Naked Science Forum
General Science => General Science => Topic started by: neilep on 24/07/2007 14:29:16
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I have found out recently (from this site that I can recommend http://www.thenakedscientists.com ..they have a forum too...also, I later discovered a chappy called Dr Chris actually has written a well good article http://www.thenakedscientists.com/HTML/articles/article/howdothunderstormswork-2/)...anyway...as you may be aware they insist you turn offyour phones when flying......so how does a plane cope when it's travelling through a greatr big battery of a cloud ?
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Dearest Neil of excellent post (Neil, praeclarus stipes )
Protection begins with the fact that airliners, and the majority of other airplanes, are made of aluminum, which is a very good electrical conductor. A lightning bolt's electricity flows along the airplane's skin and into the air.
There used to be the problem that lightening could cause a spark, and ignite the fuel tanks. In December 8, 1962 lighting did hit a Pan American Boeing 707 in a holding pattern over Elkton, Md. The lightning caused a spark that ignited fuel vapor in a tank, causing an explosion that brought the plane down, killing all 81 aboard.
This led to rules requiring that airplanes have built-in systems that ensure that a spark will not ignite fuel or fuel vapors in tanks or fuel lines.
As for why phones are banned on airplanes. Well, they just want you to use the expensive on board phone with your master card.
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Dearest Paul of equally and in fact even more so of excellent postage goodness and luff (Paul, discloure vindicatus benefactorus)
Thank you for this.
But what about the windows ?...doesn't some of the zillion volts seep in through there !)
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As for why phones are banned on airplanes. Well, they just want you to use the expensive on board phone with your master card.
There has been all sorts of nonsensical paranoia about mobile phones being dangerous on garage forecourts, hospitals, in aircraft, etc.
It was all nonsense, and gradually the restrictions are being reduced as people realise that when phone users break these taboos the world does not collapse in a heap.
There are two problems that do exist with using mobile phones in an aeroplane. Firstly, signal reception from within an aluminium tube is not going to be easy, and this will get worse as you get off the ground, and line of sight out of the cabin windows is just clouds and space.
Secondly, even if the signal does reach the ground, it will be difficult to localise it to a single cell on the ground (what weak reception there might be could be detected over hundreds of different cells, and the system will have to work out which cell to select - this made worse by the speed at which you are moving cell to cell, as well as the Doppler shift caused by that speed.
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Thank you George.
I agree completely about the inflammatory nonsense that using a mobile phone in any number of establishments is going to lead to a meltdown.
Presumably then phones that you can indeed use on a plane must use a different antenna array/transmission and reception system altogether.
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Thank you George.
I agree completely about the inflammatory nonsense that using a mobile phone in any number of establishments is going to lead to a meltdown.
Presumably then phones that you can indeed use on a plane must use a different antenna array/transmission and reception system altogether.
The planes themselves use satallite phone rather than terrestrial mobile phones (not may terrestrial mobile phone cells to be found in the mid Atlantic).
What I think they are moving towards is having mobile phone cells within the aircraft itself, so that your ordinary GSM phone will talk to the aircraft's own system, which then relays it to the satellite (and adds a hefty premium to your phone charges).