymous Coward]

I guess Boeing engineers didn't think it was necessary.

From the summary:

Boeing...said it has not delivered any planes suffering the fault

Unlike electronic design, reading the summary is easy. I guess imgod2u didn't think it was necessary.

Re:FAIL

[microcuts]

are you serious? Most planes out there are older than a lot of houses, and therefore were created well before WiFi, or even the PC. My employer operates seven cargo planes, all of which are older than me...

Re:FAIL

[Brett Buck]

Oh really? I think you are not correct, and Hedy Lamarr would think you are not correct .

Re:FAIL

[digitig]

In the real world (hello???), the interfering signal isn't locked against the desired signal, so they're not orthogonal. No oscillator is mathematically perfect. No amplifier/transmitter is mathematically perfect. No filter is mathematically perfect. No receiver is mathematically perfect. A 2 MHz signal, with it's alway present first harmonic which isn't shown by your math, will interfere quite easily with a desired 4 MHz one, although they would be orthogonal Fourier components if part of the same signal.

If you look through the thread you'll find that I made exactly that point.

Re:FAIL

[tomtermite]

It is common that anything in the states with FCC transmit/receive approval should not interfere with other devices; perhaps Boeing needs to shield their equipment better?

Re:FAIL

[digitig]

The whistle that Hedy Lamarr requested would have had a beginning at least, and almost certainly an end, or it would not have communicated useful information. As soon as a pure sinusoid is bounded it ceases to be a pure sinusoid (the start and end are a form of amplitude modulation, if you like, used to signal one bit of information).

Re:FAIL

[Anonymous Coward]

Go learn about software correctness. Just termination is, in general, undecidable. Almost any interesting property of a computer program is undecidable for arbitrary inputs. For typical developments, software verification is even harder than hardware verification in terms of number of states.

Making bug free software is significantly easier? Try yourself!

By the way, analog vacuum tubes are, by no means, the only way to make GHz RF tolerant electronics.

Re:FAIL

[msauve]

Right. When you originally said "Orthogonal frequencies...do not interfere at all even when one is extremely high-powered" which is completely incorrect in the context of radio interference.

Meh, no sense going further, not only don't you understand the difference between theory and practice, but you can't recognize or admit when you're wrong.

Re:FAIL

[digitig]

Right. When you originally said "Orthogonal frequencies...do not interfere at all even when one is extremely high-powered" which is completely incorrect in the context of radio interference.

I didn't say that. That was imgod2u, not me.

Re:FAIL

[Khyber]

Airplanes have easily taken lightning strikes.

They're grounded enough externally. There's enough surface area to absorb and dissipate massive electrical charges. It's the crappy internal grounding that concerns me.

Re:FAIL

[dgatwood]

Wi-fi still wasn't particularly popular in 2001 when the 900s started shipping. If there was any integrated Wi-Fi at all back then, it was the exception rather than the rule. It was an optional card in Mac laptops at the time, and an external card on most Windows machines.

Now if you'd said that the 787 had problems, I'd start to worry.

Re:FAIL

[mjwx]

Some of these planes and designs are well over 30 years old..

Because Boeing and Airbus never update the avionics.

Re:FAIL

[DMUTPeregrine]

They exist. EvilMadScientist wrote a blurb about them a while back. Google for cable tie installation tool for a lot more.

Re:FAIL

[tehcyder]

The new slashdot meme: IANAEE.

Admitting that on slashdot is a bit like saying you're rubbish at computers and don't like maths much.

Re:FAIL

[kangsterizer]

That shows where slashdot is going!
Oh wait.

Sarcasm aside EE is electronic engineer, most slashdot readers are supposedly noob teena^H^H^H^H^H software engineers, most don't have a very detailed experience with electronics

Re:FAIL

[element-o.p.]

Huh..."Learn something new..."

Re:FAIL

[blacklint]

Surviving a lightning strike unscathed is a result of the conductive airframe acting as a Faraday cage, protecting the internal electronics. Very different than trying to protect against EM radiation generated from inside the plane.

West Wing

[Sonny Yatsen]

The West Wing had a quote from Toby Ziegler that essentially sums up how I feel about this:

Toby Ziegler: "We're flying in a Lockheed Eagle series L1011. It came off the line 20 months ago. It carries a Sim-5 Transponder tracking system. Are you telling me I can still flummox this thing with something I bought at Radio Shack?"

Re:West Wing

[Richard_at_work]

That phrase has always bugged me, since the L1011 ended production in 1984 and The West Wing didn't start airing until 15 years later ... come on, get the time lines correct! Other than that, brilliant series and very sad to see it go :(

Re:West Wing

[geekoid]

Yes, yes they are because it's true.

Another point of ignorance spread through entertainment. But hey, you saw it on a magic box so it must be true.

Re:West Wing

[Anonymous Coward]

You can flummox it up with a bag of something you can find on a common farm too.

Re:West Wing

[Anonymous Coward]

The West Wing had a quote from Toby Ziegler that essentially sums up how I feel about this:

Toby Ziegler: "We're flying in a Lockheed Eagle series L1011. It came off the line 20 months ago. It carries a Sim-5 Transponder tracking system. Are you telling me I can still flummox this thing with something I bought at Radio Shack?"

Awww, poor self-entitled twit can't use his wi-fi so he pulls TV show quotes out of his asshole.

Oh, there's a whole lot more electronics on a modern-day airliner than a single transponder, you arrogant "my toys are so important I need to use lame TV quotes" shithead.

Epic Fail

[raymansean]

How in the world are new devices developed and approved for production that ignore the possibility of EMI from portable devices? There are no excuses for such negligence.

Re:Epic Fail

[mysidia]

Obviously. The Phase 3 DUs are flawwed.

On a Boeing Business Jet fitted with in-flight connectivity, for instance, there is a note in the log book that says Phase 3 DUs are not to be installed, but that "version 4 is fine and version 2 is fine", says a source.

Wi-Fi is probably one of MANY things that can interfere with flawwed, improperly shielded electronics.

Re:Epic Fail

[Anonymous Coward]

Put another way: How in the world are new devices developed and approved that ignore the possibility of EMI on large, expensive infrastructure? There are no....

Re:Epic Fail

[TheOldFart]

Maybe they used a 1kWatt wifi transmitter right next to the equipment being tested... Like when they test mice for radiation tests using 10^6 times the amount one would reasonably be exposed to...

Re:Epic Fail

[gstoddart]

How in the world are new devices developed and approved for production that ignore the possibility of EMI from portable devices? There are no excuses for such negligence.

Having worked in the airline industry for a while ... these things take years to work their way through because there's so much regulation around it.

Order a plane now, and it will take a couple of years to get your new plane. That plane and the components it uses have been through an exceedingly long design cycle in order to get all of the components working as they need to.

In this case, I suspect it's a combination of the fact that it would probably take some number of years to design, test, and get approved new devices ... and the fact that since such things have been disallowed on aircraft for a long time, they continue to assume they will be disallowed. They also design these things for 20+ year lifespans, so they have different design goals than making sure you get to have wi-fi.

Why is it so hard to understand that something as complex as an aircraft has a very long engineering cycle? Are you under the impression that making an airplane is a simple task?

Hell, the Space Shuttles run/ran on computers that we'd mostly laugh at nowadays. I bet some medical devices don't do so well in the presence of such things either.

Re:Epic Fail

[Anonymous Coward]

And now the planet knows that you need only a portable router with a beefed up output to bring one down.

Re:Epic Fail

[raymansean]

I do not expect to use any electronics that transmit or receive radio data on a flight. However, as an engineer I do expect that someone will forget to turn off the radio on their device. Thus if I was designing flight control hardware, I would want to ensure that my equipment would not be adversely affected by someone who forgot to turn off their device(s).

Re:Epic Fail

[fuzzyfuzzyfungus]

Given the relatively stringent standards for commercial pilots(who are likely the bulk of 737 fliers, along with a few uber-wealthy VIPs who have a personal motivation to hire good pilots, these aren't your single-engine hobbyist-killers here), "bring one down" is almost certainly a severe overstatement.

Seriously inconvenience? Quite possibly. Fuck with the relatively tight timeslot scheduling of the nation's busier airports, causing millions in inconvenience? Conceivable. Cause the plane to automagically fall out of the sky the moment that the pilots have to break out the map and stop staring at the screen? Pretty unlikely...

Re:Epic Fail

[AlecC]

Since the report shows that the flaw was detected in testing, they are not doing so. No doubt they were designed not to be susceptible, but being human the design did not achieved that goal. Rather then assuming that they were designed right, they were testing them - which necessarily requires production units to test. And the test showed a flaw, and they are not rolling out the systems because of the flaw.

This is the system working properly. Proper testing before aircraft delivery has shown a problem, and steps are being taken to rectify the problem. The short term fix is to outlaw WiFi; when they have found and tested a proper fix, they may (assuming tests are passed) then enable the equipment.

There is no point in getting alarmed when the proper test show the faults before the aircraft leave the ground.

Re:Epic Fail

[Anonymous Coward]

If there is a 20 year design cycle, then even at 1991 there should be an expectation that there might be a radio source that your electronics have to deal with - and it might not be accidental, but deliberate and malicious since terrorist threats such as Lockerby bomber had already happened and were much discussed back then.

