Mythbusters - Mobiles & Planes

[Deejay 1]

Just a reminder (and this is not an ad!)

Tonight Monday 02 Oct Mythbusters explore what happens if mobiles are used in planes. SBS 1930.
I reckon that this is bound to generate some discussion!

Rock on!

Deejay 1

[clear to land]

Must say I thought it was overexaggerated bs (the mobile thing, not the show as I haven't seen it.) Been flying modern jets for a few years now, and haven't had any probs. Then about a month ago, just after T/O with A/P engaged (middle of the night local) we heard the 'normal' mobile associated radio interference. Just said to offsider 'some idiots phone is on' when A/P disengaged for no other obvious reason. Handflew for a bit then re engaged OK, turned out to be colleagues mobile (surprised I actually remembered to turn mine off!). But now I am a believer!:ugh:

[Aussie]

Im going to miss it, anyone care to post the results?

Cheers


Aussie

[Aerodynamisist]

I have seen the ident interrogation light on the transponder flicker in concert with the ticker tick tick that you get in your headphones when a phone rings. never seen the vor deviate though.

[Ultralights]

Just finished watching it, Myth Busted. though i tend to dissagree, they tested all types of Mobile phones in a farahday cage, only phones transmitting in the 800 to 1.5Mhz range had a significant effect to the VOR receiver, cause a huge needle deflection and occasionally the TO/FROM flag to flip between the two.

the same test rig was put on board a Business jet, which remained grounded due to FAA regs banning mobile phones in flight, but all phones on board the Jet had no effect on any instrumentation...


I have personally left my phone on in my Nav bag in the back of a PA28, and the associated Bzzzing noise with the phone recieving a messgage has caused the VOR to flick, as well as scaring the hell out of me with the excessive noise in ym headset.

If the Autopilot was coupled to the VOR i could see how it would create some seriously interesting control movements

[maxgrad]

The nature of my job auth. me to have a mobile on, (can only use it if req above a050).
The show was enjoyable but personally I have never seen that type of interference due a mobile ph.
Makes you wonder though

[18-Wheeler]

So everyone is totally happy that the insulation on the wiring on their 20 year-old+ aeroplane is 100% perfect?

Yes?

[CVTDog]

My phone has a flight mode option - what is that supposed to do ? I am told turn tun of my pone even if that is fitted ?

[Ultralights]

from what i have read, the Flight mode in some mobiles disables the identifying transmission, the mobile will transmit an identifier so the recieving tower knows where the phone is and knows which tower to direct calls to be transmited to the phone, in aircraft mode, this is disabled.

next time you go for a drive in the city, leave the mobile on somewhere near your car radio, as you drive along you will hear the familiar mobile interference from the mobile as you move through different tower ranges yet you will not recieve a call or SMS.

[J430]

Gents,

Just for the record, the Hawker XP they used may in fact have not shown any nav instrument issues in that test, however nobody checked Transponder outputs. I note one poster here did comment their transponder light flickering.

WellI have posted before on this topic and I hereby present more FACTS!!!!!

GSM phones do interfere with your transponder. I have equipment that is only 2 years old, not 20+, and I assure you after much proving the myth, that your transponder is affected by a GSM phone, some cases making SSR signals totally unreliable.

I have found a few times when Brisbane Radar have had an ident issue that a GSM mobile has been on in the a/c, even after my requests. As soon as all phones are confirmed off........."Identified".

If this is not enough, I have spoken to the manufacturers who have confirmed in their own tests that the Transponder is affected by the idle GSM phones, they found this themselves in a lab, I have found it in the air.......enough proof.....DONT DO IT.

Tell anybody you think of, its true, its not 100% of the time, but when it is time its 100% effective.

I have not seen a GPS error in my plane, however I have seen a handheld do a few funny things once with a phone in the cockpit, and there are some very serious concerns about a few mysterious CFIT's in this country that can not be easily traced to a phone, but given my experiences, they well could be to blame.

If in doubt.........DON'T

Rant over!

J:ok:

[Ultralights]

i wonder if firing off an email to Mythbusters requesting they conduct more tests on different systems? the episode only tested the VOR and Comms transmissions.

maybe they will return to the Myth and confirm it does actually interfere with vital equipment and its transmissions

[esreverlluf]

Have left my phone on a lot ex Sydney - never had a problem apart from the odd heavy landing - but then again it's a 767 - I need an excuse. Obviously it's the mobile phone!:ugh:

[virgindriver]

Hey Maxgrad, how well does your mobile work in the air? Mine never seems to have any signal after a few thousand feet..

I have heard from friends on the jumbo that mobiles used to affect the pressurisation outflow valves down the back. I think they might have been radio controlled, not sure.

