First Cellphone Use On Airplane Given OK

s31523 writes "With over 1 billion cell phone users worldwide, and with so many business travelers, using the cell phone on the airplane has been a recent hot topic. Emirate airlines is announcing they will give the OK for cell phone use on their planes, making them the first airline to do so. The FCC and FAA still ban the use, but are working to determine safety implications, if any."

Issues are technical, not just regulatory

[bugnuts]

Let's ignore the issues of cellphones interfering with the flight controls. We'll ignore that search for a random cellphone on some oriental airline long ago, purported to be messing up the landing.

From what I understand, cellphones work by associating themselves with "cells" of coverage. The closer they are, the less power they use, and so on. When the user moves cells, the network switches them over to the new cell.

From the air, a cellphone will see many, many different cells as being equally good. It will also have to switch across cells much faster than normal. Without the plane itself acting as a roving cell tower for the occupants, it seems to me that this would cause a lot of problems. Not only will all the cellphones be transmitting at full power, but the network will potentially have to handle many many more switches cell to cell, and faster than normal. There's evidence of this from TFA when it said some upscale, long-haul airlines are installing equipment onboard that will allow for cell phone use.

I'd love to hear from anyone in the business that could shed more light on these technical issues, and whether they are as big of a problem as I suspect if airlines were to just say "Sure! Use your phone!"

Re:Good news for Bose

[devilspgd]

Actually, they don't do a fantastic job of blocking voices. In my experience it's actually easier to hear conversations using noise canceling headphones then without, since the headphones cancel out the other background noise.

Re:Issues are technical, not just regulatory

[TheRaven64]

With a cell site in the plane, your phone will go into low power mode and just talk to it, not any of the towers on the ground (in theory, at least). It may see other towers, but won't try to switch to them, because they will be weaker signals than the one a few metres away.

The cell in the plane will communicate with a base station somewhere, probably via LEO satellites, without interacting with the rest of the phone network. Once the call reaches the ground, it will be routed accordingly. Equipment for the second part (getting the calls to the ground) is already in many planes for the phones you will find built into seats. The only difference is that now you can pay a lot to use your own handset, instead of theirs.

Re:To those confused

[vtcodger]

Good post, but may be a moot point with current cellphone technology.

My frequently faulty memory tells me that somewhere -- probably here on slashdot -- in the last year or so there is a link to an article about a test of cell phones on aircraft in flight. At low altitude the cell phone worked fine. At higher altitudes -- above a few thousand feet -- connections were not so good.

Here's a link to an article (not the one I had in mind) about some 2003 tests in the vicinity of London, Ontario using several different cell phones and both metal an fabric skinned aircraft. Bottom line: Cell phones work pretty well at low altitudes, but the liklihood of a usable connection drops off rapidly with increasing altitude. At 8000 feet, the liklihood of connecting and conducting a conversation is below 10%. If their lower altitude results apply at higher altitudes, they project the liklihood of a connection at 20000 ft to be pretty close to zero. http://physics911.net/projectachilles.htm [physics911.net]. They also discuss the handover issue and seem to conclude that at 500mph, there isn't enough time in each cell to complete the handovers necessary for call continuity. At least that's what I think they are saying.

Re:The other issue ...

[eln]

You probably have a CDMA phone. GSM phones, such as those used by Cingular, cause interference with various noise-emitting devices. My desk phone at work always buzzes about a second before I get a phone call on my Cingular phone.

Re:Anybody Try to use one on a plane?

[Anonymous Coward]

Mythbusters had an episode on the cell phones with airplanes issue. Cell phones were not shown to have any effect on navigation controls, but a highly amplified signal did have an effect. Since cell phones on an airplane will probably need to operate at near their maximum signal power to stay in contact, this could be an issue if many people were using cellphones simultaneously--especially during takeoff and landing. Other than that, a couple of people using cellphones during cruising operations shouldn't be a problem--except that they might be murdered by other passengers if they talk like the typical teenage girl when everyone is trying to sleep (which would probably be justifiable homicide).

Re:Cellphones don't endanger planes.

