View Full Version : Mobile phone use
modelman
2nd Mar 2006, 22:08
Been following another thread on radio failure :( and noticed comments 'call up the airfield on your mobile'. I understood the use of a moby was illegal in the air.( even so,seems a better idea than orbiting trying to get ground control to realise your predicament).
Are you likely to get a knackering for use of the mobile when you book in?
Modelman
White Bear
2nd Mar 2006, 23:07
You have got to be kidding!
I have 2 mobile phones, one works when I’m flying, one doesn’t, guess which one I take with me?
Do you honestly believe anyone will question how you called the airport?
Regards,
W.B.
:ok:
HiFranc
3rd Mar 2006, 06:11
I haven't started my PPL yet nor read up on law. However, I suspect you'll find that it depends on the aircraft type (I may be wrong).
My understanding is that you are not permitted to use mobiles on modern passenger aircraft because the mobile phone signal could, theoretically, interfere with the guidance computers (especially on take off and landing).
{edit}Correction: I just remembered: it does interfere. I heard a tale from somebody who got a ride in a cockpit. The pilot demonstrated what happened when a mobile was switched on onboard -- one of the instruments showed a slight uncertainty in its reading. The theoretical part is that they could, potentially, cause the computers to make bigger errors.
2nd edit:
In an on-line IT magazine, there's a short report on the problem posed by mobiles in some aircraft (http://www.theregister.co.uk/2006/03/02/aircraft_mobile_phone_risk_study/).
This one will run and run, due to lack of evidence.
Firstly, a mobile phone (when not used for calls/texts) transmits only about every 10 minutes, and this happens only if connected to a network. Plus very briefly when it is switched off, and when it first connects after being switched on. So any sort of continuous interference seen will be from something else, or from somebody making a call.
Secondly, any plane that is affected to the degree some fear is going to crash - simply because, short of a strip search of everybody, one cannot guarantee there are no phones accidentally left on. I bet every 747 is packed with phoned that are left on. The systems must be designed with better immunity than that.
The issue with messing up the network is a separate one. It seems to work OK however, perhaps because not many people do it. I normally find mobiles work OK below about 3000ft but I use them for texts only.
Some time ago I used a Nokia 6210 as a GSM modem (9.6k) for internet access, with a PDA, to get weather while airborne. It actually worked once over France at about 8000ft but it was never much good in the UK above about 2000ft. The TCP/IP connection would break after a minute or two in any case. GPRS is a dead loss.
So I would not rely on a mobile for a speech call, in any airborne circumstances.
I did a bluetooth search from my laptop on a commercial flight the other day and was presented with a list of half a dozen mobile phones. Keeping in mind that lots of people don't have bluetooth turned on even when their phone is and it only works for 30 feet or so there were probably 50 or more phones turned on.
Oxeagle
3rd Mar 2006, 08:22
I'm not too sure about the effect on aircraft instruments, but I recently did my Air Law exam and remember it mentioning in the book about airborne mobiles making other mobile users disconnect from their calls and potentially crash the mobile network in the local area!
From New Scientist (http://www.newscientist.com/channel/info-tech/mg18725161.600.html), 10 September 2005:
THE US Federal Communications Commission (FCC) bans cellphones from aircraft because the airborne signals can clog up base stations over a wide area.
The problem occurs because of the way cellphones work. Cellphones on land can normally hear around three or four base stations, and remain registered simultaneously with all of them. This takes up a slot on each base station, and there are only so many slots to go round. On land this is normally not a problem as buildings and terrain usually mean the number of phones within sight of a particular base station is manageable.
However, phones in an aircraft are likely to have line-of-sight contact with scores of base stations, so they will use up slots in many more base stations than the designers of the network intended. Fly a plane full of handsets over the same area and you will soon clog up the base station registers, jamming the network. Hence the FCC's ban.
LowNSlow
3rd Mar 2006, 09:03
I tried it once but gave up for two reasons:
1. The signal kept cutting in and out rapidly (I was at around 2,500' agl) as I passed over the base stations.
2. The Auster cockpit is so noisy (four open exhaust stubs :eek:) that I couldn't hear anything when did get through!
Papa Bravo Delta
3rd Mar 2006, 09:41
When I was learning I phoned up my instructor on his mobile. When he answered I said "there's a lot of noise in the background, where are you?"
He said "base leg" !!!
This is the AIC on the matter (AIS Registration required):
http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4P062.PDF
Although it would appear to be directed at Public Transport operations.
James Bond
3rd Mar 2006, 11:46
Oxeagle, a friend of mine, an instructor at Welshpool a few years ago, got a very snotty letter from Orange I believe, asking him not to use the phone whilst flying as he had crashed the whole network on several occasions. The next time it happened I think they threatened him with a large bill for resetting the network...
Steely Eyed Missile Man, (Stu) are you out there?? :ok: :ok:
LFS
Yes, somebody wrote that guidance paper up for airlines. It isn't based on anything scientific that I can see. The usual CAA stuff.
