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Cell Phones and Air Safety
Cutie Pi writes "On the heels of this recent Slashdot story discussing Wi-Fi use on airplanes, the BBC is reporting about new evidence indicating that cell phones can interfere with airplanes' navigation systems. From the article: "In tests, compasses froze or overshot, navigation bearings were inaccurate and there was interference on radio channels." Look like like Wi-Fi and airplanes just don't mix."
Wifi uses far less power then cellphones do.
autopr0n is like, down and stuff.
yea they are supposed to be banned during lifeoff and landing because they can potentially disrupt transmission from ground control. They are usually allowed once the plane reaches a certain altitude.
Great Atrocit
Well, that nice aluminum skin makes for a good shield from outside interference. Inside, though, there's practically nothing in the way - all support members on modern planes are made from (thin) aluminum used sparingly, or carbon fiber / fiberglass. Most, if not all, of the deck support system on Boeing's newer 7x7 planes is made of carbon fiber, which doesn't do much to shield the avionics bay underneath from the cellular signals. Shielded cables also don't work well when they're 20 years old and have broken and been spliced in multiple places, degrading the shielding characteristics.
Every cloud has a silver lining (except for the mushroom shaped ones, which have a lining of Iridium & Strontium 90)
According to the register,
British Airway is set to introduce on-board broadband services next month. and Connexion By Boeing has received to go ahead from the US Federal Aviation Administration to use WiFi networks with satellite links aboard planes, after satisfying the authority that the technology is safe.
Anyway, your cell phone won't work on a plane, it goes to fast to do hand-offs between cells properly.
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because I think it's ridiculous that it could really be harmful. I guess I was wrong?
Do you leave it on in your pocket when you fill up with "gas" (petrol) too because it's ridiculous that a spark could cause an explosion of fumes ? Do you smoke while filling the car up too ?
Put your phone next to your car antenna and turn the radio on, and turn the phone on - hear that "dut-dut-der-dut-dut-der-dut" pulsing ?? Notice how you get the same effect when you drive to the airport (from their radar) ? Do you figure maybe a cell-phone that can't get a signal so has upped its power output to max to try and get one, about 20 feet away from the plane's antennas is going to providea stronger pulse than the radio signal being transmitted from 5 miles away ?
I was standing on the tarmac waiting to board a flight in Pakistan, next to a 747 that was being re-fuelled (which was freaking me out anyway - the av-gas fumes were really strong), and the people behind me decided this would be a good time to light up a cigarette... (they were german, said something about being ridiculous when I told them to put their lighters away and put their "f*ckin fags out").
I spent a lot of money on booze, birds and fast cars. The rest I just squandered. - George Best
The "dut-dut-der-dut-dut-der-dut" interference on amplifiers (and CRT screen distortion) caused by mobiles seems to only occur with GSM900 phones. I was used to it happening all the time when I lived in Australia (where use use GSM900) but I've never had it occur in the US with my GSM1900 or CDMA1900 phones.
Cell phones are banned from gate to gate. You are not allowed to use them during flight.
I recall an anecdote of a lady. She used her phone while approaching the airport (coverage in the air would be absolutely amazing) and was met at the gate by law enforcement.
They are *not* allowed in the air.
... that's all i wrote...
Both the airline industry and the Federal Communications Commission ban the use of cell phones aboard commercial flights. But they do it for different reasons, reasons which are contradictory and scientifically unsubstantiated, critics say. http://www.privateline.com/Cellbasics/cellphonesai rlines.html
[Fuck Beta]
o0t!
Do you leave it on in your pocket when you fill up with "gas" (petrol) too because it's ridiculous that a spark could cause an explosion of fumes ?
Ridiculous.
Do you smoke while filling the car up too ?
Not ridiculous.
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Improvements in shielding have no effect, of course on on-channel interference (antenna conducted), such as would be caused by poor out-of-band emission performance of consumer grade electronic devices.
With the advent of more composite construction in these new airframes, it is conceivable that they may have less airframe attentuation than the older models, allowing cabin generated EMI to couple via the antenna path.