[maxgrad]

virgindriver,
Depending on location,(relative to towers), I can get a fairly good signal (FL200ish) but will lose signal strength rather fast as I move away from the tower.
I have never seen any effect on the outflow valves that I could attribute to a mobile signal but again I say that it does make you wonder.

The transponder situation is a good example, I will be taking a very close look at that the next time the damn ph springs to life.

[Deaf]

The whole issue of ElectroMagnetic Compatability (EMC) is a nightmare especially for aircraft. Tests just of the installed equipment are non trivial and the complication of a moderately powerfull transmitter at a random localation essentially makes any conclusion suspect. It is well beyond the showmanship of mythbusters to come up with a valid result.

One thing with the GSM phones is the variable transmission power if there is a weak or no base station signal (like on a a/c) it will say HELLO as loud as it can (about 3W), if there is a decent signal (like on an a/c with an onboard base station) it will say hello quietly (a few mW).

[bushy]

You also need to think about what would happen if you had 100 phones (or more) on board.
For information I was told that Qld RFDS took a Telstra technician flying in their Kingair while it was flying ILS's etc to test for interference., There was no problem, but I think that was with the analogue phones. Someone should do the same tests with CDMA phones, as these are very useful in the outback.(has anyone done these tests?) You can often get phone calls, when out of vhf range, And phones are also a good radio backup, in case of failure. Most bush pilots have the tower phone number programmed into their mobile phone.

But, to have 150 phones operating in an airliner that has electronic flight controls.???? That's scary.

[ccy sam]

What about the fly by wire aircraft, not just nav issue but control problems? Not mentioned at all on the program.
Personal experience. On finals in a modern turboprop a few years ago, AP tracking ILS, at about 500' a phone starts ringing back in the cabin overhead bin[ this is before S11, we flew with the cockpit doors open sometimes] AP makes a hard right turn at which point we disengeged it.
Does happen, is a problem!

[itsbrokenagain]

There was a article in I think Business Aviation here in the USA a coupla months ago about this, only reports in it about interference were related to Airbus giving erroneous nosegear indications from memory, will look to see if I still have the magazine here.

[Chadzat]

Someone should do the same tests with CDMA phones, as these are very useful in the outback.(has anyone done these tests?)

CDMA can be a godsend sometimes out of VHF range.- its amazing the amount of places you can get signal. I have used it to notify the destination of our ETA when we have been wayyy out of VHF range. This was particularly handy when the permit for the Aboriginal camp expired the day before! :hmm:

j430, I think I have inadvertantly backed up your theory with the Mode C SSR, the other day I was on a joyflight with pax- approach came back with "intermittent SSR signal- please re-cycle" even when the light on transponder was functioning normally and we were close to the base tower. Turned around to find a bloke on his video phone making a call! :ugh:

[J430]

:D

Thanks CHADZAT

now its proven beyond all doubt!

Yeah and I bet when he turned it off, your signal was good all of a sudden. The Transponder looks good to you, but not so good to ATC.

I have proven this several times, it is no myth at all. Manufacturers confirmed it too!

Cheers
J

PS.....no matter whether phones are on or off I still have trouble keeping straight and level and on track..........maybe I dont have an autopilot:eek:

[Wheeler]

Never mind mobiles, try placing a handheld GPS (not even a transmitter) near the aerial of a VHF navcom.

[Deaf]

"handheld GPS (not even a transmitter)"

Any receiver more advanced than a crystal set is a transmitter - low power but still a transmitter.

[VH-XXX]

J430 - you wouldn't have any more problems if you ditched that damn Microair transponder. That kinda stuff doesn't happen on real transponders like King, Collins and Garmin. Get with the program!

Oh and when they said "recycle," they didn't mean toss out the window.

[Deejay 1]

I knew that this would generate a fair amount of comment.

I too watched the show and thought it somewhat inconclusive.

Interesting in that they did mention "hand held" devices but failed to try these out.

Does anyone recall the Lauda Air 777(?) that sadly went down over Thailand a few years ago (engine 2 went into reverse thrust or something) the story being that this was caused by excessive power/rf from a notebook computer?

If there is any truth in this it makes you wonder what else can affect instruments.

Rock on!

Deejay 1

[Aussie Andy]

I have mixed feelings on this:

When flying VFR in PA28s etc I have sometimes inadvertently left one on and have heard a bit of a buzz in the headsets, and had some VOR interference (will depend on the a/c cabling condition and layout more than anything I would guess). I would expect that a portable GPS would be likely to be affected too -- very sensitive receiver meets loud pulse-modulated RF noise generator in close proximity! Possibly less risk if good sheilded coax with loss-less / leak-less joints connect the GPS to an external antenna. Anyway, I am much more careful about the issue when flying in IMC is a possibility and have "PHONES OFF" on my pre-flight checklist...

