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The Real Reasons Phones Are Kept Off Planes
jcatcw writes "Mike Elgan argues that the the real reason that cell phones calls are not allowed is fear of crowd control problems if calls are allowed during flight. Also, the airlines like keeping passengers ignorant about ground conditions. The two public reasons, interference with other systems, could easily be tested, but neither the FAA nor the FCC manage to do such testing."
There are already enough planes that have satellite television (including news channels) along with air phones (at a very high cost - yes but still a source of information.
The real reason? Its bad enough when people are yapping on their phones constantly on the ground. Getting stuck on a plane near someone who won't shut up on the phone is MUCH MUCH worse due to the duration and the captive audience. For that reason I hope cell phones are never allowed (and if they are it should be a cell phone only section kept reasonable sound proof from the rest of the plane).
With no players anymore in the US, Verizon out and aircell now offering Wifi instead of phone calls, this is not a reason.
Also the only phones still avaliable on planes are run by ARINC and SITA, which both now have a picocell replacements under testing for installation this year.
There is no technical nor marketing reason you can't have a cell phone on board, if cell phones were a real danger then they would not be in carry on allowance anymore.
FAA is very conservative, and the FCC is a political body.
That is all
-- email me @ 30,000 ft
I posted this to the original article as well, but I felt the slashdot community might derive some value from it as well. The interference issue is a VERY real one. I can't emphasize this enough. It's easy to debate this issue on the ground, but try debating it 2 miles above the ground when your only lifeline is a thin needle on a panel that is controlled by a radio transmitter on the ground. I have a personal experience with cellphone nav interaction. I've also watched the mythbusters episode. Everyone here knows that mythbusters, while entertaining, is not entirely scientific. I certainly am not willing to stake my life on the thoroughness of their conclusions.
Without further prefacing, here is my original post:
You mention in your article that "Many headsets used by private pilots come with jacks for using them with cell phones. The manufacturers say they're for use on the ground only. But many private pilots use them in the air without incident."
I fall into this category. However, I've also seen the dangers of airborne cell phone use. I carry a Nextel branded Blackberry. From my experience, it's not a very good phone to use on board an aircraft. About every 20 minutes or so, the phone goes into a signal frenzy. It's as if it finds multiple strong towers to connect to and is unable to choose. This results in a barrage of beeps and lights while it tries to figure out what's going on.
Furthermore, the risks of interference are very real. When I'm using the phone, I never notice the interference. I recently let someone else use my phone and was very surprised. My headset (flight radio headset) emitted a horrible scratching noise. I was totally unable to hear anything on the radio. I quickly looked at my VOR (radio navigation, NOT a gps) , and noticed that it was off coarse as well. Now, had I not been certain that I was on the right course, I might have well thought I was off course and corrected in an ultimately wrong direction.
I'm not sure if you're familiar with VOR technology, but it's the primary aviation navigational aid. GPS is wonderful, but it's still not the primary navigation mechanism. GPS is considered a "non-precision" navigation tool. VOR and ILS are still the primary mechanisms and they are dependent upon terrestrial radio transmissions. This is where the cellphone interference comes into play. Most cell phones operate in the 800mhz range. I'll save you a lesson in radio technology by simply stating that they can often have harmonic emissions in the same bands as used for aircraft navigation.
While you state that countless numbers of phones are left on during flights, this is not particularly dangerous. A phone ranging a tower is only actively transmitting for a very short period of time every 20 minutes or so at regular speeds. A phone that is in active use is a source of radio emissions that is in VERY close proximity to the aircraft communications and navigation antennas and is operating on a frequency that can have interfering harmonics. I have personal experience with the reactions a nav needle can have to a cellphone.
Imagine if the weather was bad (instrument meteorological conditions or IMC) and you were trying to land a large passenger airliner using nothing but a small needle on the panel to align with the runway. Then, a passenger starts talking to their uncle Bill about his bypass surgery and that needle jumps even 10 degrees off position. Now, instead of aligning with a runway, you're aligning with a corn field.
To answer your thoughts about shielding, that's not a viable solution. You would either have to shield the passenger cabin from radio emissions or shield the comm/nav antennas from it. In either case, the shielding to protect them from each other would seriously impair their usefulness. A passenger cabin shielded from RF emissions wouldn't allow your cell signal to get out, thereby negating the purpose. Shielding the comm/nav antennas sounds like a good idea until you realize that oftentimes nav aids and aircraft controllers a
TFA says:
Real testing has been done. Unintended emissions from the phone have been identified as the culprit, not a deficiency in the navigation equipment. The aircraft's receivers are doing exactly what they are supposed to, responding to signals of certain frequencies arriving at the antenna. Once the phone pollutes the spectrum with spurious signals, nothing can protect the receiver. The shielding and filtering must be applied at the problem, which is the phone. Since the competitive consumer phone market demands the lowest possible cost, once a phone meets the minimum legal requirements they won't add another dime of product cost for further interference control.
