Mobile phone use
Joined: Jun 2002
Aviation Qualifications: PPL
Posts: 7,177
Likes: 297
From: Nanaimo (CAC8)
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:
http://www.tc.gc.ca/CivilAviation/publications/tp14371/COM/5-0.htm#5-11
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).
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
Official PPRuNe Chaplain
Joined: Apr 2001
Posts: 3,498
Likes: 0
From: Witnesham, Suffolk
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.
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.
Joined: Mar 2006
Posts: 79
Likes: 0
From: South Staffordshire, UK
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
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
Joined: Feb 2006
Posts: 37
Likes: 0
From: Newcastle upon Tyne, UK
How
Originally Posted by A V 8
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?
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?
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.
Joined: May 2001
Posts: 10,804
Likes: 1
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.
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.
