Slashdot Mirror
Personal Electronics May Indeed Disrupt Avionics
mattrwilliams writes "There is a growing body of anecdotal evidence that points to personal electronics being a real issue on board planes. Dave Carson of Boeing, the co-chair of a federal advisory committee that investigated the problem of electronic interference from portable devices, says that PEDs radiate signals that can hit and disrupt highly sensitive electronic sensors hidden in the plane's passenger area, including those for an instrument landing system used in bad weather."
There is a growing body of anecdotal evidence
Need I say more?
If planes switched to fiber optics and got rid of copper wiring I'm sure that would reduce the likelihood of interference. I can hardly wait for the day people will be able to use their cell phones on those long haul flights.
"You'll get nothing, and you'll like it!"
A couple of coats of lead based paint will take care of that.
"A person is smart. People are dumb, panicky dangerous animals and you know it." - K
These planes can take direct lightning hits but the sensors cant handle a cell signal that's going to be there weather the phone is off or not?
does not compute
Brrrrrrr.....Dut Dut Dut Dut Dut....brrrrrrr
What a great way to trash a recording.
I had always heard that the real reason they make you turn off electronic devices is so that you listen fully to any instructions you are given. Why else would they make me turn off my wi-fi only Kindle?
I was told by people on the internet that this cannot possibly happen, so this expert from an actual aircraft manufacturer must be wrong.
This is the first page of the story, summary links to page 2.
I can see the fnords!
ILS receiver antennas aren't "hidden inside the passenger compartment".
They're "attached to the outside of the friggin airframe".
Any story that gets the details that wrong, that fast, receives no credence at all. And if airplanes are having this much trouble with my 2mw iPad, what the *hell* are they doing about getting hit by 2GW of lightning?
(And don't tell me "Faraday cage"; that protects the occupants, but not necessarily the things connected to antennas outside the cage.)
As i was told in mid 90 by my electromagnetism teacher, the problem is not the miriad of (then) walkmans and cd player used in the plane. Those are more or less certified for electromagnetic compatibility. The problem are the crappy chinese electronics that don't pass any test and the one in a million "certified" hardware that is faulty. So, do you prefer listen your music and risk your life in an emergency situation or forbid them all just in case?
And speaking of statistics, in this case "anecdotal evidence" can cause the death of 200+ people...
now that's just good science right there
Seriously? "Anectdotal"?
This isn't the Middle Ages here, and there are lives at stake. If someone seriously believes there is a safety issue here, there must be scientific studies to show what is going on one way or another.
I cannot see how the planes can get FAA certification if this is true. either the tests are not appropriate. or they are not being conducted properly. Which is it? Enquiring minds want to know!
Sent from my ASR33 using ASCII
1. Personal electronics are safe, this is just BS.
2. Personal electronics are not safe, thus if a terrorist wants to crash a plane, all they need to do is use an iPad.
I mean TSA takes away bottled water, if the iPad was really threat, why don't they take those too? Better resale value than the bottled water.
=================
Unix is very user friendly, it's just picky about who its friends are.
There is a growing body of anecdotal evidence
Need I say more?
Actually, yes. How about something regarding consequences? Say 100+ people in a fragile machine, surround by flammable liquids, moving at a high rate of speed and doing so with limited to no visibility outside the machine having a "mishap" because someone had to check twitter? There are some activities where an excess of caution is warranted, personally I believe that needing to use an ***instrument landing system because of bad weather*** is one such activity.
The real world is not as simple as your freshman physics/engineering class would have you think.
So they're telling us that they're going to leave the security of landing an airplane to the passengers knowing how to turn their "PEDs" off? My mom just bought an iPad - I suspect she doesn't know how to *really* turn it off. Same thing for all those iPhone/Blackberry/smartphone users.
If it *REALLY* was such a problem, then they should confiscate the PEDs and give them to us when the flight lands.
I call bullshit. These instruments are TEMPEST shielded to such a degree it's ridiculous. Personal devices also don't emit with enough power (unless modified) to affect anything further than a couple of feet away from them.
"Growing old is inevitable; growing up is optional."
I had always been suspicious of the reality of small electronics and avionics interference, but now I have some first hand experience--I fly a small airplane (a Decathlon). Granted, it has much different RF characteristics than a large airliner. Like most airplanes, it is equipped with a transponder that encodes the airplane's altitude and transmits it when the air traffic control radar paints the airplane. Sometimes when my iPhone is turned on in the airplane, the altitude reported by my transponder varies wildly by several thousands of feet, and air traffic control tells me they are getting spurious signals. One day when this was happening, I thought ah heck and I turn off the phone, and the transponder settled down. I turned it back on, and the transponder started going wonky again. I've reproduced this on a few different days and most days with no issues with the phone turned on. I'd say it's 20% bad/80% good. I haven't figured out what conditions cause this to happen or not--could be poor equipment installation. Anyone else with actual experience of something like this happening?
