Mobile phone when airborne

[thing]

I have an iPhone5 with Skydemon. I use it as my default GPS as it's small, I can clip it to my kneeboard, it has built in GPS and works a treat (I carry two others GPS's as well). I don't use the phone to make calls or anything when airborne but obviously I can't have it in airplane mode as the in built GPS wouldn't work. What's the score on using these from a legal point of view re jamming masts etc? I can't imagine Skydemon releasing an app for the iPhone if it wasn't above board.

[Monocock]

I frequently text an ETA to my hosts when flying on a longish trip.

Jamming masts? I don't really care if it does! I pay £40 PCM for my contract and if I can't use it during my day to day living that's their problem.

Is it safe?

Well, a 5 second text and then reverting to true VFR IMHO is much safer than having one's head glued downhill for hours on end to an iPad with SkyDemon installed, like some people seem to choose to.

[thing]

Mmmm, back to the original question...

[Monocock]

No,

Using an iPhone based GPS app will not jam masts.

[thing]

Thank you.

[Mach Jump]

....obviously I can't have it in airplane mode as the in built GPS wouldn't work.

Are you sure your phone's GPS won't work in Flight Mode? My Android phone works fine as a moving map GPS in Flight Mode. Maybe it's just an Iphone thing. :sad:

MJ:ok:

[piperboy84]

I mostly fly in the late afternoon/early evening so leaving the phone turned on and in normal mode is a must in case any friends or family are calling around trying to organize a Salvador.

[thing]

Are you sure your phone's GPS won't work in Flight Mode?

No, you get the orange plane of doom instead of the yellow plane of hope.

[fireflybob]

On a legal point I understand using a mobile phone may contravene the Wireless Telegraphy Act since all transmissions from an a/c should be from an approved installation - which a mobile phone is not.

There is also a potential distraction factor if it rings whilst in a critical stage if flight.

[thing]

There is also a potential distraction factor if it rings whilst in a critical stage if flight.

You mean you can actually hear your mobile phone ringing in flight? Are you a glider pilot?

[RTN11]

So basically iphones are rubbish, if you just get an Android phone then the GPS works just fine in flight safe mode.

I often forget to turn mine off, worst case is the annoying electronic noise on the intercom, can be quite embarrassing if it does that while you're making a call to ATC.

As for jamming the masts, I don't think it creates a massive problem from the low levels of a few thousand feet, after all you could be up a hill and be that high, my understanding is that it's a problem when well in excess of 10,000' and you end up in a "white zone" where you can connect to multiple masts at once which the system wasn't designed for. I although I also hear that the more modern systems are fixing this, pretty sure we'll all be able to make phone calls on passenger flights in the not too distant future.

[Jetblu]

How do you lot get a mobile service when airborne?

I lose service climbing through 100ft.

[fatmanmedia]

On a legal point I understand using a mobile phone may contravene the Wireless Telegraphy Act since all transmissions from an a/c should be from an approved installation - which a mobile phone is not.


My understanding is that it's not illegal, otherwise pilots who have lost comms in flight who then decide to use a mobile to communicate with people on the ground would have been prosecuted before now.

Fats

[Romeo Tango]

With GSM there is a problem in that the protocol assumes the signal takes less than a certain time to go between mast and phone. If the signal takes too long it does not work. I seem to remember the maximum distance is ~15NM.

So when airborne one's phone may try to communicate with a mast more than 15 miles away and then give up completely even if there is a mast closer.

In my experience flying at 2500' or so results in an intermittent connection. Sometimes one can have a proper conversation with a bluetooth headset but expect to be dropped any time. It is usually possible to get a text out but it may take several tries.

The GSM modem in an iPad gives weather/NOTAM updates via Skydemon .... but again intermittently.

[Victorian]

The actual behaviour varies according to where you are. As stated, above 1500' or so in UK usually means no connection. Often plenty of bars, but no data.

But in NZ any VFR level and virtually anywhere in the country means good data. Same in the Western US within 10-20 miles of a settlement (all this GSM).