When flying BA across the pond to the US (about once every month or two as part of the day job) I usually remember to turn off my GSM/GPRS Blackberry and mobile phones... but twice in the last year or so, I am sorry to say, I have landed at SFO or ORD and then realised that I have left the phone or Crackberry on in my jacket which the nice BA ladies had hung in some store cupboard during the flight (747 or 777), with no apparent ill effects..!

I see that US adverts for cell-phone / headset adapters (e.g. here: http://www.mypilotstore.com/MyPilotStore/sep/1767) provide the following caveat: Note: The FCC does not allow the use of a cell phone in an airplane while in flight. Current regulations allow cell phone use in the cockpit while the plane is on the ground.

Andy :ok:

[AirSic]

Watching channel 7 news tonight, Alanah Mc Tiernan, the minister for Dept of Planning and Infrastructure (WA), was in the front seat, of the local chopper, and in front of her, mounted on the instrument panel was a mobile phone, and it was "flipped-open", Charging??? and on??


They would have been in CTA for sure as they departed from the city helipad for the new estate of Alkimos, Northern Suburbs of Perth.

What the?!?!?!?!:= :sad:

[Aussie Andy]

VFR - shouldn't be a problem!!! :ok:

[Reverseflowkeroburna]

I have had the GPS lose the plot/signal and queried the pax on their mobile phone status. Once Mr. Forgetful turned his off, the unit (TSO'd Bendix/King KLN90B installation from memory) regained its composure!! Coincidence??? Maybe.

[maui]

Deejay 1. That was a 767 not 777. To date all 777's still in one piece.

[an3_bolt]

Boeing Aero magazine had a study on electronic interference - 2nd quarter 2000.

I have not sought permission to reprint - but link:
http://www.boeing.com/commercial/aeromagazine/aero_10/interfere_story.html

[J430]

VH-XXX

Mate, if you read some other stories here the other manufacturers products have had a similar problem at times. The local avionics old guy confirmed it too.

Now I have not been asked to Recycle like the guy in SA was, but I guess in an old 60's vintage a/c the term could be quite appropriate:}

J:ok:

[Capt Wally]

....................with my work there are mobile phones onboard on every flight, (mainly CDMA these days) they have been tested (both types) for any problems, none recorded so we aviate LRN via GPS all over the countryside like the Leyland Bros & where still here, or there depending on how ya look at it !:-).....although like they always say.....if in douibt don't !:-)

Capt Wally :-)

p.s............I was once told back in the early days of Mob Ph's (b4 someone thought hey maybe they interfere with navigation etc.) that we where asked not to use them onbaord a flight purely 'cause the Ph Co's couldn't track easily the phones jumping from one tower to another (due to the mode of transport albiet an A/C) mainly for billing purposes:-)...just another added furphy no doubt:-)

[clear to land]

ccy sam, my recent experience of the A/P disco was in 777 (FBW). To paraphrase an old saying, "It won't happen everyday, but it WILL happen". (Although it never seemed to be a problem in the NG).

[15MileRock]

I regularly have my CDMA phone on in the air, same goes for some pax, I suspect, and have never experienced an issue with it - with frequent sending and receiving of messages and the odd call - no just on standby.

Not proof positive, but has anybody had issues?

[archangel7]

Does a Mobile phone work at FL400?

I dont think so...

I find it hard getting reception bellow A050...

[Lasiorhinus]

:eek: I get the best reception below 5000 feet.... :}

Seriously, with a GSM phone, it will work fine under about 3000 or 4000 feet AGL, but go higher than that, and the phone doesnt work anymore. It will, however, display full strength signal indications.

The problem is, that the phone is in range of too many towers. GSM works with only a couple of towers at a time, and when you get too high, the Network starts to refuse the Phone ... not the phone stopping working.

CDMA phones on the other hand, love more towers. The more the better, so they work fine at altitude. Ive successfully used CDMA at 10,000, but thats only because I dont carry oxygen. :eek:
Anecdotal reports have them working fine at FL250.

[Dick N. Cider]

For what it's worth I have had occasion to chase pilots on their mobiles in flight more than once. On one occasion an aircraft transitting YARM CTAF had a dodgy transponder putting out mode C F260 (hmmmm, maybe it was the phone!) causing havoc with overflyers. Looked the aircraft up in the register, got an owners name and address. Looked up a phone number in white pages on line (which had a mobile listed) and rang the lad. He was ridge running but took the call, went mode A and all was well.

More recently had an aircraft with alternator failure (Tx/Rx switched off). We were busily turning on aerdrome lights in Broome and Derby in case he needed them. Talking to AUSSAR letting them know he'd popped up briefly to report ops (semi) normal and revised estimate. AUSSAR, "Oh, we know that." My immediate response, "How the $#@& do you know?" "His mate is SMSing him and phoning us with updates." Eventually got the number and spoke to the pilot directly. They come in handy...