Anecdotal evidence is the best kind of evidence so I've been told.
As an engineer who designs and integrates RF systems every day, all day, I have two impressions. And as a systems engineer, I'll describe them in terms of the two elements of risk: probability and impact.
FTFA: "In other events described in the report, a clock spun backwards and a GPS in cabin read incorrectly while two laptops were being used nearby."
First: Crap like that ain't supposed to happen. An airplane designed and built to standards for commercial passenger service must meet standards for electromagnetic susceptibility, interference tolerance, workmanship, etc. It's not the passengers' fault that things like that happen. Nor is it the direct fault of the manufacturer of the electronics that passengers carry. If something is that mission critical, and the cost of failure is measured in human lives, then engineers, inspectors, regulators, and operations crew damn well better make sure the likelihood of failure is as close to zero as can be.
Second: I know damn well that grounding and shielding is one of the most difficult aspects of any high-frequency electronics system. It's difficult to design, grounding and shielding design rules aren't generally taught as part of undergraduate EE curriculum (much less Aeromechanical, CS, etc.), and the manufacturing techniques are prone to failure and not easy to inspect and test. Therefore, statistically, a passenger that travels one or two times a year is likely to board a plane with a design flaw or manufacturing/maintenance flaw at some point in their lifetime. This doesn't mean they're going to notice it, or even have any effect on the flight, much less cause an emergency by forgetting a powered-up iPhone in their carryon. But the likelihood of failure will never be zero unless the passenger obeys the rules and turns off their devices.
So, turn your shit off when so instructed.
And consumer electronics designers: please give the consumer a switch that allows them to turn their shit off... not standby, but OFF.
I can see the fnords!
To me this just means that Boeing engineers need to do a better job of shielding their sensors. The world has advanced, people have such devices and flights are getting longer. I dont want to use/pay for the crappy entertainment system on the plane. I want to use my own. I understand that this might not be the priority for them right now, but it needs to happen sometime soon.
We spend hundreds of millions to keep me from bringing a bottle of water on a plane, but we can't manage to get protection from terrorist magic rays that will take down a plane just like in the movies? I thought all of these guys went to the Jack Bauer school of counter terrorism.
On a recent Delta flight from Orlando to Minneapolis, I had the pleasure to sit next to a Delta employee on the same trip. He didn't even bother turning his iPhone on airplane mode.. in fact he was checking his email during takeoff and landing.
I kept hoping and waiting for his phone to ring during flight.
Boeing simply wants to divert attention from their own design/maintenance problems they've been having recently that have caused serious accidents. But I thought the main source of accidents/mishaps is really pilots. And PEDs have caused zero accidents.
Like these: http://www.jeppesen.com/main/corporate/microsites/jeppesen-mobile-tc/
"The authorization process noted by the FAA allows the operator to use iPad and the Jeppesen Mobile TC App as the sole reference for electronic charts, even during taxi, takeoff and landing. "
They've been lying about this for years. Let's use a little common sense to figure out the truth, here:
First, probably 90% of the people on every plane have one or more devices. Laptops, game devices, tablets, phones, and so on.
Second, there are several thousand flights in the US every single day.
Third, just because they say "turn off your devices" doesn't mean people do. In fact, I know people who intentionally don't turn their devices off, just as a personal point of spite.
Fourth, if these were a problem, planes would be fucking falling out of the sky. If you figure there are 300,000 to 500,000 people flying every single day, we should be seeing unexplained major airline catastrophes all the damn time.
Fifth - and finally - if this was even remotely a problem, they wouldn't have allowed devices all these years. In fact, if it was anything other than PROVEN to be safe, they wouldn't allow them. They would confiscate devices on entry and turn them off themselves or store them in some sort of Faraday cage kind of thing until you de-board.
Mythbusters busted this one I'm sure. So it must be safe........
Mythbusters already busted this myth.
TFS is not summarizing TFA. Is it also because it links to TFA's page 2?
Proper link: http://abcnews.go.com/Blotter/safe-cellphone-plane/story?id=13791569
Proper excerpt:
Asked if a cellphone's signal could really be that powerful, Carson said, "It is when it goes in the right place at the right time."
To prove his point, Carson took ABC News inside Boeing's electronic test chamber in Seattle, where engineers demonstrated the hidden signals from several electronic devices that were well over what Boeing considers the acceptable limit for aircraft equipment. A Blackberry and an iPhone were both over the limit, but the worst offender was an iPad. There are still doubters, including ABC News's own aviation expert, John Nance.