JB
I can't believe you joined in Feb 2006 yet that name has been unreserved all that time!!!
Anyway, when did this happen and is this first-hand i.e. did you see that letter? The reality is that there are hills around Welshpool that are as high as a lot of people fly at, and I have not heard of a ban on hill walking while carrying a mobile phone.
n5296s
3rd Mar 2006, 16:11
For sure a phone in an aircraft can "see" far more base stations than the system was ever designed to be able to cope with. If it "crashes the network" though then there is something seriously wrong with the network! At worst it would cause interference to some other calls.
The other day I was on Mount Hamilton, just SE of San Jose at 4400' with a fantastic view over the whole south bay and Santa Clara valley. I tried to use my phone. It showed a good signal (no surprise) but every time I tried to make a call, it failed and showed no signal for a few seconds. Similar phenomenon I guess.
Of course 4400' is a lot higher than you normally get to fly small planes in UK airspace...
n5296s
The reality is that there are hills around Welshpool that are as high as a lot of people fly at, and I have not heard of a ban on hill walking while carrying a mobile phone.
I asked that very question of a tame(-ish) telecoms engineer. His response was that the antenna siting patterns are based on local topography, so the cells 'know' when a phone is likely to be in line of sight of more than one of them.
Also, he made some smart@rsed remark about hills not moving about very much. :hmm:
Hills not moving about? Cars can and do move faster than most GA spamcans, yet the phones in them are supposed to still function.
172driver
3rd Mar 2006, 21:19
Hills not moving about? Cars can and do move faster than most GA spamcans, yet the phones in them are supposed to still function.
Yes, but from the air your phone has a much larger 'footprint' than from the ground. The whole issue has been discussed ad nauseam - it's a mobile network problem, no more, no less.
The cars may move about, but the roads on which they are driving do not.
AIUI, at any spot on that road, the number of cells visible in line of sight will be limited and topography considerations of network design takes that into account.
Send Clowns
3rd Mar 2006, 23:13
n5296s
Switch off your battery saving mode, if it is possible on the phone. The handset gets a good signal, so it reduces its own output on the assumption that you are near a base station, but you aren't! I have done this from the Brecon Beacons in South Wales, having hte same problem, and it worked.
IO540
Did you pay attention to your groundschool? 1.25 x square root of height in feet? And what type of aircraft are you flying in? OK, not the 160 kts TAS I usually flight plan, but most travel at 120 mph or so, enough to get a long ban even on the motorway! How many people phone at such speeds in cars?
I plan for 160kt+ TAS too, but my point was a general one: people can and do drive at 100mph+ and if every time their hands-free kit (if indeed they have one) accepted an incoming call the whole network got overloaded and crashed, there would be major problems. And network coverage does have to be very good around major roads - that is where the companies concentrate first (for travelling businessmen).
So I think a much bigger meal is made of all this than is necessary.
My phone can be put on airplane mode, whereby all network connection gets cut off. Leaving no intereference, and me happy to play my games and even take videos of landing :cool:
India Four Two
5th Mar 2006, 21:28
Just to add a little fuel to the fire, here in Canada, we are encouraged to use mobile phones in the event of a radio failure:
5.15 Phone Use During a Radio Communications Failure
Paragraph 5.11 outlines the procedures for emergency communications using very high frequency (VHF) channels.
NAV CANADA publishes the phone numbers of ACCs, control towers, and FSS units in the Canada Flight Supplement.
In the event of an in-flight radio communications failure, and only after normal communications failure procedures have been followed (see RAC 6.3.2.1), the pilot-in-command may attempt to contact the appropriate NAV CANADA ATS unit by means of a phone. Before the pilot begins using a phone to contact ATS in the event of an in-flight communications failure, transponder-equipped aircraft should squawk Code 7600 (see RAC 1.9.7).
http://www.tc.gc.ca/CivilAviation/publications/tp14371/COM/5-0.htm#5-11 (http://www.tc.gc.ca/CivilAviation/publications/tp14371/COM/5-0.htm#5-11)
englishal
5th Mar 2006, 22:00
It is only ILLEGAL to use a mobile phone in flight when the aircraft is flying IAW IFR or in otherwords on an IFR flight plan.
FullyFlapped
5th Mar 2006, 22:55
I'm sure I'm going to get the mickey taken for asking, but there again I've been ... erm, socialising ... for the last few hours ;)
What is "IAW IFR" ?
FF :ok:
GSM "shares" the channel between several phones, using "time division multiple access". Your phone has a very short "timeslot" when it can receive, and another when it can transmit. If you are over a certain distance from the base station (something like 18km IIRC), your transmission will be out of timeslot and despite an apparently good signal, your phone won't work.
Out in rural parts, the timeslots are "double size", allowing greater distance.
You might be able to make a call while airborne using a GSM phone, but it's likely to be problematic.
Also, the phone will watch the local cell sites, and try to negotiate with a new cellsite if it thinks it should. That's the "burp burp di burp burp" you hear sometimes. Whenever I've forgotten to turn off my phone before flying, I hear that in the headphones within a minute or less of takeoff. Once, I noticed the ILS needles having a fit at the same time. Once I turned the phone off the ILS was fine.