A perfectly shielded communication or navigation receiver is still a radio receiver, which can be jammed by passenger electronic devices. Consumer electronics equipment is designed to be cheap, not to minimize spurious emanations. Radio transmitters commonly have spurious emanations. They may be suppressed by a reasonable amount, but that may not be enough if they are near a receiver that is receiving a weak signal. Then there is interference caused by intermodulation. All you need are several strong signals and a nonlinear junction.
Mea navis aericumbens anguillis abundat
Happens with my GSM1900 phone.
GCHQ Quantum Insert installed. If only our tongues were made of glass, how much more careful we would be when we speak
Here's a report (pdf) that discusses the interference effects of cell phones on aircraft: Interference Levels In Aircraft at Radio Frequencies used by Portable Telephones An html version is available on google.
Executive Summary
Measurements made on two types of civil transport aircraft confirm that transmissions made in the cabin from portable telephones can produce interference levels that exceed demonstrated susceptibility levels for aircraft equipment approved against earlier standards. Since aircraft equipment in this class is currently in use, and can be installed, and is known to be installed, in newly built aircraft, current policy restricting the use of portable telephones on aircraft must continue. Recommendations are made to reduce the interference risk and for further studies to understand more precisely the effects of interference to aircraft equipment arising from the use of portable telephones.
I doubt the terrorists were navigating on Instruments and cell phones dont usually affect VFR navigation.
Pete
Although these are widely accepted beliefs, there isn't a whole lot of evidence to support them.
It's clear that using cell phones can distract drivers, but it has yet to be shown to be worse than many other types of distractions.
They are usually allowed once the plane reaches a certain altitude.
Not on board any plane I have recently been on (quite a few, that is).
All electronic equipment (e.g. also laptops) is banned during take off and landing. Anything with an antenna is unconditionally banned during the entire flight.
Linux user since early January 1992.
Cell phones can work in planes. When you zip over the country, your cell phone antenna has an enormous range due to the fact that there are basically no obstructions compared to the walls and trees present on the ground. But the service providers really hate it, because you leave old and re-enter new cells at an extremely high rate, which generates a huge amound of traffic in the respective cell towers.
Switch back to Slashdot's D1 system.
In answer to your question: Civil Aircraft navigate using a variety of methods. Depending on where in the flight programme these are, this could be anything from VOR (Very High frequency Omni Directional Range) system to a Heading Select system ILS system or ADF. The Nav system itself functions using a variety of inputs including VOR (Military systems operate on TACAN (Tacital Area Navigation) which uses UHF rather than the mid band frequencies that VOR uses), Compasses, Accelerometers, Gimballs, Gyros as well as Ground Mapping RADAR fixes, GPS (these days), JTIDS (Joint Tactical Information Distribution System -Military again), On-Top fixes, HUD fixes and Offset fixes in addition to ADF (automatic direction finding) These inputs are used for comparison within the autopilot which uses a triplex (usually) voting system to decide what to show and what to do. (obv this various from system to system) So, finally, in response to your question, yes the plane does use a compass to navigate and whilst all these sub-systems are designed to promote redundancies within the larger system, they are taken into account and in the event of a larger systems failure, may be relied upon more than the pilot may realise - hence one of the major problems in over reliance on redundant systems...your perceived level of safety increases thereby causing you to change your actions accordingly and hence reducing the overall safety of the craft. - But thats another story. Incidentally, the reasons for not using cell phones on planes are neatly put at this link Airborne operation of PEDs [PDF] (I am not a pilot)
You get 50 times as much radiation from background sources like the sun, the earth (plants & minerals),etc. than from any man-made source like consumer electronics.
But don't take my word for it, read the CDC study.
I sure hope they are using more than a compass to navigate a commercial plane.
They do.
The compass is there to fall back on in case the sophisticated stuff quits working for whatever reason. And yes, a cellphone can interfere with the magnetic compass. I know, I'm a private pilot and own a small aircraft. Every bit of electrically operated gear in the cabin jacks with the compass's reading. Since I *know* how the electrical equipment that's installed and certificated as part of my aircraft affects my compass, I can deal with and compensate for that since I'm intimately familiar with all that gear.
It's all the *unknown* electrical devices that are brought on board an airliner and operated by passengers, that an airline pilot doesn't need to be made to worry about and wonder how to compensate for because if the situation has deteriorated to such a bad point that he's having to use the mag compass, you want nothing to interfere with it.