"There is a lot of anecdotal evidence out there, but it's not evidence at all," said Nance, a former Air Force and commercial pilot. "It's pilots, like myself, who thought they saw something but they couldn't pin it to anything in particular. And those stories are not rampant enough, considering 32,000 flights a day over the U.S., to be convincing."
Ever heard of shielding, Boeing? Seriously.
If this were actually that bad of a threat, don't you think TSA/DHS would have adjusted their policies regarding PEDs onboard? Give me a break. Chances are they're crying wolf so they can try and secure a few billion in funding to upgrade all of their aircraft wiring and shielding under the guise of "homeland security", so taxpayers can somehow pay for it instead of the "poor starving" airlines.
Oh, and pay no attention to the terrorists lurking here taking notes (the real terrorists I mean, not your next-door-neighbors Grandmother caught trying to "smuggle" her Sams Club sized shampoo bottle on board). God forbid they find out an iPod is just as effective as a box cutter. Yet another reason I call BS on all this, as if had ANY semblance of truth, it certainly wouldn't be unclassified.
If there is or may be a problem, then develop a standard for both the electronic device maker and the navigation system maker can work with. I'm sick and tired of airplane makers saying that everyone must shut down all possible electronic devices or the airplane will crash into the ocean Does that include pace makers? How about artificial limbs that are electrically powered? Navigation systems should be defined to work with a given amount of noise on various frequency bands. It is not reasonable in today's world to design a system that assumes that the only RF transmitter for 100 miles around is the proper transmitter. Think of what a terrorist could do if they find such a vulnerability that can let them remotely down an airplane.
Conversely, electronic device makers must start shielding their equipment and start certifying that they meet this same standard. I've seen too many devices that have the EMF of a telsa coil and wipe out any other wireless device within 30 feet. One device was not even a wireless device. It was a street light that ran on 2.4Ghz, and wiped out WiFi whenever it was on.
Makes perfect sense; the couple microwatts of radiated EMI from my device is TOTALLY going to cause havoc - unlike the hundreds of watts of INTENTIONAL radiation from the aircraft's communication systems...
Isn't American Airlines rolling out WiFi in some of there planes? I can't turn on my Gameboy but the operator can run their own wireless network? On the other hand is the price for me bring righteous is I have to pay with my life I'll just turn my shit off.
It's only supposition, but my logic works like this:
- I would estimate I've taken about hundred or so flights in the time I've had a phone.
- I've left my phone on two or three times.
- I reckon I'm fairly paranoid and careful about turning my phone off in flight. Certainly compared to the mrs, for example.
- Say 100-300 people on each plane.
So I reckon that even if I am even more absent minded than I think I am, each plane probably typically flies with 3 or more phones turned on.
Even if I'm an order of magnitude out in my estimations, with tens of thousands of flights worldwide, there's thousands of planes flying with switched-on cellphones every day. If there was anything but the tiniest risk, there would have been hundreds of crashes by now.
(Which doesn't mean that I don't still think this is worth considering as important; when the consequences can be so great, even small risks are worth mitigating)
I have no problems.
...except with the FCC, which limits amateur radio transmissions to a maximum of 1500 watts.
Why can't people just turn off their electronics?
People act like they have some kind of God-given right to use electronics on an airplane. They back this up with "it won't hurt anybody" and "it's mine, I can do what I want" or "if it isn't broadcasting signals than it isn't a problem".
Guess what, all electronics generate some degree of interference. Commercial electronics are (sometimes) well shielded, but portable electronics aren't due to the small size, and even the best shielding doesn't 100% eliminate interference.
Because we are talking about a plane crashing or not, I don't think there's room for argument. By riding a plane you agree to abide by their rules, and if their rules are to turn off the electronics, you do it.
If you don't like it, find an airline that has a different policy. But don't act like the Constitution guarantees your right to tweet or text or play video games on an airplane.
And that's all I have to say about that.
OK, let’s try a simple example. A passenger has a cheap FM broadcast receiver. This receiver’s intermediate frequency is 10.7 MHz. The receiver utilizes “high side” injection so its local oscillator frequency is 10.7 MHz higher than the operating frequency. The FM broadcast band is from 88 to 108 MHz, this puts the LO in the 98.7 to 118.7 MHz range. The aircraft navigation band is from 108 to 118 MHz with ILS signals at the bottom of the band and VOR signals all over the band. The broadcast receiver radiates a portion of its local oscillator energy, this is very hard to avoid. The LO appears to the navigation receiver as an interfering carrier. The broadcast receiver is very close to the navigation receiver, the navigation beacon is many miles away, the inverse square law of radio propagation is not your friend, the shielding will not help you, there is an antenna on the navigation receiver, and the LO signal will escape to get into the navigation receiver. This example is very simple, and uses dirt common equipment. There are an untold number of consumer devices that could radiate unintentional, unexpected, signals in navigation and communication bands. When I’m flying, I can see all my passengers, and I can insist that they do as I say or get the hell out of my airplane , a commercial pilot can’t keep track of a whole bus load of people.