Edit: IAW IFR - In accordance with instrument flight rules.
FullyFlapped
6th Mar 2006, 09:22
Edit: IAW IFR - In accordance with instrument flight rules
Ah, I see.
TVM - YVK.
(Thanks very much - you're very kind). ;)
FF :ok:
Lister Noble
6th Mar 2006, 10:14
Ah, I see.
TVM - YVK.
(Thanks very much - you're very kind). ;)
FF :ok:
How's the head?
Lister:D :D :D
FullyFlapped
6th Mar 2006, 15:49
Still attached, thanks, Lister, and now the "inner turbulence" has subsided, things are looking up !! :) :) :)
FF :ok:
I think this is one of those topics that will go on forever, just like the 'Does the use of mobile phones cause brain tumours' or 'does living near phone masts/pylons cause other life threatening illnesses?
Well, I thought I'd present evidence for and against such claims.
Against:
Mobile phones world wide operate on either 900 or 1800 MHz (not sure about new services such as 3G), with the exception of the U.S. where they operate on 1900 MHz. A/C systems operate on KHz (HF Radio, NDBs etc), between 108 and 118 MHz ((I think) for VORs/ILSs) and between 118 and 135 MHz (VHF Radio). So how can signals with a difference of more than 700 MHz between them interfere with each other?
For:
Yes, mobile phones do emit signals. Every few minutes they send out a signal to the network to say, 'hey, I'm still here' and the network acknowledges that. I generally find that in the UK, you loose your signal at about 1000' agl. I know this varies from country to country as my phone started ringing at 10 000' when gliding in Australia! The trouble starts when the phone looses it's signal. It starts sending out more and more signals trying to re-establish itself on the network.
I think the switching off the phones thing comes from the phone networks. If you're at say, 3000', chances are your mobile's in contact with two or more base stations - which the networks dont like. I too have heard of people with rediculously large phone bills because of this. Doubtful if this would happen at 35 000' or so. I also think that airlines get you to switch off you phones is so that it's one less distraction during safety briefs.
I also know a few avionics technicians who also say that there is no way mobiles can interfere with A/C systems.
Hope i've added some fuel to this ever burning fire :)
HiFranc
8th Mar 2006, 06:33
I think this is one of those topics that will go on forever, just like the 'Does the use of mobile phones cause brain tumours' or 'does living near phone masts/pylons cause other life threatening illnesses?
Well, I thought I'd present evidence for and against such claims.
Against:
Mobile phones world wide operate on either 900 or 1800 MHz (not sure about new services such as 3G), with the exception of the U.S. where they operate on 1900 MHz. A/C systems operate on KHz (HF Radio, NDBs etc), between 108 and 118 MHz ((I think) for VORs/ILSs) and between 118 and 135 MHz (VHF Radio). So how can signals with a difference of more than 700 MHz between them interfere with each other?
Not directly but think of this:
1800 MHz is 1.8 GHz
If the computer which is processing that signal has a 1.8 GHz chip then it can, in theory, interfere with the chip's processing of the signal.
mad_jock
8th Mar 2006, 19:17
From personal experence they can cause certain systems to indicate when you don't want them. eg hold fire detectors. nothing in GA aircraft although what it does to modern electronic machines I don't know.
After working for the great swedish 3 sausage company I was more to do with the IT side of things not the internal workings of the MSC and BSC's. 3G just piggybacks on the old feqs.
The problem with multiple registrations with base stations was solved quite a few years ago. It created multiple signals which wouldn't be closed and occasionally hung the exchange if it wasn't spotted. The quick fix was to give it a "small". They used to get it next to the high speed railway tracks in europe and bullet trains in Japan. Although I should imagine a few heavys all coming into range at the same time may cause some problems with multiple registrations but it wouldn't cause the exchange to crash the BSC would load limit and kick off all the pay as you go. I have seen the test engineers try and crash a switch, they had multiple WAGO units on and they were generating millions of registrations and call setups every second. And it was coping well in excess of the design limit.
The causing headaches / cancer and other problems is a rather touchy problem, shall we just say smoking and the corp liability and the implications of admitting liability and leave it at that. Alot of people at the 3 sausage firm ended up refusing to use a local cell setup due to health concerns and started using land lines again. Apparently since the blue tooth cyborg hand free kits have been in the market place and generally used by high usage users it has been swept under the carpet again.
Would I endevour to have my mobile off on a commercial aircraft. Yes
In a light aircraft flying VFR, nope I wouldn't be concerned. The most dangerous situation I have had in a Light aircraft due to a mobile phone being on was when it went off with the vib alarm on in my pocket at 5ft in the flare.
But on the plus side i have been cleared into controlled airspace to land with a radio failure.
But it's common sense if everything is going great have it turned off so you don't get noise in your headset, and the battery actually has some power in it when you land. If you have a radio failure turn it on and use it as a tool to improve safety.