If planes designed 20 years ago would crash due to deliberate wireless interference, then this is epic fail of those designers.

Re:Epic Fail

[jrumney]

It's not only forgetting that is a problem. I discovered on a recent flight that my phone will power itself back on to alert me of an appointment.

Re:Epic Fail

[geekoid]

The Epic Fail is yours. Specifically your desire to spout off about things you don't know about. Hey, why don't you study RF for a few years then put your opinion in? no, of course not. RF engineering is hard and takes smart people, and you are lazy and stupid.

Re:Epic Fail

[natehoy]

Right, but the problem is that when most airplanes that are flying today were designed (and in many cases even built) when we were all using analog cell phones and WiFi didn't exist.

So, while I admire your vision, it's hard to design hardware that accommodates for things that don't yet exist.

Re:Epic Fail

[natehoy]

Even your "single-engine hobbyist-killers" have zero dependence on high tech hardware to fly a plane safely. If you're flying VFR (clear view, etc), then a map and your eyeballs are all you really need. Well, those and the map-reading skills you had to demonstrate to a certified FAA instructor within the last two years or you wouldn't be flying.

Instrument conditions might get a bit dicey, but you've got a map of the area and know what general area you're in when you lose all the fancy gizmos and gewgaws, so you start dead-reckoning terrain avoidance, fire up the DME or VOR gear, figure out precisely where you are, and set course for somewhere with fewer things sticking into the sky. If all of that is dead, you'll always have a compass/DG, airspeed indicator, and altimeter. Climb up to well above any local obstructions, and head in the general direction of somewhere the weather isn't so bad.

But, yeah, the real problem is that of congestion. Fortunately, there are always backup plans on top of backup plans, and the chances of two aircraft attempting to occupy the same airspace are very slim, even if all communications died simultaneously to all aircraft along with every aircraft's internal electronic navigation systems, even in Instrument conditions. Obviously it would impact air travel pretty badly, and a lot of people would be staying on the ground or flying to airports they didn't really want to go to, but it's very unlikely it'd kill anyone.

Re:Epic Fail

[Anonymous Coward]

Right, but the problem is that when most airplanes that are flying today were designed (and in many cases even built) when we were all using analog cell phones and WiFi didn't exist.

So, while I admire your vision, it's hard to design hardware that accommodates for things that don't yet exist.

And they cant upgrade them? When new emission laws are introduced affecting cars we're expected to alter our vehicles. Why cant a company that
gets massive handouts from the government when they lose money but still pays its executives millions in bonuses do the same?

Oh yeah.. companies dont live in the same world as we do.

I wish that I as a person could declare myself a corporation. I'd get to ignore laws I dont agree with, pay less tax. Almost nothing I do would
result in a prison sentence and if things get really bad I just close my corporation and start another one.

Re:Epic Fail

[natehoy]

And they cant upgrade them? When new emission laws are introduced affecting cars we're expected to alter our vehicles.

Reality check: Every emissions law that's come out has held each car to the standard for the year in which it was built, along with an allowance for wear-and-tear. I've owned older cars in three states where emission controls came in, and never had to do a blessed thing to any of my cars except one that needed a slight tune-up (that ended up saving me gasoline). So let's stop the humaniform constructions out of wheat chaff, please?

Replacing the instrumentation on an aircraft is not a trivial matter. In small planes, it can be tens of thousands of dollars. In a commercial plane, I'm thinking hundreds of thousands.

If you think airfare is expensive now, think about what it would cost if a government mandate came down to change out all the electronics in every plane every 5 years when a new consumer technology comes out that might interfere with it. It would be a massive investment, then when the next gewgaw comes out that uses a possibly-interfering system, they'd have to go through it all over again.

WiMax might be a problem with GPS, so, what, you expect the aviation industry to build out a new navigation system? No. It's only a problem if the transmission is inside or very near the plane (or at very high power), because it is not orthogonal to GPS frequencies and might interfere. So carriers have to tell people they can't use WiMax on a plane, the government needs to recall the frequencies it sold near the GPS band, or new GPS birds need to be orbited. Which one is easiest?

Spectrum is precious, everyone wants some, and we all gotta share it. That means we can't afford to completely stop all wireless transmissions just because one industry (aviation) needs clear comms. So aviation has to adapt to an ever-changing and ever-narrowing amount of available wireless spectrum. In the meantime, since the communications landscape shifts constantly, they have to do their best to control interference.

Re:Epic Fail

[blair1q]

They get a sticker from the FCC that says "this device must tolerate interference from other devices and must not interfere with other devices" or words to that effect.

Then they're not responsible if you use them for something safety-critical and interference brings down your business.

That said, the FAA is not the FCC, and has its own hardware-certification process (DO-254). It specifies that something like Wi-fi, when used for entertainment purposes in the passenger cabin, must not interfere with navigation and control electronics on the flight deck.

Expect to be told to turn your electronics OFF for the duration of the flight on any aircraft not specifically certified to be free of the problem TFA discusses.

Re:Epic Fail

[tepples]

I do not expect to use any electronics that transmit or receive radio data on a flight.

Then what are kids supposed to do on a multi-hour flight if not play multiplayer over ad-hoc 802.11b on their DS, PSP, or iPod touch video game systems?

However, as an engineer I do expect that someone will forget to turn off the radio on their device. Thus if I was designing flight control hardware, I would want to ensure that my equipment would not be adversely affected by someone who forgot to turn off their device(s).

And if that fails, you could include equipment in the walls to trilaterate

Re:Epic Fail

[jonescb]

When these things were designed in the 80s and 90s, I doubt many of the engineers expected hipsters with iPhones and laptops to be onboard.

Re:Epic Fail

[Anonymous Coward]

In the meantime, since the communications landscape shifts constantly, they have to do their best to control interference.

Which is nothing it seems.

Re:Epic Fail

[natehoy]

They ask people to turn off their electronic devices.

Sorry, did you have an equally affordable and practical solution you posted in white-on-white text that the rest of us missed?

New consumer electronics comes out every couple of years. Protecting the multi-million-dollar aircraft from your shiny new $200 iBauble would cost the aviation industry millions or maybe even billions of dollars a year that you'll see added to your ticket cost.

4 options, you choose:

1. Your airline ticket prices increase by a factor of ten, and all aircraft and ground equipment are retrofitted with new gear every time a frequency is given up to general use by our congresscritters. Eventually we'll run completely out of desirable spectrum and this will be impossible, but in the meantime we can keep moving aviation, GPS, and infrastructure services out of the way of consumer electronics for a while, at increasing cost and decreasing utility.

2. The FCC does its job and stops giving out so much spectrum for use when the use of the spectrum could possibly interfere with existing systems. Of course, that means WiMax, Bluetooth, WiFi, 3G, EDGE, and GSM would not have come to pass and we'd be back on Analog TV and Analog cellular towers with precious few channels available. So their job might not be what we really want them to do after all.

3. The FCC bakes the cost of upgrades to existing systems into the licensing cost of the spectrum that's being released, so if you get WiMax you have to pay any nearby frequency-holders to vacate their territory. This is basically financially equivalent to #2, because no one is going to want the WiMax frequencies if it means they have to orbit billions of dollars worth of satellites to replace the current flock of GPS birds.

4. When a new technology is introduced that is incompatible with existing technologies only under specific circumstances, the users of the new technology are required not to use their tech in a way that interferes with the old stuff. As in, turn off your radio when on the plane. Cheap, easy, effective, expeditious, and practical.

Is it 100%? No, it isn't. But it's what we got for now, and as long as people follow the rules they can have their spectrum when it's safe to do so. So you're pretty safe from anything but short-term accidental and deliberate interference.

As to deliberate interference, any time you use Radio Frequency (and I fail to see why this is such a hard thing for people to understand), it's subject to interference. Find the frequency, transmit 1 megawatt of noise over that frequency, "game over, man!". If you want to fuck with a plane from the ground, send out a strong signal in the aviation band covering the whole thing. The information is public knowledge. There's no way to protect from it.

That's why wireless systems are NEVER used as the only way a plane works, and when they are implemented they tend to have first wireless then non-wireless backups, and if the backups to the backups to the backups fail, the pilot has clear procedures to follow, even if he's flying blind with no electrics or electronics at all (that's why many systems work on vacuum/pressure fed by the plane moving, if the plane stops moving then losing track of where you are is your smallest worry - because wherever you are, you're not going anywhere else)

Re:Epic Fail

[Darinbob]

Of course, when they build the electronics twenty years ago they most definitely had Wi-Fi in mind.

Re:Epic Fail

[Anonymous Coward]

Good God Almighty, didn't anyone read the fucking article? Here's what happened:

1. During certification testing of new equipment that has not been installed or delivered on any airplanes in existence (because, wait for it.. it hasn't been certified yet!), Boeing and Honeywell confirm that certain combinations of equipment fail the certification test. This is an FAA required test, and the FAA says: No Certification, No Fly.

2. Boeing and Honeywell are working madly to pass this test because it's holding up certification of certain options that will make them both lots of money, increasing shareholder value.

3. Equipment that does not pass this test DOES NOT FLY. See item 1.

4. Sensationalist slashdot headlines... grumble mumble bumble.

Re:Epic Fail

[smithmc]

The Epic Fail is yours. Specifically your desire to spout off about things you don't know about. Hey, why don't you study RF for a few years then put your opinion in? no, of course not. RF engineering is hard and takes smart people, and you are lazy and stupid.

