Mobile Phones
Joined: Aug 2011
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From: Jupiter
I'd say whilst flying VFR the risk is so minimal as to be non-existent. No-one seems to have been able to demonstrate any sort of interference, but even if there was some small effect then it shouldn't endanger a VFR flight. As someone else said, you hold your heading by looking outside.
I've found the practical altitude limit to be about 2,500 ft. But I'm sure it depends on the network, the model of phone and the location. So if any LARS unit wonders why someone reports descending 2,500 ft and then 2 mins later reports climbing back up then it was probably to get a text sent! :-)
The "tick, tick, tick" you hear when the phone is transmitting is not interference with the radio, it is the effect the phone has on the loudspeakers in your headset. You'll hear exactly the same thing if you place a phone which is 'doing something' near any other 'live' loudspeaker such as a small kitchen radio, a hi-fi, or indeed in the car. The ticking isn't a problem, it's just annoying.
I've found the practical altitude limit to be about 2,500 ft. But I'm sure it depends on the network, the model of phone and the location. So if any LARS unit wonders why someone reports descending 2,500 ft and then 2 mins later reports climbing back up then it was probably to get a text sent! :-)
The "tick, tick, tick" you hear when the phone is transmitting is not interference with the radio, it is the effect the phone has on the loudspeakers in your headset. You'll hear exactly the same thing if you place a phone which is 'doing something' near any other 'live' loudspeaker such as a small kitchen radio, a hi-fi, or indeed in the car. The ticking isn't a problem, it's just annoying.
Avoid imitations
Joined: Nov 2000
Aviation Qualifications: ATPL
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From: Wandering the FIR and cyberspace often at highly unsociable times
I flew one type of aircraft (helicopter, IFR twin, made in USA, quite a few of them about) for five years or so where a phone left switched on in the aft baggage bay would set off the smoke/fire detector. As the bay was not accessible in flight, and there was no fire extinguisher in there, there was no way of knowing if the warning was real or not. The required checklist drill was to land asap. Bad enough VMC but a big concern when IMC.
We obviously emphasised this issue to passengers during the safety brief.....
The aircraft manufacturer said they had found no problems on their side of the Atlantic. But of course their mobile phone network uses a different frequency band.
We obviously emphasised this issue to passengers during the safety brief.....
The aircraft manufacturer said they had found no problems on their side of the Atlantic. But of course their mobile phone network uses a different frequency band.
Joined: Jan 2011
Posts: 335
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From: New Zealand
this whole phone things B*LL*CKS
With the engine running and avionics on I showed a friend of mine what happens if i held my BB up to the VOR or NDB needles, nothing. near the radio, nothing not even interference on the headset. made a call to his phone. nothing.
I know thats not exactly a rigorous scientific test but seriously how is a bloke 10m back in business going to mess with the ILS when he's on the phone?
I think its more to do with paying attention to announcements etc while on board.
With the engine running and avionics on I showed a friend of mine what happens if i held my BB up to the VOR or NDB needles, nothing. near the radio, nothing not even interference on the headset. made a call to his phone. nothing.
I know thats not exactly a rigorous scientific test but seriously how is a bloke 10m back in business going to mess with the ILS when he's on the phone?
I think its more to do with paying attention to announcements etc while on board.
Joined: Jan 2011
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From: New Zealand
No i did this all on the ground.... don't like to be too distracted by doing this in the air.
I have had the phone in the cockpit and recieved many (missed) calls, (could not hear the ringer over the noise of the engine) and not noticed a blip. the radio by the bed tho, goes off when i get a txt!!
i think the sheilding is better in the cockpit.
I have had the phone in the cockpit and recieved many (missed) calls, (could not hear the ringer over the noise of the engine) and not noticed a blip. the radio by the bed tho, goes off when i get a txt!!
i think the sheilding is better in the cockpit.
Joined: Jan 2008
Aviation Qualifications: ATPL
Posts: 38
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From: The Smaller Antipode
Not totally relevant, but don't totally ignore interference from various sources, once had a compass problem on a 707, turned out it was a tape recorder - you know, the sort that were about the size of a portable typewriter and used reel to reel tape ( ask your dad ) - that had been loaded into the stowage above the seats - between two very large lines with the note : Do not load any electrical equipment here ! The permanent magnet in the loudspeaker was effecting some remote compass sensing stuff at that point.
Holding the phone near the ILS / VOR needles isn't the problem, hold the phone near the equipment that DRIVES those needles. Could be somewhere near where the phone is being used, as in my 707 case.
Murphy is always with us, but I agree, in small, VFR aircraft - no problem, just don't rest the phone on the glareshield, near the little compass suspended from the top of the windscreen !
Holding the phone near the ILS / VOR needles isn't the problem, hold the phone near the equipment that DRIVES those needles. Could be somewhere near where the phone is being used, as in my 707 case.