[thpr]

Your prior post is interesting, detailed, and well-informed reading, but you fail to address an existing, published study [cmu.edu] stating that cellphone use on aircraft may be dangerous.

Not exactly news, but CNN thinks so

[eggboard]

Emirates said months ago that they were going to add this service, which uses an on-board picocell and relays calls very expensively very satellite. Should run at least US$2.50 per minute for calls. I wrote about this in The Economist back in September (not Emirates news): RyanAir will launch in-flight calling by the second half of 2007 on hundreds of its planes. That will be the first major deployment.

Re:Cellphones don't endanger planes.

[bananaendian]

Your prior post is interesting, detailed, and well-informed reading, but you fail to address an existing, published study [cmu.edu] stating that cellphone use on aircraft may be dangerous.

I'll address this again then.

The study says there is an 'increased risk', 'higher than was previously thought'. What they did, was find that more often than thought before people's cellphones were on during critical parts of flights. They also found that laptop wifi and bluetooth were emitting RF. All they actually did was log the spectrum from these emissions on some flights. That is all their research found.

Now, what they imply is that this is somehow more significantly dangerous then we previouly thought. My essay [slashdot.org] I think covered most of the things why this is not so dangerous.

However I want to stress here the fact that any potential emissions from consumer RF-devices in the cabin will have a hard time competing with all the structures and shielding between the device and the antenna outside the aircraft or inside in the avionics bay. And no such device can dream of competing the awesome power of the spectrum from a fairly common natural sources, such as static build-up and lightning, under which such avionics have to perform on a daily basis.

And if people are already leaving their cellphones and laptops on during flights by accident, where's the harm in allowing them to use them during flights in a controlled and tested environment. This might actually help people remember to turn them off more often during takeoffs and landings.

Re:Anybody Try to use one on a plane?

[Anonymous Coward]

The people on the planes during the 9/11 atacks used Airfone, not their cellphones. Airfone was installed in thousands of airplanes since it's introduction in 1984. It's costly to use but somehow I don't think people really cared about cost at that time.

How else did you think the Airfone operator got hold of the recordings we've all been able to hear? You think the mother of Mark Bingham had a recording device ready just in case her son's plane would be hijacked and afterwards gave the recordings to Airfone?

Re:wow...this is a hot topic

[mark-t]

It's always been technologically possible to make cell phone calls from the plane, it's just not actually ALLOWED.

Re:Cellphones don't endanger planes.

[Coffee.RF]

You need to go back and watch that episode again. I've worked in both avionics, and the wireless industry, so I recorded it and have watched it several times just for laughs. The situation you are referring to was TOTALLY bogus. Instruments out of the rack, no shielding for the wiring, etc... You can't get much further from a real aircraft installation. (btw, it was a GSM handset, and I think they were testing at 800MHz) Additionally, when they did try a real aircraft, there was absolutely no effect from the cell phone. Given the frequency domain differences, cable shielding, and spatial diversity in an aircraft makes the amount of energy from your cell phone the equivalent of 'a bug on the windshield'.

Re:Anybody Try to use one on a plane?

[Anonymous Coward]

It is a myth that it causes interference with the electronics. Their argument is that any electronic device emits a frequency that can disrupt communication (even a hard drive emits a frequency). That's why we cant use them on take off and landing. But that is mostly because they don't want someone to be plugged into their mp3 player while trying to give directions on how to survive a crash landing. I have had my cell phone on during a flight and it is quite hard to get a good signal 25-30,000 feet up. People have done success rate studies and at 3000 feet there was only a 5% success rate of a stable phone call. The remedy is putting a mobile cell phone tower in the planes themselves. I know america airlines is working on that. Regardless, the frequency of a cell phone and their radio equipment is incredibly far apart.

Re:To those confused

[MindStalker]

Actually if you havn't noticed most all hospitals now let you use your phone in most areas.

No sidetone?

[kalleguld]

All my phones have had sidetones (at least if I've gotten the term right). Have you ever tried blowing into the mic on your cell? Then you can easily hear the sidetone.