So what's so special about the signal coming from a cell phone until it gets outside the plane as compared to the signal coming from the cell tower to your phone (also inside the plane)? That doesn't change if your cell phone is on or off.
Lets generously assume that 1/10 flights has PED's on and that FTA there are 32000 flights per day and 75 actual PED incidents on 1/4 of the flights between 2003 and 2009. The probability that given an electronic device is on there will be an incident P(PED incident | PED on), is the probability that an incident happened and a PED was on divided by the probability a PED was on P(PED on ^ PED incident)/P(PED on)
(75 incidents/(32000flights*365days*7years*.25 of airlines surveyed))/(1/10 flights with PED on) = 0.003669% chance there will be an incident given that a PED is on
This is a gross understatement of the number of flights with PED's on my experience, in my opinion the claim that PED's will cause in interference is not borne out by the evidence presented.
"IPHONE LIKELY TO CRASH PLANES. Apple declines to comment. Google says Android is safe because it is open. "There is no plane-crashing code in Android, anyone can see for themselves." Nokia promises additional aircraft safety for its WP7 phones once they are bricked over the air this fall."
It's downright fortuitous that they have had a 100% compliance rate of passengers turning off electronic devices prior to this evidence, or the burning carcasses of planes would no doubt be littering the US from ocean to ocean. I'm sure all the major airlines will cut their maintenance budgets to fund further studies of this dangerous phenomena, the consequences of which, I think we can all agree, we have been avoiding by sheer luck, what with the thousands of flights a day and zero accidents attributable to it.
the article says "Boeing engineers told us that signals from PEDs could disrupt the navigation and communication frequencies on older planes, which are not as well shielded as the newer models." As the older hardware is retired the need for these rules will progressively diminish ... in the meantime please turn off all that electronic crap ... i mean really twitter ? facebook ? Is it worth your a$$ if you do happen to be flying on susceptible equipment ? More to the point is it worth someone else's ?
"including those for an instrument landing system used in bad weather."
ILS can't be used in bad weather. They will either switch you to VFR or make you change airports.
Thats what you need to keep avionics from being disrupted and vice versa according to the DoD, they've done a lot of testing on that stuff over the last 30 years.
You are comparing a weapon of war which *will* be aggressively attacked to a civilian plane which maybe, possibly, *might* experience brief interference from my cell phone? Talk about apples to oranges.
If interruptions from cell phones and other electronics were ACTUALLY a serious problem, they would either prohibit them from being transported, collect them prior to boarding or would take other measures to ensure they could not be used in a manner that could jeopardize the safety of the aircraft. Cell phones and similar items are not believed to be a meaningful threat to the safety of the aircraft or its passengers by the airlines or the FAA. The actions of the airlines and the FAA speak far louder than their words. Real threats would be acted upon. Simply asking us to turn off our phones and computers (they don't even check) means they don't really take the possibility of interference seriously.
Here we go again, every couple of years an article relating to avionics interference shows up in slashdot and I have to come out of my cave to save the world...
Here is something I wrote back in 2006 about this same issue.
Just because you are 'an engineer' who 'works with RF' doesn't mean you know tiddly about avionics. I actually work at an avionics lab and repair and test these devices and have actually measured RF interference of avionics systems, both on the ground and in the air. Its my job.
As a fellow engineer I could give you a 5 minute brief on how the ILS system works, another 15 to go through explaining all the board level receiver circuits, data busses and another 20 to go throught the navigation computer and autopilot at block diagram level - and afterwards you'd be rolling on the floor laughing to the very idea of a passenger ipod being able to interfere with 'the ILS system'... unfortunately my superiors are hunting me down to lock me back to my cave now.
For others see what I wrote about Ultracrepidarianism
www.tribalnetworks.org - helping tribal people around the world to own their own means of high-tech communications
Because .. testing every possible consumer electronics device which might end up on an aircraft, against all the possible aircraft, and all of the possible variations of an aircraft is damned near impossible.
Don't need to. If you are actually worried about this being a problem, you simply either prohibit the device from being brought on board or you *require* it to be put it in a Faraday cage to prevent any transmissions from being problematic. Hundreds of thousands of pieces of consumer electronics fly every day and you can be sure many of them are not shut off no matter how much the flight attendants ask. The general public essentially acts as a flying test bed and there has NEVER ONCE been an accident caused by any cell phone or other piece of consumer electronics on any airline. Everyday use has proven this to be a non-issue.