Thank you for your useless, non-contributory, and unnecessarily rude comment.

Re:Epic Fail

[bartwol]

How in the world are new devices developed and approved for production that ignore the possibility of EMI from portable devices? There are no excuses for such negligence.

How, you ask? Well, really, if you wanted to know, then you wouldn't be asking such a foolish question. And you wouldn't be calling it "negligence."

How in the world do people routinely concoct unsupported technical judgements (such as yours) about things they don't technically understand, and then share those judgements with the world as if they are insightful?

Not surprisingly, most of the loudest and least articulate people are way up in the nosebleed section of the bleachers, far away from the players in the game, who, unlike you, must move beyond just [trite] words.

There are plenty of excuses for your ignorance. But none of them justifies it.

Go home.

Seriously?

[Drakkenmensch]

So they're saying that terrorists could bring down planes just by texting each other furiously?

Re:Seriously?

[Anonymous Coward]

So they're saying that terrorists could bring down planes just by texting each other furiously?

New No-Fly lists will include anyone who has registered and competed in the LG U.S. National Texting Championship.

Re:Seriously?

[digitig]

No. They're saying that terrorists could be a pain in the butt just by texting each other furiously. No surprise there. Loss of navigation systems does not bring a plane down.

Re:Seriously?

[Anonymous Coward]

Even if you were joking, this represents exactly what people don't get about these kinds of things. Most people's brains just can't evaluate a very low chance of a very bad outcome.

Suppose the odds are 1 in 100 thousand that if you use your device, you will cause a plane crash. (I am making up the number for illustration.) Then it is possible for both of the following to be true:

1. It would be completely impractical for a terrorist to use this strategy to bring a plane down. It would take an average of 100 thousand flights to finally work.
2. Assuming 100 people on a plane, one plane per thousand will go down.

Do you see the difference between one person surviving a flight in which their neighbor was using Wi-Fi, and a general policy that would allow everyone to use it?

(Note again: the above numbers involved a bunch of rough simplifying assumptions. Spare me the nit pick comments on probabilistic independence, etc... It's the point that matters.)

Re:Seriously?

[Infiniti2000]

Not necessarily. Wi-Fi does not mean texting. SMS texting is likely over the (e.g.) 3G network, not wireless broadband.

If this was really a problem...

[Anonymous Coward]

If interference from mobile phones and wifi was really an issue for aircraft they would be dropping out of the sky every day.

Re:If this was really a problem...

[digitig]

As I and others keep saying, interference with navigation systems does not make planes drop out of the sky.

End result

[Buggz]

And instead of the navigational equipment being built to tolerate wifi interference, we can soon look forward to turning in our terrorist cell phones at the security check, right before "the anonymous machine" checks your prostate. Because we live in a free country!

Re:End result

[LordLimecat]

Flying is a service you purchase from a private entity, not a human right. Dont like the security (and personally, I think its retarded and ineffective)? Get your own cessna, or dont fly.

Re:End result

[Buggz]

I actually agree, it was solely meant as a mockery, an extreme exaggeration.

While it indeed is a private entity offering this service, this doesn't mean one can't discuss how this private entity treats its customers. Secondly, the security is put in place by the airport, usually ruled by the countrys laws. The airlines themselves can't make too many demands.

Re:End result

[geekoid]

Being able to freely move between states is, in fact, a right.
The transportation method doesn't matter. The fact that they have no choice makes your argument irrelevant.

Let me know when I can choose an airline based on security options.

Re:End result

[cowboy76Spain]

Some years ago I was in a plane ready to take off when the cabin informed of "technical difficulties"

They went searching in a particular area of the seats and found someone who had forgot to turn off his phone before leaving his coat in the luggage compartment(*). It was more educational than a ton of posters asking me to turn off my cell phone.

So... well, let's say that I am that moron that will ask you politely to stop talking when the plane is going to start the take off, even if that means interfering with your freedom to do whatever you want to do, whenever and wherever. And I will keep doing, thank you very much.

Then, from my part, we are not going to use phone in planes. Never. If we are not going to use the phones while in the plane, the only caveat to giving it to an steward would be finding a good method that assures me that I will recover my phone without problems neither much delays when I arrive at my destination.

(*): Yes, you sometime did leave your phone on and nothing happened. I did forget to turn it off sometime, too. And probably if the phone of that guy had been in his pocket it would not have been detected. Or maybe it was somewhat defective. But I do not like to increase any chance of an accident for anything as trivial as what you could say in your phone.
If you want a car analogy, you can blame the government for limiting your freedom of getting drunk at a party and getting back home driving your car. And most of the times, if you do, nothing bad will happen. But that does not mean that it is not a stupid risk.

Re:End result

[blair1q]

We live in a free country because we expect to have the power to imprison and/or kill people stupid enough to interfere with our freedom, including those who think updating their Facebook page is more important than landing an aircraft full of people safely.

Re:End result

[russotto]

Flying is a service you purchase from a private entity, not a human right. Dont like the security (and personally, I think its retarded and ineffective)? Get your own cessna, or dont fly.

This bullshit justification would have a lot more weight if the security wasn't mandated (and now administered) by the government, not a private entity.

Re:End result

[Jaborandy]

Damn Straight. You don't get to use the "private entiry" or "choose a different mode of travel" arguments until I can start an airline with different security features.

My airline would require all passengers to carry and assert proficiency with a firearm. If you are proficient but not equipped, a loaded handgun can be provided for an extra fee, but all passengers over the minimum age would be required to carry.

You may not like my airline. You might never fly on my airline. But if I can't run that business and compete fairly, you don't get to tell me that it's a free country.

Re:End result

[mjwx]

And instead of the navigational equipment being built to tolerate wifi interference, we can soon look forward to turning in our terrorist cell phones at the security check, right before "the anonymous machine" checks your prostate. Because we live in a free country!

Or you could follow the existing instructions to turn off all mobile phones and radio transmitters before take off.

Oh wait, I'm the only person in the world who can follow that instruction. I'm glad that planes are made to be so ridiculously fail-safe, given the intelligence level of most of their passengers.

"Blanking"

[quacking duck]

I can't imagine a wireless signal interfering with a hardwired display this badly, so is this more an issue with wifi interfering with various sensors that feed the display, causing the system to momentarily "blank" the screen rather than present spurious and inaccurate data?

(Yes I did RTFA)

Re:"Blanking"

[dunezone]

So basically they didn't shield the components properly? Or they didn't take into account that Wifi is now offered as a service on planes so older designs were not updated?

I like the photo in the article of the plane crash from LOST. Nothing bad has happened so far because of this but lets show a crashed plane anyway.

Re:"Blanking"

[Anonymous Coward]

I read the recap of TFA over at CNET (no flames please) and the writer was quick to point out that this was during testing at power levels way beyond the operating envelope. Honeywell is researching a fix as we type.

Re:"Blanking"

[Anonymous Coward]

It's another case of shittily written/interpreted misheadlined articles that make it hard to know the real truth.

There doesn't seem to be any evidence that actual WiFi signals caused a problem - there's even a comment somewhere in one article to that degree.

What I suspect happened:
An EMI test was conducted to whatever standard is applicable to civilian aircraft
The unit failed the EMI test (probably a civilian equivalent of MIL-STD-461E's RS103 test) , and the hole occurred in the WiFi band
Even though the failure threshold was likely well above what any WiFi device could actually generate, combining that device and WiFi was banned just to be safe

Re:"Blanking"

[SparkleMotion88]

Blank display is a term used in avionics to describe a condition in which a display is blank. This condition could could be caused by any number of things, including failure of the computer that is driving the display. It's not necessarily "momentary."

Re:"Blanking"

[blair1q]

My professional answer would be "without having traced the problem to root cause, I don't know why it's blanking".

But I turn off that part of me on /., so....

It's probably something in the display itself, and nothing to do with the radar. It could be the display controller responding to spurious data from the radar by rebooting, but that'd be an awful dumb way to respond to spurious data. Usually you just put up a bug in the status bar that indicates that the source is giving spurious data. Unless some polyanna inserted a requirement that the pilot not even be able to see the display when spurious data is being processed; you get that sort of crap from the polyannas. But at the right frequency the electronics could be setting up a parasitic circuit that rectifies and voltage-multiplies the WiFi until it causes a reset or other exceptional condition in the display hardware.

Re:"Blanking"

[Anonymous Coward]

Digital aircraft displays check the output they show _with the pixels themselves_ for correctness and blank if a divergence occurs.

How can this be allowed?

[meerling]

Any plane with such crappy EM shielding is a scary thing and shouldn't be in the air with or near people.

Re:How can this be allowed?

[Anonymous Coward]

Any plane with that much EM shielding is an expensive over engineered thing and shouldn't be in the air with or near people with the extra amount of fuel required, extra parts to service, and extra fatigue hauling that extra special-case crap around.

We still have pilots and flight attendants due to their good EM resistance, and QC to catch the electronics that amplify the wrong singal.

Re:How can this be allowed?