Intereference does not occur every time, but when it does occur there has been a demonstrable cause and effect relationship. Start with this NASA case study(long pdf warning).
Then consider this article from Spectrum. On page 3:
And from page 4:
It's no conspiracy, and no urban lege
Yep. The coverage of even a small, low-powered VHF radio increases dramatically when operated from an aircraft.
In the U.S., Class A FM broadcasting stations are limited to a power of 6,000 watts at a maximum antenna height of 100m. Higher antennas are allowed if the power is reduced to compensate. At an antenna elevation of 600m, power must be reduced to only 150 watts (?!) to achieve the same distance coverage. Translate those figures to a cell phone with a rated power of no more than 3 watts, and you're talking about limiting power to 0.08 watt at 600m.
Of course, commercial aircraft fly a LOT higher than 600m!
The cellular network has far more subscribers than it has channels. To work, it depends on the ability to reuse a channel throughout the service area. If I place a phone call from my home 40km northwest of Nashville, the same channel can be reused in downtown Nashville, and on the city's west side, and in Donelson, and Brentwood, and Smyrna, etc., etc... My phone, about 1.2m off the ground, has a range of only about 6km.
If I place that call from an airplane flying 8,000m above my home, every base station in the greater Nashville area can receive my signals. Now, "my" channel cannot be reused at all.
If it were just me, that wouldn't be a problem. If it were, say, 10% of the passengers on each flight - well, I don't think it's hard to see how that could use up all available channels in a hurry. New channels aren't cheap. Nextel is paying to replace almost *all* the microwave remote broadcast equipment in use by U.S. TV stations, so they can free up some remote broadcast spectrum for use as cellular-telephone channels.
Here's an idea: allow calls from aircraft, but allow cellular providers to charge enough extra for airborne calls to cover their costs in adding more channels. I'll bet after the next billing cycle, the number of calls made from aircraft would plummet!
If cell phones and two-way pagers indeed had the ability to interfere with aircraft to a point where it compromises safety then the TSA should be confiscating them rather than bottled water and toothpaste. At least it's a more plausible threat than "liquid explosives". Perhaps the fact they are *not* confiscating them is telling.
Actually I'd like to see that. Confiscating a bunch of inexpensive water bottles in the name of security is a relatively benign way of maintaining the appearance of security. Being willing to risk massive public fallout by confiscating expensive cell phones would show they are actually serious.
I can verify from personal experience that MY cell phone does cause interference with radios. I'm a Private Pilot and I have a two year old Sony Ericsson. If I forget to turn the phone off, I can hear a cycling beep sound in my headset every time the phone is transmitting (i.e. ranging to a new cell tower or checking my email etc.) The VHF set also shows that it's receiving, so its actually picking something up through the antenna.
It's not particularly loud, and I haven't had any trouble hearing ATC over it. On a commercial jet... with several hundred cell phones, and the much higher importance of ATC calls under IFR... I can see where it could be a major problem.
Are there ways to solve the problem? Sure. Is it really worth spending the resources to test and resolve in light of the social factors? I'd say no. I personally consider time spent on commercial flights as downtime. I don't want people to be able to get ahold of me, I want to read a book or watch a good movie.
If you really are important enough you HAVE to be in communication 24/7... well buy your own jet =)
"42"
Cell phones do interfere with other devices - that the nature of all electronics - especially ones in which radio transmitters play a leading role. There is no getting around the fact that cell phones create radio 'noise'. Yes, they have been tested to make sure they are only creating radio emissions to some agreed upon level in the band/frequencies they are licensed to transmit on, and some (lower) agreed upon level outside of that band. However, certifying electronics for use on-board planes is a little more of a dicy issues - because the mere possibility that booting up your laptop during landing might generate enough noise to screw with the GPS, or the ILS systems that are helping the pilot guide the giant metal tube full of jet fuel and fragile humans to a concrate surface is a scary enough scenario that the FAA has decided its easier to just have a blanket ban on such things during take-off/landing. The ban on cell phones is a similar conservative (or paranoid if you prefer) move: its easier to say its not allowed than to test its enough to be reasonably certain its safe. In reality modern digital cell phones inside a modern jet could be perfectly safe - but there are a large number of models of airframes out there, and a much much larger number of cell phone models - many of which can operate in several different modes and corresponding frequencies. Certainly I'd prefer they spend the time to check it out some more so that in the future they can certify my cell phone is safe to use on the particular plane I'm stepping onto so I can talk during particularly long flights. In the meantime I have to wait until the plane taxis to a full stop by the gate before powering it up and making the call to say we've landed. An inconvenience, but I don't mind the fact that they're focusing more energy on the making the plane safe part and haven't devoting their full energy to making it easier to make phone calls during the flight part.