Using ebook readers on aeroplanes?

[jbjb]

Originally Posted by ThomasMc

If that were true, as you claimed, about the Faraday effect cancelling them out, then it would also be true on the ground, and you would not be able to use your phone inside the fuselage there, either.

I'm afraid you've misunderstood.

Firstly, the effect of a Faraday cage isn't symmetrical - i.e. it protects things inside it from external electric fields, but a charge *inside* it will still generate a field outside it.

Secondly - the Faraday cage effect, which applies primarily to electrostatic fields, is not the same thing as electromagnetic shielding. Faraday cages, by their very nature, can have an RF shielding effect, but that's not really what is generally meant by the Faraday cage effect.

However - all this is largely irrelevant to the "turn off electronic devices" discussion. Faraday cage immunity to electric fields outside the aircraft is not related to immunity to RF radiation originating inside the aircraft.

/JB

[jbjb]

Originally Posted by ThomasMc

It has nothing to do with windows, Harry. An ungrounded Faraday cage is an antenna.

You're confusing the inside and outside of the Faraday cage. Clearly, the electrical potential of an ungrounded Faraday cage can vary with respect to ground, and hence it can be used as an antenna, while that of a grounded Faraday cage won't. However, that doesn't get around the fact that the electric field *inside* the cage will be zero in both the grounded and ungrounded cases.

Put a radio next to a metal window screen, and you'll get better reception. That was a trick I learned in the 70s, with my short wave radio. It isn't because the radio waves are passing through the little holes, they are smaller than the wavelength of the signal. Ground that screen, and you have the opposite effect, the signal is blocked from that direction, and you have a weaker signal.

That's got nothing to do with Faraday cages. A metal window screen is not a Faraday cage - it doesn't completely enclose the radio.

/JB

[GeoffC]

Originally Posted by ThomasMc

If that were the case, then why do pilots fly hundreds of miles out of their path to avoid electrical storms, and why do planes have dissipators, to eliminate the buildup of charges that might attract lightening? It is these two things that prevent lightening strike related crashes, not a Faraday effect.

because electrical storms imply active weather systems and passengers don't like being told to buckle up seat belts and planes don't really appreciate being tossed about overly much.

[Lo Zeno]

Originally Posted by GeoffC

because electrical storms imply active weather systems and passengers don't like being told to buckle up seat belts and planes don't really appreciate being tossed about overly much.

And also because inside an electrical storm the pilots risk to lose radio contact and be unable to comunicate with nearby airports because of signal interferences (also called radio noise).

[Shaggy]

Originally Posted by Lo Zeno

And also because inside an electrical storm the pilots risk to lose radio contact and be unable to comunicate with nearby airports because of signal interferences (also called radio noise).

Maybe the pilot could use their cell phone instead.

[B.Tackitt]

So far this summer I have flown from DFW to SFO and back 5 times with another 3 still to come. On only 2 of the flights were iPads & other e-reading devices mentioned.. on 1 of the flights one of the flight attendants was busy reading on her Nook, so I had no qualms about reading on my Kindle. On one flight they made an announcement that says "if it has an off switch..." so it went off. I just listen to what they say and tailor my actions to suit.
I do carry quilting handwork with me JIC.

[JaneD]

On my recent flight they said "turn off all electronic devices" without specifying ereaders particularly, but it seemed a broad enough to cover everything.

And yes, I turned off my kindle. And my blackberry, for what it's worth.

[kindlekitten]

my flight Sunday, Seattle to Phoenix, Phoenix to Albuquerque I very openly read my Kindle as the flight attendants went up and down the aisles doing the pre-flight checks. my seat mate was reminded to buckle his belt, nothing was said about the Kindle. my phone with the stupid touch screen was in my hip pocket and once again managed to turn itself on. plane took off and landed just fine. turbulence was a bitch though

[hangers]

just like ipod or mp3 player they asked me to turn it off . . . when i was travelling to brisbane . . . cause it's an electronic thing . . . WHATEVER . . . !!!