Now you might want to say,"How often does everything really go wrong and the pilot have to use the old fashioned mag compass to navigate?" Well, not very often at all in fact extremely rare, but I have to ask you, "How many times have you needed the spare tire in your car"? Well, I've driven my current vehicle over 150K miles in the past 11 years and never needed it, but that still doesn't mean I'm going to remove it or let the air out of it, or not check to see if it is in roadworthy before embarking upon a long trip, so why should the airline pilots risk the integrity of their last backup spare navigation instrument just because some selfish passengers want to play with their toys on board. Hell, the passengers should consider themselves lucky they are still allowed to fly at all and not having to make do with only ground and water transportation.
OK, so cellphones cause trouble...I've read stories in airplane magezines where cellphones affected small-plane avionics.
BUT...to say "planes and WiFi" don't mix is inappropriate, since:
(a) the article makes no montion of WiFi
(b) WiFi is lower power
(c) Wifi is in the 2400MHz range. CDMA is 1900GHz, GSM is 900/1800/1900MHz, depending on where you are.
CLearly, if Lufthansa felt that WiFi was no threat to avionics, they wouldn't be testing it on international flights OVER WATER.
Government's idea of a balanced budget: take money from the right pocket to balance...oh who am I kidding?
Remind me never ever to board a plane with any of you selfish fuckers who are so afraid of going without using their precious toys that they'd put the safety of their fellow passengers at risk.
The world's aeronautical authorities don't do this sort of thing for fucking fun you know. This is serious business, and some of the responses coming from know-nothing fuckwits on this forum fill me (as occasional plane passenger and as a pilot) with horror.
"Information wants to be paid"
I have a friend who used to work for Motorola and another friend who is a pilot and have disscussed this many times with both of them. The pilot friend has confirmed that in reality there are no issues with cell phones, or almost any other consumer wireless technologies aboard aircrafts. It does introduce some risk when flying under instrument flight only, but cause no problems during normal cruising. With this information I was left wondering why they are banned in most commercial planes. My friend from Motorola explained that when the cell phone system was designed it was not designed to hand off calls from one tower to another tower for a phone traveling at such great speeds. In fact if you drive too fast on the road (something over 140MPH in testing) you will also have problems. Planes are flying high causing you to access multiple cells at once and you are moving to fast for the handoff to occur from one tower to another. For this reason cell phones have been restricted on commercial planes. In fact amateur radios which put out far more power than a cell phone or wifi cards are allowed to be used on planes pending the pilots permission, this confirms that it's not an issue as it is not prohibited by FCC rules. It's not reallly an interference problem, it's a policy and cell technology problem.
No, they don't. The systems are completely different: cellphones are optimized for use on the ground, while the airphone systems are designed to be used from the air. The frequency allocations are also different.
The airphones also have exterior (to the airplane) antennas, and the systems were tested at the time of installation to confirm they do not interfere with the aircraft navigation or communication systems.
...but at a range of tens of m I don't think so.
One thing we are told about mobile 'phones is that they emit "2 watts" - we are not told that this comes as very steep pulses peaking at 200W. Domestic microwave ovens start at 600W and work up. What you are holding against your brain-case is a third of a microwave oven.
Nevertheless a highly inefficient 200W (mostly) electric transmitter in a metal tube full of absorbtive objects like water-filled (70%) human bodies is likely not going to generate a strong enough magnetic field to seriously upset a compass tens of m away behind a metal firewall. And at a range of 10m an omni 200W electric signal isn't going to be so curious about a small needle in an electrically shielded case.
Got time? Spend some of it coding or testing
I'm sure that sometimes cellphones are scapegoats for other problems, but remember that with the number of flights that happen every day, things that have infintessimal probablilities of causing problems will cause a few incidents a year. Even something that will cause a problem 0.001% of the time will cause at least a few problems per year.
Extremely rare combinations will happen fairly often in aircraft simply due to the number of flights. Maybe a gamboy and five Dell laptops and five cellphones left on will interact poorly and cause a problem in all of the VOR systems from a particular company made on the first of the month. This is still a problem, but hard to test for. If in some extrememly rare circumstances cellphones cause problems, it's easier just to ban cellphones.
Copyright Violation:"theft, piracy"::Anti-Trust Violation:"thermonuclear price terrorism"<-Overly dramatic language.