While the risk may very well be greater than zero, the actual risk has to be extremely low. If it were a real problem, the airlines and the FAA would demand we not fly with our electronics. Actions speak louder than words.
Eh? Exacly where are these mythical Cell Phone towers between Shannon & JFK? Or Perth & S. Africa, or any other route that flies over the oceans of the world.
They don't exist exept in your mind...
See also my follow up reply with a link to an actual published academic study on avionics interference. Have fun.
www.tribalnetworks.org - helping tribal people around the world to own their own means of high-tech communications
... then why do the terrorists spend so much effort trying to smuggle bottles of shampoo and other toiletries past the TSA perverts?
This is the first step to forcefully confiscating all travelers' cell phones and laptops, in an effort to make sure our airlines are secure.
Step 1: produce shoddy article, with circumstantial evidence.
Step 2: blame random plane issue X on PED Y.
Step 3: ban PED's on commercial flights.
Step 4: create ridiculous scanning device for "safety"
Step 5: PROFIT
Woah, almost lost my tinfoil hat in that rage!
Something witty.
I actually used to work on the ILS system back in my AF days. As i recall, the system was working in the 900 and 1800 bands, at least in the US. It uses a 90 and 150 Hz tone modulated onto the carrier. Naturally, it is simple modulation.
As it also happens nearly every single GSM mobile phone is quad band, which just happens to also operate in 900 and 1800. So, when you are flying around and have no signal, your phone is searching all bands.
And even though the freq is in a different part of the band, your phone is also making spurious emissions and harmonics, which can in some cases be only 10dB less than the carrier. That is enough to jam and ILS.
I'm hijacking this plane. If you don't give in to my demands, I will turn on this iPad!
It's all about money, it's expensive to get a device certified for operation during takeoff and landing. I've worked for a couple avionics companies myself, and getting the radiated/conducted emissions down to the approved levels is not always an easy task.
That being said, Amazon should pony up the dough to get the Kindle approved for use during takeoff and landing with the wireless off. I doubt there's much of a difference between the radiated emissions in its standby mode with the screen blank and when reading since it takes no power to maintain the text. They would have to test a bunch of page turns to get worse case radiated emissions and would maybe change some clock frequencies to avoid harmonics that can interfere with communication to air traffic control etc, but I doubt there would be any major hardware changes.
Open field EM testing and modifying the hardware to fix any deficiencies is not a cheap process, and it often takes many hardware revisions even when the design engineers are experienced dealing with the emission requirements.
Of course, your cell phone, laptop, whatever aren't interfering with aircraft avionics or comm systems. Or we'd be seeing numerous instances of aircraft dropping out of the sky.
What you don't see is the occasional 'squak' that a GSM phone can generate or the 'tick, tick' noise that WiFi equipment produces on a receiver in the cockpit.
In most cases, the occasional burst of interference is no more than an annoyance to the flight crew. Maybe they'll have to request a transmission be repeated. That's nothing you'd notice, so there's no problem. Right. One of the deadliest aircraft disasters occurred at Tenerife in part due to garbled radio traffic between ATC and a flight crew.
So please, turn your fucking iPhone off. If you can't be without it's continuous companionship, then don't fly. And seek help.
Have gnu, will travel.
the hidden cameras get all fuzzy...
I saw the episode where the Mythbusters busted this myth by sending out all sorts of signals inside a plane (that was unfortunately sitting on the tarmac). They also emitted WAY more than normal amounts of interference and there was still no disruption of electronics in the cabin. Mythbusters FTW!
I've worked as a telecommunications engineer for a long time, and for a long time I thought that this, whilst a possibility, was just as likely to cause issues as any freak of nature.
That was until I was on a bus one day, and every time my phone rang, the rear door of the bus would open. This was a long distance coach going down the highway at 110km/h, so the door opening wasn't a convenient coincidence. After the 5th time, I turned off my phone.
Whilst plane doors are manually closed, my belief that this could impact even the plane's coffee machine is enough for me when a few kilometres up. Now every time I get on a flight, my phone is off a long time before.
Internal sources of radiation are many orders of magnitude more disruptive for their power level.
That is not the same thing as saying they actually disrupt the electronics of the aircraft itself. Even granting that the radiation is amplified, the logic of your statement is a deductive fallacy. Saying "avionics are susceptible to interference from radiation" and then saying "aircraft bodies amplify radiation from consumer electronics" does not get you to "avionics are disrupted from consumer electronics". A + B does not equal C.
Somewhere there is an engineer that argued quite vehemently that there is no way the air speed sensors on an Airbus A330 could possibly all fail while the plane is on autopilot, leading the engines to stall in mid-flight. And even if it did, there are so many other redundant systems and skilled pilots to prevent the plane from crashing. Of course, that was before French investigators found the black box from Air France 447.
you have just come up with an argument for the banning all transmitters on the aircraft, including the VHF and HF air to ground, satcom etc, or even off the aircraft, under every flight path.
