[PilotTom]

I have been reading the Pooley's Air Pilot's Manual: Air Law & Meteorology book. P.173 states that;

In addition, the use of a mobile telephone on board an aircraft can interfere seriously with its navigation equipment. Even in stand-by mode, mobile phones emit signals periodically. Not only is there an adverse effect on safety, but the use of mobile telephones in an aircraft is a breach of the telephones users' licence. Therefore the commander of an aircraft should ensure that all mobile telephones are switched off prior to engine start.

From this I have a few questions:
1) If the above is true, how does one legally use live mapping software on their mobile device? Many pilots use SD/Runway HD/etc. on their phones, but if the aforementioned is true they shouldn't be.
2) The same book states that a delay in arrival of more than 45 minutes at your destination should be notified by radio, unless unavailable, in which case through mobile phone.
3) The telephones users' licence? Any reference to it?
4) This seems to be a rule allocated solely to GA. Commercial flights allow the use of mobile phones during the flight, at the discretion of the operator. Why the difference here?
5) The book references Part NCO. GEN.125 as the source of these statements. Having read the reference material there is very little coverage of Mobile Telephones and where it is covered it simply states:

A well-known interference is the demodulation of the transmitted signal from GSM (global system for mobile communications) mobile phones leading to audio disturbances in other systems. Similar interferences are difficult to predict during the PED design and protecting the aircraft’s electronic systems against the full range of potential interferences is practically impossible. Therefore, not operating PEDs on-board aircraft is the safest option, especially as effects may not be identified immediately but under the most inconvenient circumstances.

This is a statement, which in my interpretation, gives advice, not instruction.

Any clarification is greatly received.
Tom

[Kemble Pitts]

Tom

There are two legislative angles to this topic; the aviation regulations and the Ofcom bit.

In the UK Ofcom sells licences to organisations to use various radio frequencies for a range of uses with certain limitations. There is a large tome specifying what frequencies can be used where and for what and by whom - all the way from HF up to microwave frequencies.

Those frequencies allocated for mobile phones are restricted to terrestrial use only.

The big mobile phone companies pay huge licence fees, to Ofcom, for chunks of those frequency bands. They then sell you and me a contract to use those frequencies on our phones. We have to observe the 'terrestrial only' limitations as only Ofcom can vary those and would only do so if the licence holder (EE, Vodaphone, blah) requested it. This they are unlikley to do as there is no good reason for them to make such a request.

Then there is the aeronautical regulations bit.
A feature of mobile phones is that they frequency hop and vary their transmit power in conjunction with the ground station (the mast). So, when you use one you not only can't control the frequency or the power but you have no idea what they are either.

This causes difficulties if trying to carry out a conventional EMC test on an aircraft, and there are important aircraft systems that operate on or around some of those frequencies (or harminics) and this concerns EASA. So EASA says you can't use mobile phones in aircraft unless you prove it is safe.

To cater for this they have 'invented' things called T-PEDs - Transmitting Portable Electronic Devices. Essentially mobile phones and the like. You need to prove that your aircraft is 'hard' against T-PED emissions.
EASA considers this a Major modification and there are recognised ways of carrying out the necessary EMC testing using transmitters that mimic mobile phone transmissions but which can be controlled in terms of frequency and transmit power.

Of course, assuming you get your aircraft T-PED approved, that only proves and certifies that the aircraft is safe for the use of mobile phones - it doesn't sort the Ofcom problem.

I believe the airlines resolve that issue by installing a small, low powered, cell (or 'phone mast' if you like) in the aircraft that passengers' phones can connect with and this then goes out via a satcom link.

They might also have built a dedicated 'airborne network' along some of their airway routes but I'm only hazy on that system.

Hiope that helps.

[Kemble Pitts]

... oh yes, and there are some contradictory messages coming out of the different EASA departments on this topic.

[malcolmfrost]

1) If the above is true, how does one legally use live mapping software on their mobile device? Many pilots use SD/Runway HD/etc. on their phones, but if the aforementioned is true they shouldn't be.

SD maps are downloaded before use and aren't streamed. The GPS on phones doesn't rely on a mobile signal.

[PilotTom]

Kemble Pitts,

Thank you for your detailed description, very much appreciated. It’s a shame the book couldn’t convey the information in an equally informative way. I’m sure this will help others too.

Given your description, am I right in saying that the use of a Mobile Phone is not prohibited, simply the use of a Mobile Phone capable of transmitting on a mobile frequency? Thus, a mobile phone in flight mode used by a passenger for photography, for example, would be permissible.

Malcolm Frost,
With regards to the maps, I agree. I was led to believe that some of these tools were capable of obtaining a live weather, aerodrome info and NOTAM feed if a suitable connection was available. I made the assumption that this included during flight. Having read some more it looks like I was incorrect with this assumption.

———————
My first post on this forum whilst I train to convert my NPPL (M) to a PPL (A) at Gloucester. Very impressed with the quality of response, thank you both.

[flybymike]

Rightly or wrongly, folk are certainly using SIM cards in tablets and phones to download notams and weather etc in flight.

[Kemble Pitts]

[quote="PilotTom"]Kemble Pitts,


Given your description, am I right in saying that the use of a Mobile Phone is not prohibited, simply the use of a Mobile Phone capable of transmitting on a mobile frequency? Thus, a mobile phone in flight mode used by a passenger for photography, for example, would be permissible.