[GeoffC]

Originally Posted by hangers

just like ipod or mp3 player they asked me to turn it off . . . when i was travelling to brisbane . . . cause it's an electronic thing . . . WHATEVER . . . !!!

just a thought .... poor one .... is a pacemaker electronic ?
They don't worry about hearing aids ... mmmmm

[niggle]

Originally Posted by GeoffC

just a thought .... poor one .... is a pacemaker electronic ?
They don't worry about hearing aids ... mmmmm

Both Cathay and Singapore airlines have told me to turn off my oxygen concentrator for take off and landing on flights from Aus to Asian destinations (I have Emphysema due to alpha-1 deficiency). I have to say that I'm less concerned about being told to turn off my Bebook or Ipod for 10 or 15 minutes.

[mogui]

This thread has the potential to be useful rather than merely titillating. But first we will need additional categories. Pretend you are wishing to fly somewhere, say, Thailand. You look for airlines that fly to that destination and find, perhaps, Air China, Thai Airlines, and Korean Air. Next you look on their websites to ascertain their respective electronic-gadget-in-flight policy.

What? They don't offer any information? So you must buy a ticket and take your chances. I did this. I found these policies in the Mabuhay in-flight magazine of Philippine Airlines:

ELECTRONIC EQUIPMENT
In the interest of flight safety, all transportable electronic equipment are not to be operated during take-off, climb-out, descent, final approach and landing, except for personal electronic life support systems.

Electronic devices which intentionally transmit radio signals should never be used for the whole duration of the flight. These include, but are not limited to: radio transceivers, CB radios, cellular phones, and electronic remote control transmitters.

Transportable electronic equipment which are non-transmitters and without any accessories that would transmit/receive radio signals, such as laptop computers without WiFi and wireless peripheral devices, video cameras/players, tape recorders/players, CD/DVD/MP3 players, calculators, electronic entertainment devices and electronic shavers maybe used after the safe use of these has been announced.

Some flight conditions may require the discontinuance of the use of electronic devices and will be announced by the crew.

Personal electronic life support systems such as hearing aids, electronic nerve stimulators, respirators may be used throughout the flight.

Notice that your laptop with Wifi is prohibited even if you have the WiFi off. This goes for readers too. I have colored the text above as it appeared in the in-flight magazine.

I do not argue with the attendants. A modern aircraft is a complex piece of electronic gear. Many of the controls are fly-by-wire with signals being carried over one or more networks. Signals that guide and control the aircraft are also broadcast outside the aircraft. Any chance of electrical interference could be catastrophic.

Back when automation was taking over in the airline industry it was said they were hiring big dogs as co-pilots. The computer flew the aircraft. The pilot watched the computer fly the aircraft. And the dog bit the pilot if he dared to touch the controls.

With takeoffs, landings and in-flight navigation left up to electronic devices, do you want to make the judgment about what devices are safe or not? Or would you leave it up to the designers and the aircraft crew?

Now perhaps if we had a section of the forum or the wiki that documented airline electronic use policies, categorized by airline, we could decide which ones to fly on. Personally I take it as an opportunity to engage in nostalgia. I take along a paper book. You can still find them in some dusty used book stores.

[hols57]

Originally Posted by GeoffC

just a thought .... poor one .... is a pacemaker electronic ?
They don't worry about hearing aids ... mmmmm

...God, I hope not! It's bad enough being hard-of-hearing without having to worry about bringing down the plane by keeping my aid switched on!!!

[SeaBookGuy]

When I travel, I bring along a print book classified as "takeoff, landing and breakfast" (I'm not leaving my e-reader on the table, nor bringing it with me to the buffet line).

[whitearrow]

Originally Posted by mogui

Notice that your laptop with Wifi is prohibited even if you have the WiFi off. This goes for readers too.

I don't read that the same way you do. To me, if wireless is turned off, the device is not "intentionally transmitting" signals.