[UnknowingFool]

True shielding can be applied; however, the cost is weight and money. For aircraft, weight is the more important factor. Plus shielding is not always simple. I only know of two planes that have undergone the effort; the twin 747s that serve as Air Force One. I think they had to strip the planes done to the frame and methodically shield everything. I think it took 18 months or something like that.

Re:How can this be allowed?

[Dunbal]

But shielding adds weight which means increased fuel costs for the operator. This is they typical aviation scenario: until a plane is downed and people die, they'll take the cheap option and pretend that potential problems can't be avoided by proper engineering. It's cheaper to tell people to turn off their devices, cross fingers and pray that everyone complies and nothing happens.

Re:How can this be allowed?

[Dunbal]

over engineered

If it's potentially dangerous, how can safety be over-engineered? Or on the other hand, if it's not dangerous at all, why even bother raising the issue?

Re:How can this be allowed?

[Wyatt Earp]

The two VC-25s (the 747-200Bs for the President), the four E-4 Airborne Command Posts (747-200) 68 E-3 Sentry (707s), 17 E-8 JSTARS (707-320s) and the 16 E-6 Mercury (707-320s) are known US civilian aircraft that have been hardened.

Military aircraft like the VH-60N and VH-3D helicopters, B-52s (which have dropped nuclear weapons), B-1B, B-2A and F-15E which are all designated as strategic and tactical nuclear strike aircraft are heavily shielded as well.

Re:How can this be allowed?

[Darinbob]

Being in the air is a risk. If you want complete safety, hide in a camouflaged concrete bunker.

Second, TFA states that this interference did not post a safety problem. They were also testing for new in-flight entertainment systems (not yet installed), the test didn't say anything about yuppies with iphones.

Ancient technology ignored...

[Eggplant62]

I guess the idea of a grounded Faraday cage around each piece of equipment escapes them?

Re:Ancient technology ignored...

[jiteo]

Grounded? It's on a goddamn airplane.

Re:Ancient technology ignored...

[gstoddart]

Grounded? It's on a goddamn airplane.

So? Why should reality get in the way of Slashdotters claiming to have a "simple" fix so they can run their wi-fi and text people wherever they want?

Because, obviously, the input of random geeks on Slashdot is far more informed than the people who actually make these things and have to build them.

Re:Ancient technology ignored...

[Richard_at_work]

Considering the amount of equipment on an aircraft, do you have any idea how much weight that would add to the MWZF?

Re:Ancient technology ignored...

[Anonymous Coward]

Plus the weight of a really long grounding wire.

Re:Ancient technology ignored...

[Quiet_Desperation]

Oh, c'mon. The antics of the Slashdot Brain Trust are priceless.

Re:Ancient technology ignored...

[umrguy76]

I guess the idea of a grounded Faraday cage around each piece of equipment escapes them?

That's going to make receiving navigation signals rather difficult...

http://en.wikipedia.org/wiki/Air_navigation

Re:Ancient technology ignored...

[geekoid]

And hoe, exactly, would they be able to receive the FUCKING SIGNAL THEY NEED TO RECEIVE ,YOU FUCK TWIT?

Aircraft is fucking complex. building them is hard. They do a lot of things. so why don't you shut the fuck up and let the adults deal with this? m/kay?

Why is it people on /. think that have a clue about avionics? This is the state of a nerd site these days. NO one knows everything and everyone is busy trying to look the part of a nerd to actually LEARN or study anything.

Re:Ancient technology ignored...

[blair1q]

All of this equipment is in aluminum boxes with hefty ground straps. Lightning protection, don't ya know. And yes, they weigh a ton in aggregate.

The signal can still leak in through the cabling, unless you add a pound of filters to every box, which, generally, they do, but again they're more focussed on their own radar and lightning frequency distributions. Wi-fi is a new thing and they don't seem to have sussed it out yet.

Re:Ancient technology ignored...

[Anonymous Coward]

I guess the idea of a grounded Faraday cage around each piece of equipment escapes them?

That's part of the problem....what's "ground" at 30,000 feet? And sure, you can put each instrument inside all the shiellding you want, but unfortunately it needs to be connected to other pieces of equipment.

I'm glad to hear you at least paid enough attention in physics class to pick up some of the buzz words.

Honeywell screws us all

[ktappe]

As everyone has said so far, this is a serious fail on the part of Honeywell for not accounting for WiFi in their engineering & testing process. But you can be darned sure this incident will be quoted for the next couple of decades by defenders of "you must keep your devices off when on board" policies. So thanks, Honeywell, for being the instrument of keeping us in the dark ages aboard aircraft.

Re:Honeywell screws us all

[drinkypoo]

Let us be sure to publicize this fact every time the subject comes up so that Honeywell's name is eventually equated with the Honey Bucket Man. Not shielding electronics used in airplanes is incompetence at best.

Re:Honeywell screws us all

[vawwyakr]

Agreed I'll have to listen to the witless repeating this BS scenario will bring the plane down. Gee hope we don't get hit by a mild solar storm while we're flying because if my phone can bring the plane crashing down then I think the sun will be able to do a much better job.

Re:Honeywell screws us all

[geekoid]

"this is a serious fail on the part of Honeywell for not accounting for WiFi in their engineering & testing process."

no it is NOT. god damn it, learn a fucking think about avionics before slap your gums together in a vain and ultimately useless attempt to make your self seem smart.

Re:Honeywell screws us all

[geekoid]

Planes fail from cascade events that always start with something innocuous. OTOH, the fact that you think a wi-fi signal and a 'solar storm' are the same thing, and that you think a 'solar storm' currently doesn't have an impact on nav control point to one fact: You are an ignorant fuck.

Re:Honeywell screws us all

[Anonymous Coward]

But you can be darned sure this incident will be quoted for the next couple of decades by defenders of "you must keep your devices off when on board" policies.

Actually, if you start yapping on your phone while sitting next to me, this will be pretty far down my list of inducements to get you to shut up. First on my list will be a tightly rolled-up copy of "SkyMall".

So if I leave wifi on?

[Toe, The]

So if I open up my laptop and start using it, it starts seeking wifi signals. Is this enough to interfere with the plane?

'cause I don't ever hear flight attendants telling people to disable their wifi (or bluetooth, etc.). Just to "turn off" cell phones. Which itself is weird, 'cause I can leave mine on and put it in airplane mode, right?

Re:So if I leave wifi on?

[tophermeyer]

'cause I don't ever hear flight attendants telling people to disable their wifi (or bluetooth, etc.). Just to "turn off" cell phones. Which itself is weird, 'cause I can leave mine on and put it in airplane mode, right?

Every time I fly I hear the flight attendants tell us to power down the device completely, they usually specify that airplane mode is not ok. I've always assumed this was because they have no way if knowing of anyone actually put the thing into airplane mode or not.

Of course I don't know that that has anything to do with wireless transmission interference. They might just do it to make sure people aren't distracted by their electronic gadgets and actually listen the safety briefing.

Re:So if I leave wifi on?

[ktappe]

Every time I fly I hear the flight attendants tell us to power down the device completely, they usually specify that airplane mode is not ok. I've always assumed this was because they have no way if knowing of anyone actually put the thing into airplane mode or not.

I fly frequently on various airlines and have never heard "Airplane mode is not OK" or even any reference to "Airplane mode" at all. What airline do you fly?

Re:So if I leave wifi on?

[Richard_at_work]

Flying from Heathrow to Johannesburg on British Airways, the stewardess explicitly said Flight Mode was not acceptable("turn the device off even if the device has a flight mode"), the device had to be off. Flying back from Johannesburg to Amsterdam on KLM, the stewardess explicitly said Flight Mode was acceptable ("turn the device off or put it into flight mode"). The outbound flight was on a 747-400 and the flight back was on a 777-200.

Re:So if I leave wifi on?

[tophermeyer]

Southwest. Maybe twice a year. Usually out of Logan (Boston, MA, United States).

Re:So if I leave wifi on?

[maxwell demon]

Actually my experience (in Europe) is that during start/landing, all electronic gadgets are disallowed, even MP3 players. Once in the sky, only active transmitters are disallowed.

Re:So if I leave wifi on?

[Kelbear]

More likely it has to do with other passengers believing a rogue cellphone might crash the plane and may complain to the flight attendant if they see another passenger using a cellphone. The other passenger has no idea if airplane mode is in use.

Rather than risking a headache of explanation or calming down snippy passengers, it's easier for the attendant to just tell everyone to turn them all off. They don't really stand to gain anything by splitting hairs over with someone over what's ok and what's not ok.

Re:So if I leave wifi on?

[Anonymous Coward]

Seems to me the flight attendants always say 'turn off ALL portable electronic devices'. Later they say 'you may now use portable electronic devices as listed in the magazine in your seatback'. And those listed things always say NO RADIOS.

Re:So if I leave wifi on?

[Andy Dodd]

Yup. This is because ILS is an old and very finicky interference-sensitive system (It basically relies on determining where within an RF "pencil beam" coming from the end of the runway you are). The concern is that leakage from just the clocks in an active device could throw off the ILS system's accuracy.

Once you're airborne, ILS doesn't matter, and the remaining navigational systems are far less interference-prone.

Re:So if I leave wifi on?

