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-   -   mobile phones (https://www.pprune.org/passengers-slf-self-loading-freight/500963-mobile-phones.html)

GrahamO 11th Dec 2012 18:31

The airlines own the aircraft so we should respect the rules under which we are permitted to fly with them - and no excuses.

I do however think that the danger is massively hyped, and if aircraft are that sensitive to the emanations of a mobile phone with extremely low power, flying in a spectrum which is saturated by many orders of magnitude more of transmissions from the ground, then they should be dropping out of the air every day.

Yes, I am an engineer with a communications background. I am more worried about a drunken pilot than a stray mobile phone.

TightSlot 11th Dec 2012 19:49

For what it's worth, I would agree that the problem is over-hyped. One thing to remember though is that there may be a difference between the effects associated with up to a dozen mobile phones inadvertently left on and 330+ deliberately left on.

For the time being, the regs say no, although change is in the air (boom-boom).
For the meantime, I remain fascinated that so many people can become so massively cross because they are unable to use their phone for a few hours, or in the case of pico-cell aircraft, for a few minutes on departure and approach.

I'm not being cute - It really is a mystery to me. I'm coming to believe that for some, any kind of restriction is an unacceptable imposition. As I get older and grumpier (it'll happen to all of you in the end, believe me) I find that there are more and more things, and people, that are genuinely unacceptable: The use of mobile phones is some way down my list and has several noughts after it.

GrahamO 11th Dec 2012 20:53

Some good point there Tightslot.

If the approval were to be granted, I think it would significantly improve the flying experience if passengers were only able to text and email/IM during the flight as it would mean most of them were silent throughout the entire flight.

You can cram an awful lot of email/text/IM on a small internet link but one loudmouth audio user could cause 'disruption' :)

ExXB 12th Dec 2012 06:49

TS, I see an aircraft equipped to handle connections with mobile devices to be better than one that isn't. In the first case the devices won't ramp up their power searching for a connection, in the second that's exactly what they do. (which is what happens when I forget my phone is on).

The airlines can limit the connections, if they choose, to text and internet but I don't think it's necessary as the cost per call is a major limiting factor.

Of course there are idiots who may disrupt a flight, but they will do so anyway. I was on a Squeezy flight the other day where a passenger was having a conversation with his buddy two rows back, shouting in dialect! One of the FAs asked them to be quiet during the safety briefing and they ignored him. They did this the whole flight.

I think it's ludicrous that on the BA LHR-SNN-JFK flight you can text and connect to the internet once at altitude, but they have to shut it down when the enter US airspace, long before they begin decent. Why is it OK in British, Irish, Icelandic and Canadian airspace but not in the US? (Rhetorical question).

People will leave their phones on, and some will try to use them, that is a given. Knowing that, regulators should be ensuring that the aircraft is as safe as possible.

radeng 12th Dec 2012 15:01

Texting can put up with the delay through a satellite. GSM for example, has a range limitation because of the time it takes the signal to reach the base station - from memory about 40 or 50 km.

Just to help matters, there are hearing aids with radio transceivers in them. I helped with systems engineering of an integrated circuit for that application, and also for radio transceivers in pacemakers - over 500,000 of them in use world wide. Bit hard to turn those off, of course, but the power is very low - in both cases, under 1 mW. Plus, if the pacemaker transmits while in an aircraft, it's because there's a cardiac emergency.

strake 16th Dec 2012 10:27


I'm not being cute - It really is a mystery to me. I'm coming to believe that for some, any kind of restriction is an unacceptable imposition. As I get older and grumpier (it'll happen to all of you in the end, believe me) I find that there are more and more things, and people, that are genuinely unacceptable: The use of mobile phones is some way down my list and has several noughts after it.
I think it simply comes down to restrictions people think are "fair and sensible" against those they don't - rightly or wrongly. For instance, sitting down on take-off and when landing is a "restriction" but people can obviously work out why they should do it. However, no matter how hard authorities try to say otherwise, the majority of people just don't believe a mobile phone (or indeed 200) can cause a serious problem to an aircraft's ability to operate. I've observed the restriction gradually being eroded in the USA. I'm absolutely sure that a good percentage of the people I watch texting and calling "before the door shuts", just put their phone away without turning it off and then pull it out again just after the wheels touch down.
I'm not suggesting it's acceptable, just my thoughts on why it's such an issue for some. For me, equally older and grumpier, I can't be bothered using the thing anyway and save my vitriol for important things like why do I have to spend 12 hours in the close company of people who invariably irritate me by being noisy, smelly, ugly or in fact, just "there"?
See, I told you I was grumpy.

radeng 17th Dec 2012 08:25

There is of course the point that you have no idea for any 'phone of where 'unwanted emissions in the spurious domain' fall in the spectrum, nor their level. Or even if the level meets the relevant standard (-36dBm below 1GHz, -30dBm above 1GHz) that it won't cause a problem.

Bill4a 30th Dec 2012 09:44

A couple of years ago BA from Gatwick to Izmir a cabin announcement was made along the lines of " will the passenger using his mobile phone please switch it off, we can hear your conversation!" Result - One very surprised and red faced Turkish businessman, who had 'forgotten' he couldn't use his mobile in flight. :ugh:

Sunnyjohn 30th Dec 2012 13:20


I remain fascinated that so many people can become so massively cross because they are unable to use their phone for a few hours
It seems to be almost an addiction. I read recently that young people (In Spain, that takes you up to age 50!) are unable to refrain from using their mobile devices for longer that ten minutes. And as for the number of people I nearly bump into because they are gazing at the things . . .

