Any PROOF of Mobile Phone "interference"?
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Bip-dibber-dib-dibber-dip
How about an A320 during SRS phase of take-off dropping into heading+v/s, coincident with the bip-dibber-dib-dibber-dip noise? Traced to the management bod sitting on the J/S! 
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As an RF and EMC engineer I can tell you that there is a definitive answer to the question:
Yes but.......
The interference depends on three critical factors, the RF power used, the frequency band used and the type of modulation. All these three vary in different countries.
Cellphones can be 450MHz, 800MHz, 900MHz, 1800MHz etc... Interference is VERY frequency selective and the airborne systems MAY only be susceptible to one of those bands.
Cellphones can also use different modulation, on-off pulse types like GSM, wideband like spreadspectrum or fixed carrier. Interference will be more noticeable from on-off pulsed types like GSM.
Given also that the RF power used is controlled by the system and can vary from almost nothing to 'beyond the certified limit' of the airborne systems you have a huge range of possible scenarios. Most people will quite rightly be able to say that 'their phone never caused a problem'.
I have instruments mis-read, computer systems crash, volatile memories scrambled, other radio receivers go 'deaf' etc....
Then add the 'invisible' effects. Such as the RF causes the computer system to crash but the computer uses as watchdog program that re-boots the system after any such crash. No visible sign of interference but the computer has effectively gone awol for a percentage of the time.
So to complete the answer:
Yes BUT only a small percentage will.
How good is your risk management
Yes but.......
The interference depends on three critical factors, the RF power used, the frequency band used and the type of modulation. All these three vary in different countries.
Cellphones can be 450MHz, 800MHz, 900MHz, 1800MHz etc... Interference is VERY frequency selective and the airborne systems MAY only be susceptible to one of those bands.
Cellphones can also use different modulation, on-off pulse types like GSM, wideband like spreadspectrum or fixed carrier. Interference will be more noticeable from on-off pulsed types like GSM.
Given also that the RF power used is controlled by the system and can vary from almost nothing to 'beyond the certified limit' of the airborne systems you have a huge range of possible scenarios. Most people will quite rightly be able to say that 'their phone never caused a problem'.
I have instruments mis-read, computer systems crash, volatile memories scrambled, other radio receivers go 'deaf' etc....
Then add the 'invisible' effects. Such as the RF causes the computer system to crash but the computer uses as watchdog program that re-boots the system after any such crash. No visible sign of interference but the computer has effectively gone awol for a percentage of the time.
So to complete the answer:
Yes BUT only a small percentage will.
How good is your risk management
On an A320, ECAM messagethat a MLA computer had failed. Being a non dispatch item we were keen to fix it. Nothng worked until a suspicion led us to make a PA to ask the pax to make sure their phones were switched off. Problem went away about 15 seconds later.
Avoid imitations
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Yes Ray, mobile phones certainly do affect some aircraft. As well as interfering with the intercom/radios, our aircraft's aft baggage bay smoke warning comes on in flight if a live phone is left in there. As there is no fire extinguisher in the baggage bay (and the fuel tanks sit below it) the emergency checklist says it's a land as soon as possible, which could mean in a field in our case. Especially not funny if IFR. It's specifically emphasised in our pax brief for that reason.
BTW, for more info, there's been at least other three threads on this subject within the last year or so. Search for "mobile phone".
BTW, for more info, there's been at least other three threads on this subject within the last year or so. Search for "mobile phone".
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In A343 Ive seen the the Capts mobile cause random 'flip-flopping' of PFD & ND (on ground before push back)
Have also seen/heard ground engineers radio causing the fancy bullet proof door to unlock when he pressed to transmit!
Have also seen/heard ground engineers radio causing the fancy bullet proof door to unlock when he pressed to transmit!
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My groundschool instructor told me about a friend of his in his new Cirrus that had a switched on mobile in the centre armrest/cubbyhole (like a Ford Mondeo I assume.) Apparently the interference gets stronger the further away you get from the source and the phone caused a problem when it came to disconnect the autopilot.
I think it had caused real damage to the system and a CB or two had to be pulled in order to disengage it. Not exactly first hand as stipulated but I have no reason to doubt its authenticity.
I think it had caused real damage to the system and a CB or two had to be pulled in order to disengage it. Not exactly first hand as stipulated but I have no reason to doubt its authenticity.