[lavagolemking]

Actually, last time I was on a plane (Airtran), they said all wifi-capable devices must also be turned off. Too bad they don't actually turn off their wifi router; they just redirect you to a page saying all wireless devices should be turned off. I guess wireless routers that broadcast within these frequencies are ok because as long as they aren't actually accomplishing anything then the radio waves coming from it magically become less dangerous or something.

Re:So if I leave wifi on?

[ubercam]

The ban on electronic devices in general is for no other reason than to force you to pay attention. Takeoffs and landings are the most critical phases of flight where the most can go wrong. They want your maximum attention during these times in case of an emergency. Yelling brace brace isn't gonna get through if everybody's got their MP3 players turned up to 11. That's why they still let you have your headphones plugged in to the in seat entertainment system, because any announcements pre-empt whatever you're doing and come over the headphones as well. They obviously want to minimize risk as much as possible, so transmitters aren't allowed the entire flight.

Not everyone listens though, myself included... I've been able to send & receive texts during take off but once we got into the clouds I lost the network, whereas a friend of mine managed to send a text in flight over Atlanta on his way to Cuba from Toronto. I've left my phone on for entire flights without realizing as well, as I'm sure thousands of others do every day. I also usually have my MP3 player on, but I do pay attention to what's going on around me. A family friend owns a Cessna 152 float plane and he rigged up a system to use his cell phone over his headset, but when the phone's in use, he says the instruments go wacky. Unfortunately I didn't see it in action.

Re:So if I leave wifi on?

[Dunbal]

I have heard it once, a few years ago. I forget which airline, but I usually fly American or Continental.

Re:So if I leave wifi on?

[Anonymous Coward]

Been on 8 Delta flights in the past 3 months... heard "turn off completely" before takeoff (and sometimes landing) every time. Of course, the last leg, I forgot to even enable airplane mode. And we didn't crash... guess they weren't using Honeywell.

Re:So if I leave wifi on?

[Ares]

Delta MSP->LAS two weeks ago.

Re:So if I leave wifi on?

[Anonymous Coward]

That's the way it is in the US, too. I'll generally just put my phone into airplane mode and then stuff it in my pocket instead of fully powering it down.

- AC because I don't want put on the no-fly list

Re:So if I leave wifi on?

[bws111]

Or maybe they actually put the plane through a certification process, and know that that particular router does not cause interference with the rest of the plane.

Re:So if I leave wifi on?

[acohen1]

I've heard it every which way, and I frequently fly domestic US flights for work. At some point within the past 2 years it was very common to hear that cell-phones must be off completely and no, airplane mode is not ok. I believe that was usually on US Airways. More recently, they say airplane mode is ok, but everything must still be powered off during take-off and landing. I'm usually surrounded by people with smartphones that don't bother to shut them off and just put them in airplane mode anyway. I've also been on a handful of flights that had an in-flight Wi-Fi hotspot. I've flown on United, US air, Delta, Continental, and Southwest within the past 6 months.

Re:So if I leave wifi on?

[gstrickler]

The Tao of math: The numbers you can count are not the real numbers.

Nor are they imaginary numbers.

Re:So if I leave wifi on?

[mjwx]

So if I open up my laptop and start using it, it starts seeking wifi signals. Is this enough to interfere with the plane?

The navigation systems, yes.

I don't know about you, but I like flying in a straight line to my destination.

'cause I don't ever hear flight attendants telling people to disable their wifi (or bluetooth, etc.). Just to "turn off" cell phones. Which itself is weird, 'cause I can leave mine on and put it in airplane mode, right?

You must be deaf then. From Thai, Singapore air, Cathay Pacific, QANTAS, Air Asia and Malaysian Airlines (they all seem to follow the same script)

Please turn off all mobile telephones, portable radios, radio controlled toys, portable computers and any other radio transmitter.

After that they tell you which devices may be used in flight.

Re:So if I leave wifi on?

[Toe, The]

You must be deaf then. From Thai, Singapore air, Cathay Pacific, QANTAS, Air Asia and Malaysian Airlines (they all seem to follow the same script)

Nope. In the past couple of years, I've flown US Air, Delta, Air France, AirTran, and Spirit. And some others I think. They all said wildly different things, even on the same airline but different flights.

Most said to turn off electronics during takeoff and to keep phones off for the duration. None ever mentioned transmitters or any words like that.

Radar about to be "jammed"

[Mr. Maestro]

"Raspberry. There's only one man who would dare give me the raspberry: Lone Star!"

This is a non-story

[gad_zuki!]

Not only is it for one specific module, its only at elevated power levels, not typical power levels. Lets watch the corporate media fuck this up and turn into a scare tactic to show more ads to morons.

Boeing, meanwhile, says: "Current testing by Boeing and Honeywell has determined that blanking may occur when a DU is subjected to testing procedures specified by the FAA requirements (AC-20-164) during installations of Wi-Fi systems on the airplane. Based on testing that has been conducted, Boeing and Honeywell have concluded that actual EMI levels experienced during normal operation of typical passenger Wi-Fi systems would not cause any blanking of the Phase 3 DU. This issue does not exist with the Phase 1 or 2 DU's."
Honeywell says that, during recent ground testing "at elevated power levels", the company observed a momentary blanking on the 'flat panel' liquid crystal displays that it developed and pioneered for Boeing.
"The screens reappeared well within Boeing's specified recovery time frame. The screens have not blanked in flight and are not a safety of flight issue. Honeywell is working to ensure the problem is addressed and fixed and that our technology will continue to exceed specifications," says Honeywell.

http://www.flightglobal.com/articles/2011/03/10/354179/wi-fi-interference-with-honeywell-avionics-prompts-boeing.html

Re:This is a non-story

[kwerle]

Wow. That earns a big FU for the editors.

Thanks for the information.

Re:This is a non-story

[vawwyakr]

This is just another example of how (inexplicably to me at least) companies want to continue fear based rules that just don't make sense. It's like the whole "don't use your cell phone near the gas pump" BS that they tried to spread for a long time. Even when tests and common sense says there's no way a cell phone would cause a spark that would ignite gas fumes unless some catastrophic (and extremely rare) occurred.

Re:This is a non-story

[guanxi]

the corporate media

Why pick on them, and not the bloggers and commenters?

Re:This is a non-story

[gad_zuki!]

Because there's a profit incentive in outrage and fear. I'm curious to see if CNN can outcrazy Fox on "ZOMG WE'RE ALL GONNA DIE ON A PLANE BECAUSE OF LAPTOPS!!"

I see bloggers as a much lesser evil and they typically have comments sections in which they can be corrected - like I just did to slashdot.

Re:This is a non-story

[Anonymous Coward]

So you are admitting it can occur (even if it is a remote probability), would you take any responsibility in the case it would occur?
Just standard corporate ass covering in the good old US of A

Re:This is a non-story

[Anonymous Coward]

People have caused static sparks getting into and out of their cars, smoking and other idiotic practices while pumping gas though.
http://www.hcdoes.org/airquality/GDF/static3.htm

There is definitely a reason to be cautious around flammable vapors.

Re:This is a non-story

[Anonymous Coward]

Because the certified media outlets have real journalists, who have a responsibility to do some fact-checking.

Re:This is a non-story

[vawwyakr]

Yes this is true, static sparks can ignite gas fumes there's no doubt there. I'm just saying my cell phone is not throwing of sparks. The 3v battery can't even overcome air resistance even in a saturated environment so it can't throw off sparks.

Re:This is a non-story

[geekoid]

except wi-fi systems can fall out of spec...assuming they where in spec tio begin with. It's not uncommon for a parts manager in China decides to use an inferior line of parts for some manufacturing.

For example, lets say you order 1000 lots of an item. Maybe lot 250-670 have a part from a different vendor...like the parts managers father in laws el-cheapo transistor manufacturer.

This exact thin cause Seagate to end up with several lots of failure from one of their HD lines in the 90s.

Re:This is a non-story

[Anonymous Coward]

The phone itself, no. But dropping the phone and having the battery fall out is a different story.

Re:This is a non-story

[DerekLyons]

The rule isn't based on the cell phone causing the spark. The rule is based on people who use cell phones tend to get back into the car, sliding themselves across the seat and charging themselves with static electricity as they do so. That *can* (and has) lead to fires.

Re:This is a non-story

[Anonymous Coward]

The rule isn't based on the cell phone causing the spark. The rule is based on people who use cell phones tend to get back into the car, sliding themselves across the seat and charging themselves with static electricity as they do so. That *can* (and has) lead to fires.

Then why not put up a sign that says, "Don't get into your car while pumping gas?" Seriously!

Re:This is a non-story

[mpe]

The rule is based on people who use cell phones tend to get back into the car, sliding themselves across the seat and charging themselves with static electricity as they do so. That *can* (and has) lead to fires.

The simple solution is pumps where you must hold down a trigger for the fuel to flow...

Re:This is a non-story

[colinnwn]

And my simple solution to defeat that bogus safety consideration is to stuff a gas cap in the pump handle lever, no matter what those silly warning signs might say. Why not start a public education campaign to train people to touch their car before touching the pump handle, and also to stand to the side of the fill tube trajectory, never directly in front of it?

Oh well

[bazmail]

Time for Honeywell Avionics and Boeing to produce an enormously expensive piece of equipment that "fixes" this. Certification forcing all planes to carry it would be a bonus.

Ok gents, quick as you can now...

