There's a lot of disinformation in this area, and not that many facts. However, Lufthansa has said that on average, one phone is left switched on on every flight it makes. I'd be surprised if that wasn't true for just about everyone. If there was a problem, it would have surfaced by now. And it would have been fixed -- you can have seat-mounted radiation detectors, crew-carried radiation detectors, small blocking transmitters in the cabin that prevent phones from working during flight, screening film on the windows... lots of options, none of them free but then since when is safety free?
In any case, you ain't seen nothing yet. As well as cellular radio services on four frequencies, there are 802.11, 802.11b, 802.11a, Zigbee (aka 802.15.4), Bluetooth, WirelessUSB, UWB (which is ALIEN TECHNOLOGY, I tell ya), cordless mice on 49, 433 and god knows what MHz... and that's off the top of my head. Some or all of the above is already part of those sleek silver gadgets called personal digital assitants, smartphones, pocket PCs, MP3 players or whatever, and more is on its way. I've seen an MP3 player that has a built in frequency-agile Band II broadcast FM transmitter (
www.neurosaudio.com) to let you listen through your hifi or car stereo without wires. Band II broadcast FM is right next door to VOR frequencies... but it's just an MP3 player, right?
Not only will the cabin crew not be able to tell whether someone's using a transmitter during the flight, neither will the people using them. Every electronic gizmo, whether it's turned on or not and whether it looks as if it will radiate or not, will have the ability to wake up and spurt something into the ether, of its own accord.
That's next year. Intel, bless, is already talking about building broadband wireless networking into every chip it makes -- as in every processor, memory chip, pc glue chip, you name it -- because it's close to making this a zero-cost option. This won't be for a couple of years. Maybe five.
The battle -- to make the cabin an RF-free or RF-controlled environment -- has already been lost. The only option is to think defensively, identify problems before they become critical with existing equipment and to design for the actual environment. The days when only policemen and radio nerds had portable transmitters died in the 80s.
R