The protective effect of cell phones

| Comments (4) | Networking Outstanding!
I'm in Boston today for the IETF P2P Infrastructure workshop. Anyway, we land and as usual, as soon as we land they tell us that we're allowed to use our cell phones but other electronic devices have to stay off until they open the aircraft doors. So, wait a second. I can't use an iPod, but if it's an iPhone that's totally different and I can use it? Do cell phones emit some sort of protective radiation that I'm blissfully unaware of? Is it different between CDMA and GSM? If I have a laptop and it's got a cell modem in it, is that OK? Does it have to be built in or does a USB cell modem provide the magic safetyfying effect? Would it work if I just duct taped my cell phone to my laptop? Outstanding!


The secret to using your iPod while taxiing is to hold it up next to your ear so the flight crew *thinks* it's an iPhone.

Legal compliance, probably.

Your airline has to make the determination that a given class of portable electronic device does not interfere with the airplane's navigation or communication systems, or else the crew must prevent you from using the device. This is required by 14 CFR 91.21(b)(5), and I think it could involve rather expensive testing, paid for by each airline for each class of device on each model of airplane it flies, during every phase of flight.

In your case, it's possible that the airline did make the required determination for cellphones (or what the FAA calls T-PEDS: transmitting portable electronic devices) during taxiing, but found it economically infeasible to do the same for every class of device that it allows during cruise flight.

(Did you fly on a Boeing 737? Was it operated by Continental Airlines?)

I've always assumed this rule had nothing to do with electromagnetic interference and everything to do with keeping aisles and area around your feet clear while the plane is taxiing. In the event that an emergency evacuation is necessary, your mobile phone won't get in the way, but a laptop, portable dvd player, or even a walkman with headset cables strewn across your lap, will get in your way or your neighbor's way.

In the event that an emergency evacuation is
necessary my 800 page book will get in the way
more than my iPod or walkman. But my book is OK.

The whole idea that cellphones interfere with an
airplane's navigation and/or communication system
is a crock. If that were the case imagine how easy
it would be for terrorists to attack a plane. Just
buy tickets and leave your cellphone on in your
pocket! I have certainly forgotten to turn off my
cellphone when flying.

The only "bad" thing that happens when you leave
your cellphone on in an airplane is that when you
are taking off and landing it screws up the
infrastructure since your phone is seeing upteen
cells and handing off at hundreds of miles per
hour (which is not the norm).

The FAA can come up with any kind of cute acronym,
it doesn't matter. Airplanes insulate themselves
from such interference.

"For your safety and the safety of others". That
is the key phrase that is used to justify every
sort of inanity in our society. And how can you
argue with that?

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