Re:Oh well

[Anonymous Coward]

I see you have worked for Honeywell as well
The way they work would be funny if it wasn't so sad....

creators; death acceptable by natural cause only,

[Anonymous Coward]

mainly old age. are they pushy or what? looks like that's it for now? see you at the play-dates?

the problem: an airplane is a metal aluminum tube

[circletimessquare]

they need to build airplanes out of brick, or concrete

Time to go back to IR and Visible light.

[LWATCDR]

Hey didn't we see something about a network that works in the optical spectrum not to long ago. Seems like a good idea on an airliner.

Re:Time to go back to IR and Visible light.

[blair1q]

So how're you going to watch pr0n under a blanket when your iPad has to have a clear view of a bubble on the ceiling?

What sort of equipment is this?

[vawwyakr]

So the company just admitted that their (likely expensive) aviation equipment (displays?) are more error prone from EMI than say....my desktop pc...phone...digital watch? What sort of equipment are these people working with? Consumer electronics are bombarded by this sort of EMI constantly and I don't see any displays blanking in my office. In an airplane I would have assumed they would have to have MORE shielding because at altitude they have less shield from solar radiation which is well known for being harmful to electronics where my wifi adapter hasn't fried a single piece of electronics...yet. This still sounds like total BS to me.

Re:What sort of equipment is this?

[Anonymous Coward]

The blanking is probably a 'reset' of the computer. The computer probably detected something wrong and reset itself.

They found it and are fixing it. So the system is working. This article seems to be more scare mongering than anything. Also my computer 'blanks' all the time. But I do not notice it as it happens so much. Especially if it is switch resolutions, or crashing, or ... They noticed it because that screen is probably a single status screen and should not change. Probably a 'whoa what was that' moment.

http://mobile.slashdot.org/comments.pl?sid=2031258&cid=35442540 this has a nice link that describes what is really going on.

Re:What sort of equipment is this?

[Andy Dodd]

Actually if you look through details, it sounds like an EMI hole below that which is specified by the relevant standard was within the 2.4 GHz band.

This hole was nowhere near deep enough for a WiFi device to actually exceed the threshold, but the FAA is VERY conservative when it comes to civilian airliners - Any hole in that band = eliminate all transmitters in that band just to be sure.

Re:What sort of equipment is this?

[Anonymous Coward]

Try putting a transmitting cellphone next to a monitor or powered speakers. Consumer equipment isn't magically immune, you just don't notice the effects.

Re:What sort of equipment is this?

[MattskEE]

If you RTFA you will see that the problem occurred at elevated power levels, above what consumer level equipment normally outputs. Unlike the consumer electronics that you are in love with aviation equipment needs to be far more reliable because it is "mission critical", i.e. people's lives depend on the equipment performing correctly under a variety of circumstances. This is why they test it more stringently with elevated levels of interference which is higher than what is expected during operation.

Furthermore, as is evident from the summary alone, this has occurred during EMC testing of the aircraft, i.e. the part of the testing process which identifies problems exactly like this one so that they can be fixed before delivering the plane to customers. If you got your hands on alpha or beta versions of consumer electronics you would probably find it had bugs like that as well.

The Slashdot summary barely hypes this up, the post title is clearly exaggerated but the actual summary is pretty fair. And yet you jump up, swallow the hype whole, and comment without even reading the summary.

Re:What sort of equipment is this?

[Anonymous Coward]

Your desktop PC also isn't flying a plane with dozens of lives at stake. For instance, when my display refreshes in certain ways, I can hear a slight buzz in my speakers. That's interference from something in the graphics adapter being picked up by the audio-carrying cables inside the case. It's not a big deal, but if those cables weren't connected to a $10 speaker, and instead to, say... a navigational antenna? I wouldn't want to be in a plane that's flying towards the landing strip, plus-or-minus a few degrees.

New Expensive WI-FI coming soon?

[mattwrock]

Boeing is probably working on a "new" WI-FI system. It isn't different than the current system, but the airlines can charge a premium price for it.

Re:New Expensive WI-FI coming soon?

[cowboy76Spain]

??????

Let me ask yourself: when you are in a plane... are there, now, other WiFis to which you can connect? Not someone else's computer that is useless (unless you want to have a LAN party), but something that will give you internet access?

Even if Boeing is designing that "new" Wi-Fi that you guess, they do not need to deliver FUD to become the only operator. In fact, this only discourages Wi-Fi usage (yes they can claim later its Wi-Fi is safer, but some doubt will remain...)

Next conspiracy theory, please?

Tempest in a teapot...

[jedidiah]

I dunno. This seems like something with a terribly simple fix...

        JUST DON'T USE WIFI.

If you want networking in an aircraft, do it with wired Ethernet.

Of course this screws over all of the most hyped devices but that's life sometimes.

[Nelson] Ha Ha! [/Nelson]

Re:Tempest in a teapot...

[blair1q]

I have a better solution:

Don't fly.

Seriously. This is one reported issue. If you saw the whole list, you'd stay 10 miles from the airport at all times.

Re:Tempest in a teapot...

[gstrickler]

That's potentially worse. Not only is the cost to wire a plane outrageous, but allowing people to plug into Ethernet adds yet another way to attack or interfere with the plane's electrical system. Yes, there are ways to mitigate the problem, as evidenced by some planes having power ports and/or headphone jacks, but it's still something that would need to be carefully isolated. It also doesn't do anything to prevent a Wi-Fi device from transmitting (either normal polling for an available network or maliciously transmitting packets), which means you have to defend the plane against both wired and wireless attacks.

Re:Tempest in a teapot...

[Anonymous Coward]

So I can take out a civil aircraft using a domestic wifi sender and a wave guide made out of say, a couple of bake bean tins - cool

Re:Tempest in a teapot...

[colinnwn]

Because that would add a lot of weight, and wiring to maintain to airworthiness standards. Instead, why doesn't the WiFi unit in the plane have a self test feature like many avionics, that can tell when it is broadcasting out of spec and shut it down?

Re:Tempest in a teapot...

[Anonymous Coward]

And yet flying is still the safest form of transport per mile. Since most flying accidents occur around take-off or landing, it may not be the safest for short journey, but certainly is for long journeys.

Re:the problem: an airplane is a metal aluminum tu

[xMrFishx]

Well when the engines turn off, they effectively fly like they're made out of either.

Jeez

[Anonymous Coward]

Talk about Pwn2Own!

Conflict of interest?

[BenJeremy]

Yes, because we know Boeing and Honeywell have no interest in keeping WiFi on a short, monetized leash in aircraft...

http://www.boeing.com/Features/2010/04/bds_feat_BBSN_031210.html

Re:the problem: an airplane is a metal aluminum tu

[circletimessquare]

i made a dumb joke, but heck, if they can build boats out of concrete

http://en.wikipedia.org/wiki/Concrete_ship

i therefore desire some insane mofo to try to build an airplane out of concrete

Not something to be proud of

[Quiet_Desperation]

I can make a Tesla coil out of $50 of junk surplus parts and destroy a roomful of the highest end electronic equipment in the world. Hell, a simple spark gap in the right place can cause a world of hurt.

RF energy doesn't give a fuck where you bought something.

You cannot fully shield a device that is specifically designed to receive external signals. In aerospace there's guys who do nothing but electromagnetic compatibility engineering, and not all the threats are external. Sometimes the third side lobe of your strike radar reflects off a rib in the fuselage and the seventh harmonic frequency takes out your very sensitive radar altimeter during initial power up tests.

Re:Not something to be proud of

[blair1q]

You cannot fully shield a device that is specifically designed to receive external signals.

But if you don't design it to reject signals outside the band you intend to receive, you've failed to design it at all.

Re:Not something to be proud of

[thegarbz]

Define reject. In decibels. At a specific frequency.

To get a feeling for this you should open up some RF gear, where part of the signal propegation and rejection strategy involves using PCBs made of teflon half a mm thick.

No rejection band is infinite, regardless of what Elec101 teaches you.

Re:Not something to be proud of

[kju]

I can make a Tesla coil out of $50 of junk surplus parts and destroy a roomful of the highest end electronic equipment in the world.

Nonsense. Operating a Tesla coil does not harm other electronics. I know because we have one in our hackerspace. It is operated occasionally and beside some noise we had recently in a AV recording and bad odor in the air it has no bad effects.

Re:Not something to be proud of

[Anonymous Coward]

However, you can generally shield one well enough. There are things on the ground that require practical immunity from RF interference. An electric wheelchair, for instance, is dangerous to the rider if it gets out of control (gee this cliff looks nice..). Devices like this are tested like crazy to avoid the legal liability that comes with somebody's cellphone causing it to drive into the river. Now, my question is this: can airplanes be shielded that well? At the surface, the principle certainly seems the same (shield the hell out of it).

In any event, how is it that airplanes are not affected by things like tv broadcasts, amateur radio, satellites, etc. which are blasting radiowaves at similar frequencies (see: http://www.ntia.doc.gov/osmhome/allochrt.pdf)?

Re:Not something to be proud of

[Quiet_Desperation]

Most things are designed that way, but you can get harmonics and intermod product that land smack in the middle of your window. Sometimes the interference is just a blob of wideband noise across your passband.

Re:Not something to be proud of

[Quiet_Desperation]

We built one in high school that took out the two televisions in our lab.