As its the radio frequency transmissions that can cause the problem then it should be fine in 'airplane mode' [sic].

Good luck with the licence conversion.

[cockney steve]

You may also be aware that mobile phone use is prohibited in petrol filling stations because they "could" cause a spark and ignite the fuel- vapours.
As far as is known, worldwide, there has never been a PFS explosion or fire. more hazardous is synthetic clothing/carpets/upholstery.....have you ever had a "belt" off a car-door handle?

IMO the mobile phone guff is pure backside- covering. certified aircraft equipment should be properly shielded and designed to bond properly. Since mobiles went mass-market, huge sums have been thrown at development.Avionics, by comparison, is a cottage-industry.

[rikur_]

IMO the mobile phone guff is pure backside- covering......

There's an element of this.
I was involved at the periphery of testing in the mid-1990s - and the problem was it was difficult to conclusively prove that it couldn't cause a problem, even though there was little evidence of it causing a problem. There were various anecdotal reports from a relatively small number of flights about unexplained avionics behaviour that was resolved by getting a passenger to switch off portable electronic equipment.

Another issue is that it can cause problems for cellular networks. The design of cellular networks is based on the basis of careful reuse of the same frequencies at multiple cell sites, relying on attenuation, directional antennas and natural screening to prevent interference between sites. A phone in the air may potentially interfere with multiple sites on the same frequency.

As its the radio frequency transmissions that can cause the problem then it should be fine in 'airplane mode'

Worth noting that some of the equipment reported to have caused problems in the mid-1990s wasn't intentionally transmitting - as laptops back then didn't have wifi, bluetooth, etc.
BA policy at the time was that all personal electronic equipment to be switched off during take-off and landing as a result.

If I have understood correctly, for use in a GA aircraft then it's only the mobile phone element that needs to be disabled, WiFi and bluetooth is legal .... albeit few phones make it easy to disable just the phone aspects (removing the SIM card doesn't do this)

[malcolmfrost]

Malcolm Frost,
With regards to the maps, I agree. I was led to believe that some of these tools were capable of obtaining a live weather, aerodrome info and NOTAM feed if a suitable connection was available. I made the assumption that this included during flight. Having read some more it looks like I was incorrect with this assumption.

———————
My first post on this forum whilst I train to convert my NPPL (M) to a PPL (A) at Gloucester. Very impressed with the quality of response, thank you both.

I have to confess I am less than rigorous in turning off the mobile part of my iPad and phone so I do get the occasional update of weathers, but it does seem that the mobile signal is very highly directional, so it basically hugs the ground.

[johnm]

@PilotTom We're based at Gloucester with Cotswold Aero Club, who are you training with....

[kanga]

..
———————
My first post on this forum whilst I train to convert my NPPL (M) to a PPL (A) at Gloucester. ...

I early days of mobile 'phone usage (before I had one, a cast-off from one of my children ), I could hear while still on the ground on our shareoplane's ancient (King, IIRC) VHF radio if a passenger's 'phone was on as it pinged the nearest cell tower. Never heard that with later cell 'phones nor with later (flip-flop) VHF transceivers. But perhaps passengers were always both listening and obedient when I told them to switch their 'phones/tablets off or to 'flight mode'. But in an airborne emergency with total radio failure I'd probably switch my 'phone 'on' to telephone nearest ATSU, risking the later wrath of OfCom. I had got into the habit of carrying it when flying, preloaded with SD flight plan but switched off.

Anyway:

a. welcome to Forums
b. hope you've visited Jet Age
c. visitors always welcome at Gloster Strut, monthly meetings on 2nd Tuesdays. Tonight's meeting (Victory Club, Lypiatt Road, Cheltenham, 1930) is by a married couple of Strut members on racing light aircraft in Africa and flying them around Western Australia.

[PilotTom]

@PilotTom We're based at Gloucester with Cotswold Aero Club, who are you training with....

I am training with Staverton Flying School, based over at their new SkyPark hangars. It’s a tough call picking someone at EGBJ, so many options with different aircraft, availability and prices.

[johnm]

Thanks @PilotTom , look out for TB20 GCORB

[KN58]

..
———————
My first post on this forum whilst I train to convert my NPPL (M) to a PPL (A) at Gloucester. ...

I early days of mobile 'phone usage (before I had one, a cast-off from one of my children ), I could hear while still on the ground on our shareoplane's ancient (King, IIRC) VHF radio if a passenger's 'phone was on as it pinged the nearest cell tower. Never heard that with later cell 'phones nor with later (flip-flop) VHF transceivers. But perhaps passengers were always both listening and obedient when I told them to switch their 'phones/tablets off or to 'flight mode'. But in an airborne emergency with total radio failure I'd probably switch my 'phone 'on' to telephone nearest ATSU, risking the later wrath of OfCom. I had got into the habit of carrying it when flying, preloaded with SD flight plan but switched off.

This limitation was in place for the mobile phone networks before GSM came through. Those "analogue" mobile systems (1G) were not secure for obvious reasons and had the potential of interfering with the avionics for the aircrafts and the Radio stations.
GSM / HSDPA and now the LTE are fully digital systems and are encrypted. There are guard bands in place in the frequency spectrum specifically to avoid interference.