In N Europe usually same as UK, but South of France similar to US.

Presumably all this is related to the local topography. Maybe presence of users at higher elevations means the signal has to have a greater vertical coverage?

[Lone_Ranger]

I made a call at 5000ft a few days ago over Stroud, not something I've done before so no idea if it was a fluke

[Gertrude the Wombat]

worst case is the annoying electronic noise on the intercom
I've read reports here of it also causing the VOR needle to point the wrong way.

But of course as you're using the phone to navigate in IMC you don't need the VOR so why would you care? :D:):ok:

[Gertrude the Wombat]

With GSM there is a problem in that the protocol assumes the signal takes less than a certain time to go between mast and phone. If the signal takes too long it does not work. I seem to remember the maximum distance is ~15NM.
My recollection is 35km (I've got a large pile of the ETSI/3GPP standards on my desk, the details are in there somewhere, but I'm afraid I'm not going to go looking right now).

If the phone is a long way from the mast it has to transmit its signal early so that the mast receives signals from all phones properly slotted together, and there's a limited number of bits in the protocol for telling the phone how early to send its signal. Plus, before you get that far, there's a limit to the amount of slack in the timing for the initial contact from the phone (before it's been told how early to transmit).

[andrewc]

The GPS mode of your phone is simply receiving signals from the
GPS satellite network to work out your position. It doesn't involve
any phone transmission,

-- Andrew

[CruiseAttitude]

Unlike the iPad where the inbuilt GPS works in 'Airplane Mode', the iPhone GPS does not. I've read that this is because GPS and GSM/LTE use the same chip in the iPhone.

[Whopity]

My understanding is that it's not illegalI think you will find that the Mobile Telephone Company's Ofcom Licence to operate prohibits aeronautical operation in which case you would be in breach of the licensing conditions! This was true of early Cellphone Operator Licences; I am not sure if it still is.

Cellphone antennae are designed with a very low angle of radiation to reduce power and minimise their use at altitude, where in theory they are not needed.

[flybymike]

Simply remove the SIM card from the phone and the irritating chatter and any potential avionics GSM interference will disappear. The GPS will still work and the battery will last a bloody sight longer while not constantly searching for mast signals.

[thing]

Simply remove the SIM card from the phone and the irritating chatter and any potential avionics GSM interference will disappear. The GPS will still work and the battery will last a bloody sight longer while not constantly searching for mast signals.

Good call, will try that.

[Howard Long]

I think you will find that the Mobile Telephone Company's Ofcom Licence to operate prohibits aeronautical operation in which case you would be in breach of the licensing conditions! This was true of early Cellphone Operator Licences; I am not sure if it still is.

Cellphone antennae are designed with a very low angle of radiation to reduce power and minimise their use at altitude, where in theory they are not needed


So then the various commercial airborne picocell solutions are illegal?


Handset antennas are, these days, designed to be as compact as possible largely at the expense of radiation pattern, their performance artificially enhanced by transmitting more power, both at the handset and at the tower. The old pointy out antennas went out of fashion ten years ago for aesthetic reasons only, definitely not performance.


The problem of cellphone disruption in the air is largely due to (a) interference to the handset from multiple cells on the same frequencies by dint of height and (b) interference from the handset to multiple cells. The cells are, after all, designed with the assumption of terrestrial coverage in mind.


That's why when you used to go up 1 Canada Square in Canary Wharf beyond about the 20th floor, your cellphone wouldn't work. Only when they put in picocells on each floor could you make and receive calls. As the cells were now very small, the phones themselves put out much less power, perhaps 1000 times less, and so therefore don't disrupt the main terrestrial cell infrastructure.

[gaxor]

I think you will find aircraft installed picocells backhaul the signal via satellite. They do not directly interact with the cell infrastructure.

Gary

[Howard Long]

I am not sure who that is aimed at, but I don't think anyone suggested that the airborne picocells were piggy backing off the terrestrial cell structure.

Just sayin'!

[BigEndBob]

On landing at Brum on commercial flight from the US, i was suprised my phone was connected to the Irish telecom network?