Re:Not something to be proud of

[Quiet_Desperation]

True, but a wheelchair is a closed system. It doesn't require external I/O to function. Ports for charging the battery or downloading software updates (if it's a really fancy chair) can have shielded covers.

I know people who have done electromagnetic compatibility work. It's a specialization. It is *not* easy, especially in a signal rich environment like an aircraft. It takes a lot of work to keep a plane's systems from interfering with *themselves*. I hear it can be quite maddening at times, especially when they update older aircraft with systems that didn't exist when the plane was originally designed.

In any event, how is it that airplanes are not affected by things like tv broadcasts, amateur radio, satellites, etc. which are blasting radiowaves at similar frequencies (see: http://www.ntia.doc.gov/osmhome/allochrt.pdf)?

Those are known threats, I would guess. Wi-fi is still relatively new. Hey, so far there seems to only be this one example, but flight is a hypercautious industry. Personally, even if I'm flying for work, I see the flight as a time to relax. I never got these guys feverishly working away on their laptop throughout the flight.

Re:Not something to be proud of

[Quiet_Desperation]

Actually, my first filter class talked extensively about how you also have to design the reject band in addition to the passband because you only get so much rejection. In the strike radar example I mentioned, the main signal was tens of kilowatts, maybe higher. Even harmonics on side lobes can carry enough energy to damage the sensitive components at many receiver inputs.

Re:Not something to be proud of

[blair1q]

Define reject. In decibels. At a specific frequency.

Use of the word "bandwidth" implies 3 dB attenuation at either end of the width of the band. Rolloff beyond that will depend on your choice of filter.

Parasitics are an issue, but Wi-fi and cell-phones aren't operating at exotic frequencies above 10 GHz, so "infinite" is an unnecessary invocation in the requirements at this point. At the low-end, nothing smaller than a power grid or solar flare can put out enough signal to make a dent in overwhelmng the filtering and shielding.

As for my feeling for this, I'm going to be knuckles-deep in prickly little circuit boards in about 8 minutes.

Re:Not something to be proud of

[blair1q]

From reading TFA, I would guess they're doing a test that sweeps a mongo peak up and down the wi-fi frequency band as a worst-case scenario, with the transmitting antenna strapped to the cabling of the box being tested. It's be interesting to see if there's any way they could replicate it using any commercial wi-fi device, locked to the channel they think has the problem, sitting in the navigator's flight bag (because his own iPhone would be the most pessimal culprit).

Re:Not something to be proud of

[tpholland]

RF energy doesn't give a fuck where you bought something.

Than is my new favourite quote. Genius!.

Re:Not something to be proud of

[Anonymous Coward]

Due to lack of funding, your budget proposal for $50 to construct a low grade Tesla coil destructo device has been denied.

Procurement has substituted this $0.01 plastic cup and written directions to the nearest water faucet.

Thank you.

Re:Not something to be proud of

[Hognoxious]

how is it that airplanes are not affected by things like tv broadcasts, amateur radio, satellites, etc. which are blasting radiowaves at similar frequencies

I'd guess it's something to do with the inverse square law, given that those things are a little bit further away than something that's actually inside the plane.

Just an FYI

[Anonymous Coward]

There's only one "w" in "flawed". There are no English words that contain "ww".

Re:Just an FYI

[Buggz]

There are no English words that contain "ww".

Aww. :(

Re:Just an FYI

[SecurityGuy]

Really? grep ww /usr/share/dict/words has 87, a good portion of which appear to be unquestionably real words.

Re:Just an FYI

[tomhuxley]

flawwed isn't a word in English but there ARE English words that have the "ww" combo, that combination was fairly rare and you often tend to see them separated into word phrases but glowworm, powwow, and arrowwood are real words in English.

But there is one word which is quite common -- if you consider acronyms to be "real" words (and only Scrabble seems to think they aren't) -- then WWW is probably the most common.

Re:Just an FYI

[1729]

There are no English words that contain "ww".

Yellowwood:

http://en.wikipedia.org/wiki/Cladrastis

Re:Just an FYI

[Wyatt Earp]

Powwow isn't an English word, its a Narragansett word.

Re:Just an FYI

[MozeeToby]

By that logic half the words in the average English speaker's vocabulary aren't "English words".

Re:Just an FYI

[Wyatt Earp]

You are correct, the poster I replied to said powwow are real English words.

Re:Just an FYI

[not flu]

Shawwal being the only non-compound word of the lot. I had never heard of AC's rule of thumb but I'd say it holds true.

Re:Just an FYI

[tomhuxley]

This is so off-topic it isn't funny, but powwow is by any standard a real English word.

You are right that it is derived from a Narragansett word (which was itself derived from an Algonquian term for a spiritual head of a tribe) but it has been used in English as a synonym for meeting or gathering since 1812. Even before that, the word was first used in English as a general term for native gatherings as far back at the 1600s.

Would you say that canoe or barbecue are not real English words? Both come originally from Arawakan.

Completely inaccurate headline

[GooberToo]

Headline should read, Poorly Designed Aviation equipment Suffer interference From WIFI, with the body reading, "...when WIFI transmits at levels far in excess of consumer equipment."

There isn't a story here.

Phone use in airplanes has always been about economics and excessive use of scarce ground resources.

More importantly

[maweki]

If Wi-fi interferes with the board systems, doesn't this (more importantly) mean, that the board systems interfere with the wi-fi? What am I supposed to do during a long flight? Angry-Birds instead of CounterStrike? I don't think so.

So how much excess transmitter power?

[AbrasiveCat]

I wonder if it took a 1 or 2 kw WiFi transmitter to cause this problem? More likely 1 or 2 watts, but the link did say existing legal power did not cause an issue. Then I wonder how far the transmitter was from the display unit? Maybe this just mean the air crew should not use over powered WiFi devices while playing video games in the cockpit?

Re:So how much excess transmitter power?

[Anonymous Coward]

1-2 kW - probably not.

You can hit MIL-STD-461E RS103 levels with well less than this (but well above 2W - probably in the lower hundreds of watts).

The FAA standards are probably well below 461E levels but well above what any wifi device could generate. The unit failed the standard within the WiFi band - the FAA is being conservative here.

Next on TSA theatre!

[JustAnotherIdiot]

TSA to search your pockets and confiscate any electrical devices.

Re:Next on TSA theatre!

[couchslug]

"TSA to search your pockets and confiscate any electrical devices."

Next on terrorist theater, pack proper electronics in a notebook to spoof avionics test equipment and make landings impactful.

FUD?

[Anonymous Coward]

I wonder how much of this are the OEMS making the case that only their proprietary/exorbitant in-flight wifi solutions are safe enough to install.

Terrorist EE Applications are rising

[PolygamousRanchKid]

In other news, university officials have noticed a sharp increase in the number of terrorists applying for admission to EE degree programs. Until now, terrorists have traditionally favored chemistry and chemical engineering programs. Chem E applications have dropped sharply.

Chem E prof: "I really don't understand it. We still have a great program, Although it was strange: all that these students seemed interested in, were exothermic reactions.

EE prof: "I really don't understand it. Who would study EE, when the country you come from doesn't even have electricity? Although it is strange: all these students seem interested in, is building high power transmitters at frequencies where such power is not allowed by the FCC. Maybe they don't have an FCC where they come from?

Sounds more like a design flaw

[grapeape]

This really sounds like a failed design where blame should go to Boeing rather than the IEEE standard.

Didn't mythbusters address this once?

[mark-t]

And didn't they conclude that portable consumer devices that are operating within normal parameters could not interfere with the plane or its operation?

Does this mean that the Mythbusters were wrong?

Re:Didn't mythbusters address this once?

[vawwyakr]

Mythbusters are never wrong! In point of fact though they may not have used this particular display and I believe they were testing cell phones and not wifi.

Re:Didn't mythbusters address this once?

[demonbug]

Mythbusters are never wrong! In point of fact though they may not have used this particular display and I believe they were testing cell phones and not wifi.

That, and the article specifically states that they were testing with equipment operating well out of the normal operating range for consumer devices (presumably significantly higher power output).

Re:Didn't mythbusters address this once?

[Darinbob]

No. Read the article, and not the misleading idiotic slashdot headline!

Re:the problem: an airplane is a metal aluminum tu

[xMrFishx]

On the thought of making planes out of something strong and non-metal, I wonder what the feasibility of carbon fiber (and carbon nano-tubes?) is. I admit I know nothing about these materials besides their press-release descriptions.

Re:the problem: an airplane is a metal aluminum tu

[Anonymous Coward]

an airplane is a metal aluminum tube

As opposed to a paper aluminum tube?

Hooray!

[rilister]

...and I say thank all that's holy for that. Anything that keeps airplanes as the one place that I'm not going to be bothered by "CAN YOU HEAR ME NOW?" or disturbingly personal/intimate conversations of total strangers is entirely welcome to me. Give me one refuge from connectivity, please, just one.

yes

[circletimessquare]

and as opposed to a transparent aluminum tube ;-)

cellphone and speakers

[hort_wort]

I've never understood why people call this a myth. Whenever I'm sitting near speakers and my cell phone decides to check in with the tower, I hear a distinct beeping noise. If I can *hear* the effect of a signal, why do people think that a switch can't flip because of it? I don't want to die in a fireball of doom because you wanted to tweet that the guy next to you on the plane just farted.

