frenchpilot
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Electronic Interference?

Thu Aug 30, 2007 9:31 am

Hi Guys!

I'm looking for some official studies that can proof that electonic equipments such as cell phones and blackberries (even in flight mode), as well as games boys, PSPs, and CD players can cause interference with the navigation systems.

As well, has there been a major accident or incident caused by electronic equipment?

Thanks so much for the help!
"Sur votre gilet vous trouverez un sifflet pour attirer les poissons..."
 
Analog
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RE: Electronic Interference?

Thu Aug 30, 2007 12:18 pm

I doubt that any aircraft or avionics manufacturers would publish such studies. If these studies were done and showed interference, they would have to get rid of the avionics' vulnerability to the interference (it would be hard to argue that an airline could effectively ban such devices.) This would be difficult and expensive, especially if older devices had to be fixed/replaced.

Not navigation, but: If you have access to an aircraft cockpit (or even just a headset), you can do your own experiments to show that GSM phones, that silly French standard  Wink, interfere with baseband audio equipment (like voice comm systems). I can always tell that my phone is going to ring, as I can hear it in my computer's speakers.
 
futurecaptain
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RE: Electronic Interference?

Thu Aug 30, 2007 12:47 pm

I believe there was an airline pilot who wrote something up about a flight he was on where pax electronic devices were interfering with the cockpit. I will try to find it, perhaps someone else will remember what I am talking about too.
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HAWK21M
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RE: Electronic Interference?

Thu Aug 30, 2007 2:32 pm

Quoting Analog (Reply 1):
I can always tell that my phone is going to ring, as I can hear it in my computer's speakers.

The Television too.

Quoting Analog (Reply 1):
Not navigation, but: If you have access to an aircraft cockpit (or even just a headset), you can do your own experiments

On a commercial flight.Very unlikely.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
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Starlionblue
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RE: Electronic Interference?

Thu Aug 30, 2007 8:51 pm

Quoting Analog (Reply 1):
I doubt that any aircraft or avionics manufacturers would publish such studies.

One would thing, but here it is straight from the horse's mouth: http://www.boeing.com/commercial/aer...ne/aero_10/interfere_textonly.html

Quoting FrenchPilot (Thread starter):
As well, has there been a major accident or incident caused by electronic equipment?

Not because of interference no.


As has been often noted on this board, even a device that normally would not emit signals that could potentially interfere can malfunction. But interference that is so bad as to be dangerous from a commercial handheld device is unlikely in the extreme. What with multiple signal paths and shielding I feel fairly safe.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
tdscanuck
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RE: Electronic Interference?

Thu Aug 30, 2007 8:52 pm

Quoting Analog (Reply 1):
I doubt that any aircraft or avionics manufacturers would publish such studies. If these studies were done and showed interference, they would have to get rid of the avionics' vulnerability to the interference

FAA sponsored a study at Carnegie Mellon University that showed that they do affect operation of the aircraft.

Personal electronics don't interfere with the avionics themselves. The systems are much tougher than that. However, personal electronics can radiate EM at frequencies and intensities that affect some of the external signals that the avionics use to do their job (GPS, ILS, VOR, etc.). You end up in a garbage-in-garbage-out situation. The boxes on the airplane have no way to discriminate between the true signal and the interference.

Tom.
 
David L
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RE: Electronic Interference?

Thu Aug 30, 2007 8:53 pm

Quoting Futurecaptain (Reply 2):
I believe there was an airline pilot who wrote something up about a flight he was on where pax electronic devices were interfering with the cockpit. I will try to find it, perhaps someone else will remember what I am talking about too.

This one?
RE: For God's Sake, Switch Off Your Damn Cell Phones.. (by Pilotaydin Jan 12 2007 in Civil Aviation)
 
futurecaptain
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RE: Electronic Interference?

Fri Aug 31, 2007 2:43 am

Quoting David L (Reply 6):

Yes, that's what I remember. Seems like as good an answer as any for the OP.
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David L
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RE: Electronic Interference?

Fri Aug 31, 2007 2:50 am

Quoting Futurecaptain (Reply 7):
Seems like as good an answer as any for the OP.

Certainly for mobile phones. I'm not suggesting other devices are "safe" but, of the devices the average passenger is likely to bring along on a flight, mobile phones are pretty much in a league of their own regarding the risk of causing interference.  wideeyed 
 
Analog
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RE: Electronic Interference?