After all, the 'likelyhood of failure will never be zero' as you cannot guarantee a 'design flaw manufacturing / maintenance flaw'.
That is right isn't it?
Should we:
a. Ignore the problem completely, letting anyone use electronics on board.
b. Tell people not do, trusting that they won't, with perhaps minimal checks by stewards etc that will only stop casual users.
c. FIX THE GODDAMN SECURITY PROBLEM. Shield the plane, or whatever you have to do to prevent terrorists/stupid consumers who left the devices on in their suitcase from killing a plane.
The current idea of having flight attendents walk around and tell people to turn them off is MORONIC. If it is a real problem, then a terrorist could easily design a device to maximize disruption, create an auto-on feature that turns itself on when air pressure indicates it is high up and then give those devices away to people as games. The moron that decided we should keep using method B should be investigated for ties to Al Queada and other terrorist organizations.
I recognize security problems exist. I don't object to real attempts to fix them. I do object to fake PRETEND attempts that do nothing at all to fix a problem, but instead make air travel even more miserable than it already is.
I do not want to have to trust my life to a flight attendant catching people using these devices incorrectly. If you want me to do that, then you have to pay me to fly, not the other way around.
Note, I don't actually believe the study is relevant. I think they found some odd occurences and blamed them on the personal devices.
excitingthingstodo.blogspot.com
Is there anyone here who hasn't heard the pip-pip-pippip-pip-pippip interference pattern coming from speakers while someone's mobile phone is chatting to the base station? Usually happens while the pre-call setup is being done or when a text message is being received (or pretty much all the time if you have certain smartphones). I've also noticed this effect on live TV broadcasts - not caused locally but encoded into the actual broadcast itself and verified by rewinding my STB and listening again. Maybe it was just some carelessness on the part of a presenter with his phone in his pocket, but you get the idea - even the people who should be able to deal with kind of thing don't always get it right.
Now put that same mobile phone inside a faraday cage with a crapload of even more sensitive equipment you're trusting your life to. With nowhere for the omnidirection signal to escape to, it'll echo around inside that tin can until it is absorbed or dissipates (or whatever) and will therefore have a much larger potential to cause magnetic induction in things that it really frickin' shouldn't. If you aren't a total moron, you SWITCH IT OFF ALREADY! I'd rather not test the theory while my life (and 200-odd people's) depend on it, if it's all the same to you.
Thank you bananaendian.
I remembered reading your reply back in 2006. Thank you for posting it again.
I think the younger generation is very talented. They just need to slow down a bit and absorb history a little and remember that events that are happening today are from years of events from the past.
jee /. you are acting like high school students that don't understand why they should hush. Every student thinks that a little quiet talk is not going to cause a problem, but if you are a lecturer you would understand that this coming out from 30+ students can cause a lot of noise!
The regulation is for everyone on the plane, not just for you.
http://hw.libsyn.com/p/5/6/f/56f9995f59819e9c/skeptoid-4014.mp3?sid=9d5d540f74f62248fe57a99212f1d97e&l_sid=17974&l_eid=&l_mid=1406354
Just use some CRC validation goddamnit.
Somewhere there is an engineer that argued quite vehemently that there is no way the air speed sensors on an Airbus A330 could possibly all fail
There is/was no engineer that argued this. Instead the argument was, "if this happens, what can we do to improve safety in that event?" That failure mode was thought of, I have absolutely no doubt. Engineers thought it was covered, they may have been wrong about that but I'll discuss that later.
leading the engines to stall in mid-flight
An aircraft stalling does not involve the engines, it involves airflow over the wings. Do you have any knowledge of the topic at all? Nothing I've read indicates there was an engine failure on that flight.
The aircraft crashed because when readings became invalid, the computer automatically disconnected the autopilot / autothrottle (as it should have). The pilots then made control inputs that were inappropriate for the situation. They were probably confused by the relative lack of data they had, and the multitude of warnings a complete air data failure causes. The pilots then held a nose up attitude through multiple stall warnings, eventually entering a period of extremely high sink rate. The aircraft had pitched up in excess of 35 degrees through this period, and the pilots held full nose up control inputs through almost all of it. It was the exact opposite of what they should have been doing. The pilots held the stall all the way into the ocean, impacting the water while still in a nose up attitude of more than 16 degrees.
I know people like to get up in arms whenever a crash is blamed on pilot error, but it's pretty clear in this case that the pilot's actions were inappropriate and their inability to recover from the stall despite ample opportunity will almost certainly be listed as the main cause of the accident. There were many contributing factors, but the data suggests that the aircraft would have flown just fine if given proper stall recovery inputs.