Murphy is always with us, but I agree, in small, VFR aircraft - no problem, just don't rest the phone on the glareshield, near the little compass suspended from the top of the windscreen !
Joined: Jan 2011
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From: New Zealand
I take ExSp33db1rd's point, but the phone was in between the 'dail' and the radio stack.
Also those magnets were huge, and certainly can do some damage, i'm an IT geek by trade and have seen Harddrives sitting on large speaker stacks wiped (certainly corupted) by the magnets they contain.
As for the Mag Compass i was told don't even leave car keys near them!!!
Also those magnets were huge, and certainly can do some damage, i'm an IT geek by trade and have seen Harddrives sitting on large speaker stacks wiped (certainly corupted) by the magnets they contain.
As for the Mag Compass i was told don't even leave car keys near them!!!
Thread Starter
Joined: Nov 2008
Posts: 118
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From: Suffolk
How high will a cell phone work at? It can be a lot higher than the expected 2 to 3 thousand feet.
According to studies carried out in Canada for a single engine light aircraft it is possible - with great tenacity in the face of repeated failed call attempts - to get through up to around 7000ft or so http://physics911.net/pdf/Achilles.pdf As height increases the probability of getting a connection linearly decreases until at around 7 to 8 thousand feet it reaches zero.
According to studies carried out in Canada for a single engine light aircraft it is possible - with great tenacity in the face of repeated failed call attempts - to get through up to around 7000ft or so http://physics911.net/pdf/Achilles.pdf As height increases the probability of getting a connection linearly decreases until at around 7 to 8 thousand feet it reaches zero.
Joined: Jun 2003
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From: EuroGA.org
It depends on where you are relative to the towers.
In the UK there is rarely a signal above 2k-3k.
In southern France, near the mountains, I was able to get a dial-up data call (for internet weather) at 8k. The call lasted maybe a few minutes.
I assume they had towers high up. In 2002 I saw people using mobile phones on top of Mt Kinabalu in Borneo after walking up there; 16000ft.
Never tried voice calls...
In the UK there is rarely a signal above 2k-3k.
In southern France, near the mountains, I was able to get a dial-up data call (for internet weather) at 8k. The call lasted maybe a few minutes.
I assume they had towers high up. In 2002 I saw people using mobile phones on top of Mt Kinabalu in Borneo after walking up there; 16000ft.
Never tried voice calls...
Joined: Jun 2007
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From: Swindon, Wiltshire
From two miles away (horizontally), you could get a perfect signal. At just a few hundred meters directly above the cell, you'll get nothing.
Joined: Jul 2005
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From: SoCal
In southern France, near the mountains, I was able to get a dial-up data call (for internet weather) at 8k. The call lasted maybe a few minutes.
I assume they had towers high up.
I assume they had towers high up.
Disclaimer: I am not a mobile phone engineer, the above from personal experience and reading a couple of articles on the subject.
Thread Starter
Joined: Nov 2008
Posts: 118
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From: Suffolk
Based on this discussion I have put together a short proposal for a simple check that a pilot could use to identify any very obvious interference in a GA aircraft's avionics. Assuming forewarned is forearmed I thought this might help manage down the risk from using the phone if it was necessary to make a call while operating the aircraft.
The proposal is a set of PowerPoint slides that I have loaded onto Facebook as an album at Mobile Phone Check | Facebook
The proposal is a set of PowerPoint slides that I have loaded onto Facebook as an album at Mobile Phone Check | Facebook
Joined: Feb 2003
Posts: 1,486
Likes: 7
From: Darwin
Plenty of headsets out there that connect to phones - and they're brilliant for getting AWISs from airports that for some bizzare reason have AWIS/AWIB available only by phone, not NDBs.
Also brilliant for mobile internet to get updated weather, weather radar, and submitting amended flight plans on the fly (so to speak).
Phone technology in Australia varies with the network. If you have a GSM phone, it won't work about about 3000 feet, but NextG antennas are not shielded downwards, so they work great at altitude.
Personally, ive made voice calls as high as 10,000 feet, and used mobile internet as high as 14,000 feet.
Also brilliant for mobile internet to get updated weather, weather radar, and submitting amended flight plans on the fly (so to speak).
Phone technology in Australia varies with the network. If you have a GSM phone, it won't work about about 3000 feet, but NextG antennas are not shielded downwards, so they work great at altitude.
Personally, ive made voice calls as high as 10,000 feet, and used mobile internet as high as 14,000 feet.
Joined: Apr 2002
Posts: 680
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From: Who cares? ;-)
Ther biggest issue and one the mobile phone companies do not like is when you are at altitude, your phone possibly can "see" and "be seen" by several base stations, all of which will try and respond to the handset! This can cause confusion on the network if a single handset suddenly appears in more than one location on the network!
I do know that some pilots got their mobiles blocked from the service provided because they were disturbing the network. It is NOT always what happens on the plane that the deal is, there could be other reasons for having them forbidden.
