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Glom
Topic Author
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Effects Of Mobiles On Planes

Mon Apr 26, 2010 7:39 am

I'm on for doing a safety moment about phones on planes. I was inspired to do it I had phones causing really annoying disruption to my comms the last time I was flying.

How common is the dit-dit-dit-dit-dit-dit-dit in the ear of the pilot? I've heard talk of localiser needles being offset and fuel totalisers going screwy. There was even a mention of a thrust reverser being triggered.
 
tdscanuck
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RE: Effects Of Mobiles On Planes

Mon Apr 26, 2010 5:11 pm

Quoting Glom (Thread starter):
How common is the dit-dit-dit-dit-dit-dit-dit in the ear of the pilot?

Very.

Quoting Glom (Thread starter):
I've heard talk of localiser needles being offset and fuel totalisers going screwy.

Both of those systems are phenomenally sensitive, so those are some of the most likely effects to see if you get any impact on the avionics.

Quoting Glom (Thread starter):
There was even a mention of a thrust reverser being triggered.

That I've never heard of...for a bunch of reasons, that should be impossible.

Tom.
 
YWG
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RE: Effects Of Mobiles On Planes

Tue Apr 27, 2010 2:58 am

Quoting Glom (Thread starter):
How common is the dit-dit-dit-dit-dit-dit-dit in the ear of the pilot?

It happens to me every now and then. It's not only annoying but just goes to show that someone has decided to ignore the safety warning. It seems the more sophisticated phones like Blackberry and Iphone cause the problem (or maybe GSM networks vs others??). I've flown with people who have forgot to shut their phone off, and pilots DO shut their phones off because it drains the battery searching for a signal in a matter of hours. They realize they've forgotten because we will here the noise and we'll both double check ourselves. The noise only occurs when a signal is received or sent.

That being said, the doppler radar units at most large airports cause the same noise. You can literally hear your sperm being killed or mutated  

Some people don't even notice because their headset is about as good a set of ear muffs.

Quoting Glom (Thread starter):
I've heard talk of localiser needles being offset and fuel totalisers going screwy.

I've never seen either scenario. At most major airports, the controllers will call-you-out if you're off course on an approach just to double check.

Quoting Glom (Thread starter):
There was even a mention of a thrust reverser being triggered.
Quoting tdscanuck (Reply 1):
Quoting Glom (Thread starter):
There was even a mention of a thrust reverser being triggered.

That I've never heard of...for a bunch of reasons, that should be impossible.

I know the iphone can make your coffee and turn your lights off, but really? If that were the case, there would be a whole lot more Captains and F/o's assaulting the passengers   
Contact Winnipeg center now on 134.4, good day.
 
Fly2HMO
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RE: Effects Of Mobiles On Planes

Tue Apr 27, 2010 3:18 am

Quoting Glom (Thread starter):
There was even a mention of a thrust reverser being triggered.

Yeah, no, I'm calling BS on that one.

Quoting YWG (Reply 2):
(or maybe GSM networks vs others??).

GSM phones are the ones that do that. CDMA can interferes as well but it is much much more rare, in the form of speaker feedback at least.

Quoting YWG (Reply 2):

I've never seen either scenario.

I had a couple of AHRS failures and screwy GPS indications (loss of RAIM) while flying with the G1000 or the GNS430, and oh so coincidentally, on all occasions it happened when I either received a call or text when flying.

Other CFI friends of mine have also witnessed screwy LOCs and VOR indications as well, easily fixed by turnging off the offending phone. One guy I knew had a phone that would ALWAYS screw up the older Bendix/King KLN-94 GPSs we had in all the fleet when making a call, but it was his specific phone only.

It makes sense that GPSs would be most sensitive to cell phone interference since both technologies operate within a relatively close frequency spectra (900mhz to 1.5ghz)

[Edited 2010-04-26 20:19:07]
 
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Starlionblue
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RE: Effects Of Mobiles On Planes

Tue Apr 27, 2010 6:45 am

Quoting YWG (Reply 2):
It seems the more sophisticated phones like Blackberry and Iphone cause the problem (or maybe GSM networks vs others??).

GSM thing, not specific to phone model. The dit-dit-dit sound has been around since the dawn of GSM.

