Mobile/Cellular Device Interference

[jesty]

Does this actually occur? So far, from what I can gather, all that exists is circumstancial/andecdotal evidence of mobile phones and other wireless portable electronic devices causing interference with aircraft systems. No official research has been conducted into the issue, but everyone from the FAA on down has adopted a sort of "could potentially be dangerous, let's ban it outright" stance.

Can anyone shed some light on this - does it happen? which systems in particular are affected by mobile phones or other devices? I was once asked to turn off an mp3 player on a Braathens flight, Norway domestic. I didn't want to make a fuss, so I complied, but it has no radio transmission/reception functionality. In retrospect, it does contain a hard drive that spins at 5,400 rpm, which might generate some EM noise, but if one of those could affect cockpit instrumentation 15m away, why would the same hard drives be fine in normal home computers and laptops, within the confines of the computer chassis?

I'm confused by this entire issue so if anyone knows more, please let me know.

[krisgnair]

Re: Mobile/Cellular Device Interference

Hi

When you switch on the mobile during the flight your mobile instrument try to locate the nearest base station and it will radiate more energy compared, when you are on the ground. Whenever your mobile is out of coverage area it radiates more energy to gain access to the nearest tower. Research showed that this radiation or interference from the mobiles affects the avionics particularly during take offs and landings and its been proved that because of this interference the aircraft have been deviated from the ILS system.

The future system consists of a Pico Cell installed onboard the aircraft which collects all the signals and process it with the help of onboard servers and send it back to the earth station through satellites.

If you are more intrested visit http://www.onair.aero/en/index_en.asp

[BOAC]

Re: Mobile/Cellular Device Interference

This subject has had a lot of coverage on PPRune and I think you will find it inTech Log so I'll pop it in there for you.

[ionagh]

Re: Mobile/Cellular Device Interference

Originally Posted by jesty

but it has no radio transmission/reception functionality.

You have to consider two seperate scenarios:

i) Very low level EM radiation from ANY electronic circuits (especially digital).

ii) High level EM radiation from an intended transmitter (mobile/cellphone etc)


(ii) Can and does have an effect on other electronic circuits (not just radio receivers). Can cause data corruption, glitches, instrument errors etc. How likely this is depends on how close the transmitter is to the 'victim' equipment and how 'immune' the victim is to such EM radiation.

(ii) Can also cause some receiving equipment to saturate, malfunction or be blocked even if it is not operating on the the frequency band.

(i) The EM interference generated by the equipment may just happen to fall on a frequency used by an avionics receiver on board. This causes loss of sensitivity, intereference etc and may be transient or constant.

Every case is dependant on many parameters and the overall situation can be likened to a risk-management approach.
How much risk do you consider acceptable?

[notdavegorman]

possible example of mobile phone interference

Forgot to switch off my mobile, on 6nm final at AGP, heard my text message tone, telling me my 'welcome to Spain' message from Vodafone ES had arrived. Simultaneously got a predictive windshear fail annunciation. Might just have been a coincidence, or might not have been.

[Sky Wave]

Re: Mobile/Cellular Device Interference

but everyone from the FAA on down has adopted a sort of "could potentially be dangerous, let's ban it outright" stance.

Better than the "I guess it should be ok, let's wait and see if we get any accidents" stance

[jesty]

Re: Mobile/Cellular Device Interference

Originally Posted by Sky Wave

Better than the "I guess it should be ok, let's wait and see if we get any accidents" stance

But still less preferable to "let's commission some research into the subject and get a definitive answer, but we'll be cautious in the meantime."

[FlyVMO]

Re: Mobile/Cellular Device Interference

I believe some avionics engineers at ERAU in Florida did some research into this a few years back. I'll see if I can locate anything about it and post a link here if I do.

Didn't find quite what I was looking for, but here is a page with some interesting reading-including a couple of very telling in-flight occurences. A professor Helfrick at ERAU is named, so I guess thats what I was remembering.

http://www.airnig.co.uk/emi.htm

I'll have another look when I have more time.