Off- thread, and apologies mods, but yesterday I saw the lot. A chap on a bike riding no-hands with one hand working his mobile and an iPod in his ears. The other hand was in his lap but I couldn't see what that was doing! No wonder they get killed on level crossings.

CafeClub 10th Jan 2013 00:58

Apart from having to listen to someone discussing their irritable bowel syndrome aside, mobile phone use (and implications on safety) in flight is one of those rules that is a "we don't know so....."

Thing is it is not cut and dried. Having flown a lot in Asia especially the subcon, IF mobiles impacted flight systems, then aircraft would be falling out of the sky like flies. Fact is they are not. The number of phones chirping and cheeping as you descend into (say) Mumbai is pretty amazing.

The FAA is unsure too...

Are Cell Phones Dangerous In Flight? (VIDEO)

And with people like EK allowing in flight usage....

So next time, before you get all panicky while sitting on a DASH and some teen is sexting his/her friend, just plug your ipod in and listen to some soothing music.

radeng 10th Jan 2013 08:48

You only need ONE incident......As a professional radio engineer, involved with EMC and having worked on mobile phones amongst other things, I KNOW that there is a finite possibility of them causing a problem. There's always a number of people with little or no knowledge of the technology who think they know best. They get away with it for a time......

Tableview 10th Jan 2013 08:50

Electronic devices on planes: Turn off your iPad now, please | The Economist

Hartington 10th Jan 2013 15:29

It's only just occurred to me that I wear one of those watches that get their time on a long wave frequency from various transmitters round the world. I'm told it wakes itself up around 2 in the morning, verifies the time and then goes back to sleep.

Quite apart from how many more people wear those I wonder how many other low power radio devices people bring on board.

Tableview 10th Jan 2013 16:05

Those radio-controlled watches/clocks are passive (i.e. non-transmitting) devices and should not pose any risk.

radeng 10th Jan 2013 17:28

They do some radiating, but it is much lower power - partly because you don't want to run down the battery.

t1grm 10th Jan 2013 17:37

Here's an interesting variation. We've just been asked to switch mobile phones and all electronic devices off during refuelling (at the airport doors open). What's that all about then? Can electromagnetic waves ignite jet fuel as well now?

CafeClub 10th Jan 2013 17:56

I think it has been tested enough. :E

Lets use india for example. Say 1500 flights a week domestically? 300,000 pax? Even if just 5% of the weekly 2.1 million pax left their phone/ipad/gps/nintendo turned on, that's still over 100,000 mobile devices buzzing away on planes every week for what, the last 5 or 10 years?

And that's just beer coaster calc. Anyone who has flown in the subcon knows that it would likely be many more per aircraft than 5%, and then add Africa, China, Russia, and those recalcitrant travelers on Air Canada... :rolleyes:

All on every version of every aircraft type, all using a multitude of transmitting devices...

How many have plummeted earthwards? None that i am aware of. :oh:

I was one of those that religiously turned mine off, but now it is an afterthought. If there is a serious, burn in purgatory risk, then at security they would be binned, disabled and their owners would have their cavities searched. :\

And pprune would be full of news of the latest crash caused by a sexting teen.

Instead, the onus is on the airline, who in turn dump this task on the hapless cabin crew, who after surviving a few dozen flights where phones have been on, probably get tired of starting their work with an argument with a phone user. :ugh:

I say again, plug in your ipod and worry about other stuff, like which movie you are going to watch off the rack of electromagnetic radiating hard drives in the IFS.:ok:

Capot 10th Jan 2013 18:11

Quote from that Economist article...


at that point the prospect of taking a cut of the sky-high calling charges will miraculously cause our safety concerns about mobile phones to evaporate.
Or, last time I flew on Norwegian, the airline's wish to offer a fantastic, free, wifi service on board, to which one's mobile/smartphone/tablet/laptop/netbook/whatever can connect when switched on and not in "Flight Mode", for the the benefit if its customers, and of course to attract them in the first place.

The service terminated at 10,000ft, but I understood this was not for safety but to allow CC to get the cabin in shape for landing.

Presumably EASA, Boeing, and the Norwegian CAA, to name but a few with the power to prevent this happening have not found a need to do so. And so far as I know the new Norwegian Boeings do not have special wiring and electronics protected against mobile phones etc.

radeng 11th Jan 2013 08:56

CafeClub:

How many 777 flights had there been before YMMM?

t1grm

There are some British Standards for the RF intensity level allowed before ignition occurs, based on some Sheffield university work. There's also a DEF STAN on allowable RF levels around munitions and fuel - I can't remember which one, and I'm not at home to look it up. But it's lot higher than you get from a mobile 'phone. The limitations you see on garage forecourts around petrol pumps came from the discovery by illegal CBers running around 50 or 100 watts led to the petrol pump under registering, rather than ignition problems.

It's thought by many that an arc can cause ignition, but in fact, the arc has to have a certain amount of energy, depending on air/vapour mix. Unless there is enough energy, it won't catch.

More of a problem, is that the person using the 'phone gets distracted and does something silly (like texting while driving!), or if the thing is dropped and the battery sets fire to some of the bits, maybe because of a short circuit.

Rawtenstall 11th Jan 2013 17:06

coming home on a flybe flight after christmas, my daughter was reading her new iPad, in flight safe mode. When the "10 minutes to landing" announcement was made she turned the device off by pressing the button on top of the device, and the screen turned off. However a passing flight crew saw this and insisted that the device be fully powered down. We didn't really know what she was on about, the device was turned off, but the stewardess made a point of showing us that we had to hold down the top button then slide the icon that appeared on screen.

So when is "off" really "off" with these gadgets - when the screen is black or with a full power down?


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