[Edited 2010-04-26 23:46:45]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
411A
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RE: Effects Of Mobiles On Planes

Tue Apr 27, 2010 12:20 pm

I have had passengers in my twin Cessna using mobile phones, no 'needle twitching' nor strange audio noises heard.
Types of avionics installed?
All King gold crown....next to Collins, the best there is.

[Edited 2010-05-01 04:07:49 by srbmod]
 
Pagophilus
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RE: Effects Of Mobiles On Planes

Tue Apr 27, 2010 12:25 pm

It's GSM phones which you will hear interference from. CDMA, as noted by Fly2HMO above, and 3G (UMTS) phones will not notmally produce any audible interference, but that doesn't mean they won't affect instruments.
 
FlyHossD
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RE: Effects Of Mobiles On Planes

Sat May 01, 2010 3:36 am

On occasion and especially in a 737-300, the FMC would display a "Check Fuel Quantity" message.
In all but one case when I checked with the cabin crew,
someone in the first few rows was found to be using a cellphone.

In fact, the very first time I thought to check with the flight attendants, the flight attendant asked me,
"How did you know that?" In other words, moments before, she had made the discovery herself.

The 737NGs seem to be much less susceptible to this interference.
My statements do not represent my former employer or my current employer and are my opinions only.
 
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afterburner
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RE: Effects Of Mobiles On Planes

Sat May 01, 2010 5:55 am

Quoting Fly2HMO (Reply 3):
GSM phones are the ones that do that. CDMA can interferes as well but it is much much more rare, in the form of speaker feedback at least.

I don't think it's the system (GSM vs. CDMA). I think it the frequency that matters.

[Edited 2010-05-01 04:08:08 by srbmod]
 
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HAWK21M
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RE: Effects Of Mobiles On Planes

Sat May 01, 2010 7:23 am

Quoting Glom (Thread starter):
There was even a mention of a thrust reverser being triggered.

Any data to confirm that.I don't think so.
regds
MEL.
I may not win often, but I damn well never lose!!! ;)
 
tdscanuck
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RE: Effects Of Mobiles On Planes

Mon May 03, 2010 1:45 am

Quoting FlyHossD (Reply 7):
On occasion and especially in a 737-300, the FMC would display a "Check Fuel Quantity" message.
Quoting FlyHossD (Reply 7):
The 737NGs seem to be much less susceptible to this interference.

The 737CL FQIS is far (far far far) more sensitive to interference of all kinds. The 737NG FQIS is a completely different architecture and much more stable.

Tom.
 
Fly2HMO
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RE: Effects Of Mobiles On Planes

Mon May 03, 2010 2:45 am

Quoting 411A (Reply 5):
Types of avionics installed?

I've experienced first hand interference with full King and/or Garmin stacks.

Quoting afterburner (Reply 8):
I don't think it's the system (GSM vs. CDMA). I think it the frequency that matters.

Not necessarily. GSM has a different modulation (Basically TDMA) compared to other networks (CDMA/EVDO), and they both usually operate in the same relatively close frequency spectra.

Or put differently, a frequency of xx.xx Ghz may cause more interference when modulated as FM, rather than AM, or vice versa.
 
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Faro
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RE: Effects Of Mobiles On Planes

Tue May 04, 2010 9:14 am

What about other aircraft electronic systems/subsystems affecting avionics? Things like electronic systems controllers, transducers, etc? Are all adequately shielded in case of a "spike" in emissivity (malfunctions, storm penetration, etc)?

Faro
The chalice not my son
 
tdscanuck
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Joined: Wed Jan 11, 2006 7:25 am

RE: Effects Of Mobiles On Planes

Wed May 05, 2010 4:46 am

Quoting faro (Reply 12):
What about other aircraft electronic systems/subsystems affecting avionics? Things like electronic systems controllers, transducers, etc? Are all adequately shielded in case of a "spike" in emissivity (malfunctions, storm penetration, etc)?

In order to meet the FAR's, you have to prove that aircraft systems don't interfere with other aircraft systems. This is the major reason why cell phones are such a pain in the rear...there's such a massive variety of types and power levels of emissions from a cell phone that it's functionally impossible to protect the aircraft against all of them.

The aircraft's own systems, on the other hand, are a known quantity and it's much easier to make them all play nice.

Tom.

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