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Good chance they kill
A big fellow Pat when I was in Botswana a few years ago had his fisrt solo flight on the S333 (269D) helicopter.
Very good reason to belive his ex or someone called him on his mobile( it was investigated but no evidence-pre paid phone?) during the helicopter being refueled,
the fuel cap was found on but not rotated and locked.
Result result was a short firey fatal flight.( 7 day fight for life)
Something I never want to see again- is a phone call that important leave em off when ur working.
RIP PAT P.
Cant get any more interFEERing than interFEERing with the CAPTIAN
Very good reason to belive his ex or someone called him on his mobile( it was investigated but no evidence-pre paid phone?) during the helicopter being refueled,
the fuel cap was found on but not rotated and locked.
Result result was a short firey fatal flight.( 7 day fight for life)
Something I never want to see again- is a phone call that important leave em off when ur working.
RIP PAT P.
Cant get any more interFEERing than interFEERing with the CAPTIAN
Last edited by ampk; 27th May 2006 at 14:35.
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Mythbusters
None of you watch Mythbusters on Discovery?
There's an episode where they test the cell phone myth on airplanes. Quite an interesting episode I must say.
I'd love to post the results of their findings, but it gets way too technical for me. My suggestion, watch it !
It's episode 12 of season 3, in case you are interested.
Enjoy !!
There's an episode where they test the cell phone myth on airplanes. Quite an interesting episode I must say.
I'd love to post the results of their findings, but it gets way too technical for me. My suggestion, watch it !
It's episode 12 of season 3, in case you are interested.
Enjoy !!
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744 short finals for Singapore, F/O flying, me just gone to PA to secure the cabin for Landing. I hear dialing beeps through the headset, a bit of connecting squirt, and all the RHS nav instruments go AWOL, with the associated whistles, bells, flashers, autopilot dropout etc. That was real enough for me. As`others have said, could depend on the phone itself, the position, and even the surroundings---the nice titanium laptop case or metal briefcase might act as a reflector to intensify or focus the signal.
CAA studies seem to conclude possible problem. I concur, apart from which---make the most of a few hours with the pesky thing off!
CAA studies seem to conclude possible problem. I concur, apart from which---make the most of a few hours with the pesky thing off!
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A pretty convincing case for me.
Captains Navigation Display suddenly started oscillating as if the aircraft were rapidly turning left 30deg then right 30deg. PA made to passengers resulted in one passenger discovering that this phone had been accidently left on. After switching phone off - problem immeadiately disappeard.
Same symptoms on other flights - same PA made - same immeadiate miraculous fix experienced - though on these occassions no pax actually confessed. I am pretty convinced though.
HP
Captains Navigation Display suddenly started oscillating as if the aircraft were rapidly turning left 30deg then right 30deg. PA made to passengers resulted in one passenger discovering that this phone had been accidently left on. After switching phone off - problem immeadiately disappeard.
Same symptoms on other flights - same PA made - same immeadiate miraculous fix experienced - though on these occassions no pax actually confessed. I am pretty convinced though.
HP
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Actually Ray Darr, your post regarding the background of how the mobile phone ban came about is not correct. FAA does not specifically ban the use of mobile phones, FCC does, nor did they approach FAA and request a ban on such. In fact, FCC is now ready to remove the restriction. FAA has always maintained that no electronic device can be used onboard until it has been determined that it will not cause adverse side effects, (interference). This determination is left up to the aircraft operator(s), hence the different policies regarding when and if devices can be used by the various air carriers.There is quite a bit of anecdotal evidence pointing strongly to mobile phones AND other portable electronic devices causing interference, studies are ongoing. You might find this of interest.
http://www.avionicsmagazine.com/cgi/...06&file=qa.htm
http://www.avionicsmagazine.com/cgi/...06&file=qa.htm
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If it's not broken, don't fix it!
Wonder how long it is going to take before "they" can quantify these little headaches. Luckily for me, the planes I fly are so old that the interference is to the phone and not the aircraft. Good luck to you chaps in your TV-guided missiles!
Cheers!
Mind the tail!
Cheers!
Mind the tail!
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Originally Posted by rabidpangolin
Luckily for me, the planes I fly are so old that the interference is to the phone and not the aircraft.
Does your plane not use any Nav aids?
I've heard of VOR's going nuts due to mobile phones.