It's all about weight

[Anonymous Coward]

It's not that there aren't solutions to EMI problems that could be implemented, it's that they add weight to an aircraft. For commercial aircraft this is a no-no. Airline company's would rather save money on gas, so Boeing and Honywell comply by designing equipment with little to no margin where it's absolutely not needed.

oh yeah, carbon fiber is amazing

[circletimessquare]

they already use it

http://www.google.com/search?q=carbon+fiber+aircraft

but i'm talking about building an airplane out of something absolutely insane, impractical and impossible at face value. like cast iron. or concrete

Re:oh yeah, carbon fiber is amazing

[xMrFishx]

I guess if you want impractical, you could make a plane out of a non-newtonian fluid. I can imagine making a plane out of custard. It'd stay together if you flew it fast enough. All you need is a mach-1 capable plane-shaped custard mould and one of those refueling planes full of the stuff.

Re:oh yeah, carbon fiber is amazing

[circletimessquare]

LOL. the moment you stop moving... slurp

Wifi does not interfere with "Airplanes".

[Belial6]

So the title is wrong. It should read. "It is possible to build an airplane that can pick up WiFi signals". This isn't a case of Wifi being able to interfere with "Airplanes" as in the generic term "Airplanes". This is a case of one system that has never been shipped being faulty, and picking up Wifi signals. This is Wifi "being able to interfere with planes" as much as "loud chanting can interfere with planes". No doubt Honeywell could build one of those too. Heck, I'm sure if they put their mind to it, they could build an airplane that would blink the screen when someone ugly got on board.

Re:Wifi does not interfere with "Airplanes".

[Darinbob]

Slashdot: Misleading headlines for nerds who don't read

Re:Wifi does not interfere with "Airplanes".

[Belial6]

Fox News for Nerds?

Totally Appropriate PA moment

[Azureflare]

http://www.penny-arcade.com/comic/2006/10/30/

Re:Totally Appropriate PA moment

[Vyse of Arcadia]

Mod parent up! I clicked this article for the sole purpose of posting that Penny Arcade comic.

Here's the fix...

[herojig]

Everyone install SBSettings and with one swipe press the Airplane icon during preflight. Done.

Re:the problem: an airplane is a metal aluminum tu

[Anonymous Coward]

How about Carbon Fibre composites as used in fighter aircraft? IIRC the Typhoon is something like 80% composites?

Is there a service life issue with using those materials, or are they just too expensive at the moment? If the latter, would the problem self correct with economies of scale?

this makes me question

[nimbius]

whether boeing has a stake in aeronautical wireless technology. there is already a company that provides in flight wireless....i wonder how they get around the known issues.

Now which is it?

[Anonymous Coward]

Wi-Fi or "wireless broad band"? Yes Virginia, they're not necessarily the same. Now, which is it?

Solution: Read Slashdot!!

[Anonymous Coward]

Wow, it's amazing that a team of electrical engineers working at two of the most technologically advanced aircraft equipment manufacturers failed to consider all of the simple fixes being proposed by the brilliant minds posting here on slashdot. "Faraday cage!", "More shielding!", "Transmission lines!" I'm pretty sure the engineers haven't even considered these ideas that any sophomore EE student is aware of. "But I read the article!". Did you read the Design Verification Test report? Do you have any specific data about exactly what the problem is or what caused it? Like EIRP, channel, distance? What step of FAA procedure AC-20-164 that the failure occurred at? Do you know what anomalous signals were present on the display's circuit board and at what test points and why those might differ from other phases of this unit? (DU Phases 1, 2, and 4 are not affected, phase 3 is: why?)

Short answer to Boeing

[erroneus]

DESIGN YOUR CRAP RIGHT!! Nothing as important and critical as an aircraft should be designed in such a way that it is vulnerable to something as simple as a WiFi signal.

This finding is not a condemnation of WiFi on planes. It is a condemnation of the planes themselves!! And of course now that "the terrorists" (which is every living, breathing human on the planet as far as the US Government is concerned) know about it, we're in for even more nonsense at the airports.

Boeing, fix your crap or we'll start buying from Airbus.

Re:the problem: an airplane is a metal aluminum tu

[demonbug]

i made a dumb joke, but heck, if they can build boats out of concrete

http://en.wikipedia.org/wiki/Concrete_ship

i therefore desire some insane mofo to try to build an airplane out of concrete

Concrete boats do sound sort of strange at first pass, but if you think about it, concrete is quite a bit less dense than, say, steel - and we've been making boats of of steel for a long time. At the same time, you don't really see very many boats made out of concrete (despite the relative inexpensiveness of concrete) because concrete just isn't a very good material for boats - very low tensile strength, bulky, etc.

I'm sure one could make a plane out of concrete, it just wouldn't be practical. In college we had a very competitive concrete boat (concrete canoe?) team. While these were made with "concrete", it wasn't your normal cement and aggregate mix - it was cement, low-density fillers (sort of like tiny ping-pong balls), high-strength oriented fibers, etc. Expensive (for concrete), lightweight, relatively strong, and when coated with a polymer film (plastic) made a very fast boat. I'm sure you could use the same material to make an aircraft fuselage (and probably at least parts of wings), but it just wouldn't offer any advantages over other materials that are lighter and stronger, and it would offer significant disadvantages (still relatively weak tensile strength being a biggie for an aircraft I would imagine).

Is this a GPS problem?

[CodeShark]

Having just read a very interesting (read: somewhat frightening in terms of implications) article about GPS jammers, I am wondering if it's the wifi signal or the fact that a lot of wifi devices (read: smartphonee) now have GPS apps, etc. which would very definitely be competing for signal/timing/ etc. that ARE in use in aircraft systems... Thoughts from the Slashdot technorati please?

Re:Is this a GPS problem?

[Andy Dodd]

Nope. If you read the articles in more detail, what happened is the unit failed EMI testing. The end reaction to the failure indicates the hole probably occurred somewhere around 2.4 GHz - however at power levels WELL above what any consumer wifi device is capable of producing (But below that of the standard).

But the FAA is VERY conservative, so a radiated susceptibility hole in the band for a device = kill all emitters in that band, even weak ones, if that device is in use.

Re:the problem: an airplane is a metal aluminum tu

[circletimessquare]

right. but your problem is you are trying to make sense. i am not proposing something someone would do for any rational reason other than fancy. or, as a learning lesson. the concrete canoe competition you cite has no valid real world value save teaching, right? i am saying build an airplane out of concrete, just for the sake of trying, and therefore learning

Are you new here?

[Anonymous Coward]

Are you new here, or something? That's all Slashdot has been from the start: ignorant nerds spouting off comments about subjects they know nothing about. Opinions with stupid conclusions are rated Informative, countering them with facts are labelled Troll. See any Apple topic from the start through to, oh, maybe 3 years ago.

As The Minutemen once wrote, the roar of the masses could be farts.

What terrorists?

[Anonymous Coward]

What terrorists?

But you know exactly where this is headed

[Lead Butthead]

Airlines and plane manufacturers will complain endlessly about how expensive it would be to retrofit all the planes that's in service already, and how much more expensive it would've made the airplanes and "hurt competitiveness" or "impact job growth." The government would cave in and instead of mandating all plane electronics must be properly shielded against something as common as WiFi, they would simply pass a law prohibiting use of WiFi on planes and then promptly declare all flights are now safe...

They should probably be very quiet about this.

[Anonymous Coward]

Since 2006 or so no new equipment may be used in the EU if it can't handle radiation from CE-marked equipment or if it itself is malicious to CE-marked equipment. There are few exceptions from the rule (military equipment being one), there are also exception for old equipment (manufactured before 200x)

Re:the problem: an airplane is a metal aluminum tu

[Anonymous Coward]

they need to build airplanes out of brick, or concrete

That'll never fly.

Re:the problem: an airplane is a metal aluminum tu

[Anonymous Coward]

A lot of newer airplanes are composite. The 787 contains approximately 35 short tons of carbon fiber reinforced plastic (CFRP), made with 23 tons of carbon fiber. Aluminum is used on wing and tail leading edges, titanium used mainly on engines and fasteners, with steel used in various places (http://en.wikipedia.org/wiki/Boeing_787_Dreamliner)

Re:the problem: an airplane is a metal aluminum tu

[SleazyRidr]

Nah, the highways aren't wide enough.

WiFi on the plane!

[Anonymous Coward]

Its a f*cking airplane! Cat5 will do, no need for wifi...

so...

[Anonymous Coward]

So is my sneeze :P

Re:the problem: an airplane is a metal aluminum tu

[circletimessquare]

baDUMP *ching*

Very specific EMI Issue

[Anonymous Coward]

This has been a known issue for over a year and was brought up at the AMC (Avionics maintenance conference) in PHX in April 2010.

The equipment in question is the Honeywell Phase III primary flight display on 737 and 777 A/C. It's Phase III because Phase I & II became obsolete once their LCDs were no longer repairable or fixable. Aircell, the maker of the wifi system, created and tested their system against the Phase I & II units and passed before Phase III was put into production. Early speculation was that the blanking was caused by a certain operators wifi system placement and as such was not experienced by other operators who chose to locate the system elsewhere.