What could the engineers have done better? Indicate in a more useful way what was going on and which instruments were reliable. The pilots should have been able to tell at a glance what they should pay attention to and what they should ignore. The avionics display design may not have been good enough for them to do that. The stall warning may have deactivated inappropriately based on the invalid speed, because the computer thought the aircraft was traveling too slow for the angle of attack indicators to function correctly. This failure mode should not exist in my opinion. Either the angle of attack indicator should function at lower speeds, or an alternate stall indication should be used instead. Or just keep the warning on, since the aircraft is quite obviously not in landing configuration. From what I read, they were probably assaulted with a whole host of failure warnings that were confusing and may have contributed to a panic reaction.
Also, pilot training needs to be improved in some areas, especially involving loss of pitot static data. There is no reason an airplane of any type should crash because of a clogged pitot tube. This should be drilled into pilots starting with the most basic beginning flight training. I know from experience the topic is not covered at that level, besides a couple questions that may appear on the knowledge test. In fact, if I had not actually had a pitot tube get clogged during my training, I would have never encountered the situation at all.
There's some fairly good discussion about the events of the flight here.
While I am sure you know very well how the ILS works at the level you described above, none of it really seems to have anything to do with signal interference.
How does the modem of the ILS receiver work? The ILS transmits on a 108-112MHz carrier frequency modulated at 90Hz and 150Hz. It would be easy enough to design a RF section and modem to receive whatever information being transmitted if it weren't for everything else that flying around in the VHF (aircraft communications and other things and UHF (personal electronics and other things) bands and the fact that your receiver is moving.
What happens when some guy's brand new, shiny LTE/3G phone (who he forgot to put into airplane mode or turn off) decides to transmit at a high power setting on an uplink signal because the base station gave the cell receiver a low gain channel estimation? The ILS receiver *might* see a pretty messy frequency spectrum. The ILS receiver may be designed to pick up signals at -100db, but it doesn't help much if you have your signal is at -50dB and being swamped by -50dB of noise by a relatively high power transmitter 10 feet away.
I agree that a single Ipod wouldn't cause much interference, but what about a quarter plane full of personal electronics with crystal oscilators running at all different frequencies?
A lot of people make the assumption that just because you have something called a GPS receiver, or cell phone receiver, ILS receiver, etc.; that you will somehow magically only receive those signals. Those receivers are specially designed for a frequency band where the signals are, but they will see everything that is broadcasting/leaking/oscillating into the frequency band . Also, transmitted signals don't just appear at a single place in the frequency spectrum! And finally, filters and signal processing techniques can only do so much... Eventually your signal of interest will get swamped with enough interference.
Like we haven't figured out that they want to condition the regulators and lawmakers to believe this bunk. The ultimate goal of this is so that the airlines can go back to selling us ridiculously expensive phone calls and other services....
Huh?
I've worked in avionics design, implementation, production, certification, installation and testing, and I've personally had to deal with interference issues both proactively and reactively.
The 5 GHz ISM band used by 802.11a/n is very close to the frequencies used by the MLS (Microwave Landing System: http://en.wikipedia.org/wiki/Microwave_landing_system). The risk of interference is both significant and real.
Despite this, equipment that is well-designed and properly installed should have no problems. Modern antenna systems have excellent rejection capabilities, so local interference typically enters the system via cables and connectors. Thus, the most important design/installation consideration is to have the downconverter be in the same enclosure as the antenna, so the RF signal travels a minimal distance in its 5 GHz form.
Unfortunately, even equipment that is properly designed, produced, installed and maintained can develop interference. It is best to assume vulnerability, since it is impossible to prove its absence, and the cost of failure is just too high to mess with. Other independent measures must be taken to minimize the risk of interference.
It not all that difficult to put the passengers inside a Faraday cage (http://en.wikipedia.org/wiki/Faraday_cage) by layering a very thin metallic mesh into the cabin wall and ceiling panels. This isn't as hard as it may seem, though 5 GHz is a slippery frequency to contain over a large volume. Unfortunately, cabin panels are rarely replaced, and it would take a decade or longer to get an entire fleet converted.
The largest problem comes from personal systems advertising in Ad Hoc mode (http://en.wikipedia.org/wiki/Wireless_ad_hoc_network). Many transmitters blast away at full power during the this phase. Also, as an aircraft descends and is on final approach it will fly through many WiFi networks (more every day), and many personal systems will immediately go to full power and try to connect to them, generating blasts of power when you least want them.