Fri Aug 31, 2007 5:09 am

Quoting HAWK21M (Reply 3):

On a commercial flight.Very unlikely.

Well, if FrenchPilot is a pilot or works with commercial aircraft, then it's not so unlikely.

Quoting Starlionblue (Reply 4):

One would thing, but here it is straight from the horse's mouth: http://www.boeing.com/commercial/aer....html

Note that Boeing did not say they did extensive studies, they only investigated specific reports of interference "extensively". They tested in-seat power (part of the aircraft) and cell phones. The cell phone tests did not find any interference.

Boeing has not been able to find a definite correlation between PEDs and the associated reported airplane anomalies.
...
Boeing continues to monitor its fleet through reports submitted by operators and to investigate these reports when possible. The company continues to share its experience and knowledge of PEDs and airplanes with the industry and the public. Boeing is committed to supporting future committee activity and investigations into PED detection devices.

One of Boeing's recommendations is:
Use of intentional transmitters should be prohibited at all times.
Now tell me about Connexion by Boeing.

Airline procedures should be established for PED termination if problems arise.
I'm sorry sir, we have to terminate your device. (Pulls out gun, throws MP3 player to the ground, blasts it to bits.)

If Boeing, or someone else, finds significant interference from "PED"s (personal electronic devices) like cell phones, is there any other course of action other than to remove the aircraft system's vulnerability to the interference? Obviously those devices would have to be turned off, but that could not be guaranteed. In my mind one would have to assume that the devices stayed on and redesign the affected system accordingly.
 
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Starlionblue
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RE: Electronic Interference?

Fri Aug 31, 2007 11:51 am

Quoting Analog (Reply 9):
Note that Boeing did not say they did extensive studies, they only investigated specific reports of interference "extensively". They tested in-seat power (part of the aircraft) and cell phones. The cell phone tests did not find any interference.

Absolutely. As I said before I feel pretty safe.  Wink
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
David L
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RE: Electronic Interference?

Fri Aug 31, 2007 6:15 pm

Quoting Starlionblue (Reply 4):
But interference that is so bad as to be dangerous from a commercial handheld device is unlikely in the extreme. What with multiple signal paths and shielding I feel fairly safe.

I'm pretty much in agreement (not through any industry experience). However, there is anecdotal evidence that mobile phones (perhaps all active transmitters) can at least cause some "disruption". Until that's officially resolved, I'm keeping my phone switched off for the whole flight... especially on one of Pilotaydin's flights, in case he sends Wing to give me a "slap on the head".  biggrin 
 
frenchpilot
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RE: Electronic Interference?

Fri Aug 31, 2007 6:26 pm

Thanks for the answers already given, they turn out to be quite usefull already.
My biggest question I think would be why would some airlines (including mine, and I haven't got a satisfactory answer yet), prohibits the use of "flight mode" on blackberries and cell phone. It is just a constant fight with the business pax cause we know that some airlines accept the use of flight mode, while we don't.

Thanks once again!
"Sur votre gilet vous trouverez un sifflet pour attirer les poissons..."
 
David L
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RE: Electronic Interference?

Fri Aug 31, 2007 6:35 pm

Quoting FrenchPilot (Reply 12):
My biggest question I think would be why would some airlines (including mine, and I haven't got a satisfactory answer yet), prohibits the use of "flight mode" on blackberries and cell phone.

Could it simply be that it's not easy for the cabin crew to tell if a phone that's in use is actually in "flight mode"?
 
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HAWK21M
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RE: Electronic Interference?

Fri Aug 31, 2007 6:50 pm

Quoting Analog (Reply 9):
Well, if FrenchPilot is a pilot or works with commercial aircraft, then it's not so unlikely.

Exactly the point.Any Responsible Pilot would not break the rules & experiment.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
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Starlionblue
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RE: Electronic Interference?

Fri Aug 31, 2007 10:26 pm

Quoting David L (Reply 11):
I'm pretty much in agreement (not through any industry experience). However, there is anecdotal evidence that mobile phones (perhaps all active transmitters) can at least cause some "disruption". Until that's officially resolved, I'm keeping my phone switched off for the whole flight... especially on one of Pilotaydin's flights, in case he sends Wing to give me a "slap on the head".

You should turn it off. But I wouldn't lose sleep over it. Also, there is a difference between "interference/disruption" and "no control followed by a smoking hole in the ground".