One solution is to simply provide a low-power network within the cabin. The network need not be a full internet connection (though that would be nice): It must only get all the other local transmitters to shut up! For a hardware cost of around $500 per aircraft (with much more needed for cabling, installation, and certification), a simple device can provide dummy signals for all protocols on on all cell phone and ISM bands. Yes, jammers should be able to do the job. The key here is to restrict the jammer transmission to the lowest rate and power needed to minimize transmission power and rate from local personal devices. The jammer timing can then be used to further limit MLS error.
The underlying issue is that aircraft systems evolve very slowly, with years of testing and certification needed to get novel RF technology approved for permanent installation in aircraft. A short term solution would be to provide the cabin crew with hand-held sniffers, and, prior to final approach, confiscate personal devices that are emitting any signal in any relevant band, and place all such devices into a small Faraday cage enclosure (many of the bins in the galley qualify).
Alternatively, passengers can be given heavily aluminized Mylar envelopes (personal Faraday cages) for their electronics. I think every responsible passenger should have one, and be required to use it during final approach, just to be sure. I do!
Who needs explosives? Bring your iPad on and leave it on...
http://www.penny-arcade.com/comic/2006/10/30/
Great post, very insightful.
From an electronic technician who's interested in avionics, is there a book you would recommend to get more specific knowledge on the subject?
so next time instead of a box cutter all they need is overclocking a cellphone? Will that disrupt the plane so much that the pilot lose control of the control surface, altimeter, landing gear, etc. If not the pilot should still be able to fly or land it.
Isn't there an airline over in Europe somewhere that has been allowing cell use on flights, and has onboard Wi-Fi for the last several years? If this is the horror that they're talking about, why aren't we hearing about those planes crashing every day?
Just saying...
This is what I don't understand. With all the discussions over this, how has this not been fully tested and answered? How can we not have a definitive answer by now? And if it has been answered, why it is still being debated?
Personal devices are evolving rapidly. There is no finishing point for testing, no definitive answer. In the article you will find that Boeing has identified devices that exceed acceptable emissions levels, the worst offender was an iPad. Tests from several years ago are obsolete.
Well, isn't it high time we invented it?
Funding agencies need to start funding high risk projects like these. Enough of directed research and optimization. Time to do some real science.
There isn't one confirmed instance of radio interference from electronic devices within an aircraft causing that aircraft to crash nor are there any fatalities ever reported from same. There are at least dozens of electronic devices left powered on on every domestic flight during takeoff and landing, no reports of "near disaster because of pax electronics." Worry about pilot error, flying into IMC without the right training & equipment, mechanical failure, sabotage, bird strikes, pilot error due to weather and human error (i.g. ATC). Those factors are responsible for 100% of fatal air accidents over the last 60 years. In fact, more people have died on airplanes from eating contaminated shrimp than using an electronic device.
And the financial experts didn't see the 2008 financial crisis coming... So I'll continue turning off my phone on take-off and landing because I like to increase my chances of living, even it if might be by only 0.00000000001%.
Yes, I'll be sure to check out your piece on Ultracrepidarianism.
That bulky cable going into the thing on his lap is waterproof, oil-proof, vibration-resistant and possibly Kevlar-jacketed. No doubt there's some shield but not very much more than COTS cables. Military Ethernet switches (e.g., http://sixnet.com/product/8-port-ip67-gigabit-managed-or-unmanaged-switch-174.cfm) are filled with resin to protect them from the harsh environment but not don't have any extra shielding.
it's not "Personal Electronics" that are interfering, it is signals from personal electronics. If everyone learned about going into airplane mode there is pretty much a zero chance of interference.
so this means cell phones cause boners?
911 911 911 - someone had to say it
The new right fascists are bilingual. They speak English and Bullshit.
I've seen several flights offering on-board wifi internet access and I even used it on a Flight from Dallas to Phoenix a couple of months ago.
So now wifi is safe but everything else isn't?
c'mon!
It's probably more likely to get avionics disrupted by cosmic rays than by a cell phone.
I can say this. Small airplane equipment can definitely be interfered with by devices like cell phones (and I'm not even referring to smart phones).
Speaking from personal experience, my cell phone interferes with the VOR on some small airplanes I fly, causing it to never lock on to the VOR frequency for the airport I am trying to land at while my cell phone is on. Not only have I verified this, but my mom (a professional pilot for over 30 years) has verified it, too. For those who don't know, the VOR is one type of navigation equipment used to line up with the runway, specifically in bad weather when an instrument approach is necessary. I have experienced this multiple times, always corrected by turning off the phone.
I admit, larger airplanes may or may not have more effective shielding (and definitely could), but do you really want to risk such a problem just because you are too lazy to turn off your electronic devices?
If my cell phone can bring down a comercial airliner, I think it's time to replace the airliner.
How can anyone evaluate this when the Article Is Not Available. (Page 404)?
Isn't it kinda stupid to post stories from sites that don't keep anything up for more than a couple days?
Jeruvy