Quoting FrenchPilot (Reply 12):
My biggest question I think would be why would some airlines (including mine, and I haven't got a satisfactory answer yet), prohibits the use of "flight mode" on blackberries and cell phone. It is just a constant fight with the business pax cause we know that some airlines accept the use of flight mode, while we don't.

As David says, it's easier to have a blanket ban than to trust customers.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
David L
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RE: Electronic Interference?

Fri Aug 31, 2007 10:32 pm

Quoting Starlionblue (Reply 15):
You should turn it off. But I wouldn't lose sleep over it. Also, there is a difference between "interference/disruption" and "no control followed by a smoking hole in the ground".

In that case, I completely agree.  Smile
 
Analog
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RE: Electronic Interference?

Sat Sep 01, 2007 12:47 am

Quoting HAWK21M (Reply 14):

Exactly the point.Any Responsible Pilot would not break the rules & experiment.

I meant doing the experiments on the ground in the aircraft (I figured that went without saying). Is there anything wrong with making a few cell phone calls while you're in the cockpit at the gate?
 
YYZYYT
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RE: Electronic Interference?

Wed Sep 05, 2007 3:45 am

Quoting Starlionblue (Reply 15):
Also, there is a difference between "interference/disruption" and "no control followed by a smoking hole in the ground".

And I for one am all for maintaining that distinction!

Mythbusters did this one. They found that a cell phone did cause readings to fluctuate on an instrument panel taken from a single engine private plane, but when they repeated the experiment in a modern biz-jet with "sheilded" electronics, there was no apparent effect. THey that the ban was justified based on the possbility.

See:
http://mythbustersresults.com/episode49

PS, and of particular interest to many here, they also busted the myth that a vehicle full of birds will be be lighter if they are all flying:

http://mythbustersresults.com/episode76

signed,

YYZ "may I some day have so much time on my hands" YYT
 
UncleBuck
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RE: Electronic Interference?

Wed Sep 05, 2007 5:58 am

the issue with electronic devices below 10,000' (sterile flight phase) is that in the event of a rejected takeoff or an emergency situation (overrun runway, crash, etc), they a) become missiles and b) prevent you from hearing the instructions of the flight crew. there is obviously no interference as you can use gaming systems, computers, ipods, etc above 10,000' but yes cell phones can theoretically cause interference with the avionics and navigation. do i believe it actually does? no, at least not on modern commercial aircraft. why do i turn my cell phone off? because it's federal law and you won't get service above 1000-2000' anyway and your battery will run down very quickly trying to get a signal.

hope that helps.
 
Analog
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RE: Electronic Interference?

Wed Sep 05, 2007 6:13 am

Quoting UncleBuck (Reply 19):
the issue with electronic devices below 10,000' (sterile flight phase) is that in the event of a rejected takeoff or an emergency situation (overrun runway, crash, etc), they a) become missiles and b) prevent you from hearing the instructions of the flight crew.

I find that hard to believe. Why are heavy books (and pretty much anything else) and earplugs allowed below 10000ft?
 
UncleBuck
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RE: Electronic Interference?

Wed Sep 05, 2007 6:15 am

Quoting Analog (Reply 20):
I find that hard to believe. Why are heavy books (and pretty much anything else) and earplugs allowed below 10000ft?

good point, maybe you should write the FAA about that ?  Smile
 
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Starlionblue
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RE: Electronic Interference?

Wed Sep 05, 2007 11:28 am

Quoting YYZYYT (Reply 18):

PS, and of particular interest to many here, they also busted the myth that a vehicle full of birds will be be lighter if they are all flying:

And they did it empirically, no less. I would still like to think that Grant Imahara did the math and told them the expected result beforehand. It's a fairly straightforward physics problem despite the late thread of 300+ replies...

Quoting Analog (Reply 20):
I find that hard to believe. Why are heavy books (and pretty much anything else) and earplugs allowed below 10000ft?

The power of tradition. Also, books tend to be held in the lap. Cell phones and cameras tend to be held at head level. If there is a sudden deceleration the book will most likely just fly into the seatback in front of you. The cell phone will fly over the seatbacks into the head of some tall person. Or something...
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
UncleBuck
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RE: Electronic Interference?

Wed Sep 05, 2007 1:20 pm

Quoting Starlionblue (Reply 22):
The power of tradition. Also, books tend to be held in the lap. Cell phones and cameras tend to be held at head level. If there is a sudden deceleration the book will most likely just fly into the seatback in front of you. The cell phone will fly over the seatbacks into the head of some tall person. Or something...

thank you  Smile

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