LHSebi
Topic Author
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Scanner Influence On Aircraft In Flight

Thu Apr 15, 2004 4:15 am

Hello,
I was just wondering if someone can explain the effect of using a radio scanner (to listen to ATC) on an aircraft? Does it really matter if you use it? I mean, the real radios of the pilots cant work much different, or? I don't mean a transceiver, but just a scanner. Any information is appreciated. Thanks!

Sebastian
I guess that's what happens in the end, you start thinking about the beginning.
 
galaxy5
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RE: Scanner Influence On Aircraft In Flight

Thu Apr 15, 2004 5:28 am

In all actuallity it doesnt effect any instruments in the aircraft. We use radio's, handhelds, scanners, laptops etc all the time and they dont create any notiable interference what so ever.
"damn, I didnt know prince could Ball like that" - Charlie Murphy
 
FredT
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RE: Scanner Influence On Aircraft In Flight

Thu Apr 15, 2004 4:52 pm

In actuality, it can’t be proven that scanner X will not affect the avionics when used in position Y under conditions Z1, Z2 and Z3. It has been proven that scanners and other handheld electronic equipment can affect the avionics. The report is linked in earlier post I made on the subject, use the search function.

Uncertified equipment might or might not be shielded. A unit may have been shielded when shipped but broken since, not affecting the function but ruining the shielding. Scanners and many other devices contain oscillators which may well emit at frequencies used in aircraft.

Using electronics in the cockpit is one thing. If the nav equipment starts acting up, that laptop the F/O is using will come off. I do hope it will be off when they’re shooting the approach to Innsbrück too... The same will not apply to your scanner back in the cabin.

Saying “we use it all the time and it has never done any harm” is like saying “I drive over this railroad crossing withouth looking at the signals every day and I’ve never been hit by the train”.

“I’ve never found any water in the tanks so I don’t check them anymore”. Those who are lucky get to make that statement in an accident report, and it is really the same thing.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
rendezvous
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RE: Scanner Influence On Aircraft In Flight

Fri Apr 16, 2004 6:42 am

Yeah "can" interfere, not "will" interfere. The policy is better safe than sorry.
 
avioniker
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RE: Scanner Influence On Aircraft In Flight

Sat Apr 17, 2004 6:18 am

Go get 'em Fred!!!
I'm getting so sick of people trying to get around rules they don't like because they think they're too important to be bothered.
Scanners emit IF radiation. ALL receivers emit IF radiation. Aircraft receivers are shielded to prevent that radiation from interferring with other avionics on the same aircraft. Scanners are not. If the IF is in a location where it may be picked up by a unit momentarily using the same frequency pattern it WILL cause interference.
TURN THE CRAP OFF WHEN THE F/A TELLS YOU TO!
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
LHSebi
Topic Author
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RE: Scanner Influence On Aircraft In Flight

Sat Apr 17, 2004 7:07 am

ehm...Avioniker:
Just for your information, I do not even own a scanner at the moment, and thats also why I have never used one, let alone in an aircraft! I was just curious about this as I have recently read about lots of people using them in aircraft, and was wondering. Before you go nucking futs, have a thought...

Sebastian
I guess that's what happens in the end, you start thinking about the beginning.
 
SailorOrion
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RE: Scanner Influence On Aircraft In Flight

Sat Apr 17, 2004 5:14 pm

A real scanner (without additional functions) is a totally passive device, and will therefore not interfere with any systems. As soon as it emits electromagnetic waves, there's muddle.

SailorOrion
 
FredT
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RE: Scanner Influence On Aircraft In Flight

Sat Apr 17, 2004 5:38 pm

SailorOrion,
didn't you read what I posted above?

Sorry, but the big bullshit flag has to come out regarding your statement that a scanner is a passive device. I did explain why.

If you think I am being harsh, it is not directed at you but at the people who might read your erroneous statement and decide to use their scanners in flight.

/Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
thegreatchecko
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RE: Scanner Influence On Aircraft In Flight

Sat Apr 17, 2004 11:25 pm

Just a question: What is the difference between a scanner and a handheld radio used in many GA aircraft?

I'm just having trouble grasping how a scanner in row 16 "could" cause interference in a large transport category aircraft, but little is said about using handheld radios in the cockpit of GA aircraft (which in my opinion have avionics that would be a lot more susceptable to interference).

GreatChecko
"A pilot's plane she is. She will love you if you deserve it, and try to kill you if you don't...She is the Mighty Q400"
 
fspilot747
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RE: Scanner Influence On Aircraft In Flight

Sat Apr 17, 2004 11:32 pm

I know of one affect of using a scanner on board. It involves being handcuffed to your chair and arrested on arrival  Big grin



FSP
 
FlyboySMF2GFK
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RE: Scanner Influence On Aircraft In Flight

Mon Apr 19, 2004 6:21 am

If you own a scanner (as I do), run through the manual and look at the list of frequencies that it will "erroneously" stop at due to it picking up it's own emitted RF. Heck, just try it - there are a bunch of empty freqs that it will stop at and it's not just a dead carrier from the outside. They may not "transmit," but they will emit.
 
airplay
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RE: Scanner Influence On Aircraft In Flight

Mon Apr 19, 2004 6:38 am

What is the difference between a scanner and a handheld radio used in many GA aircraft?

Comparing a GA airplane to the average airliner? Chances are, on several GA airplanes, the only electronics on board are contained in the handheld you speak of.
 
rducky
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RE: Scanner Influence On Aircraft In Flight

Wed Apr 21, 2004 8:16 am

To date I always bring my scanner onboard, before going to my seat I pop my head into the cockpit and talk with the flight crew and ask them they mind me using it, they laugh and say no problem, so far I haven't met a flight crew that said no, although I can't speak for all the crews, but for me I show them a little respect and gratitude for their hard work, and all is well.

Rducky
Up Up and Away
 
Twistedwhisper
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RE: Scanner Influence On Aircraft In Flight

Wed Apr 21, 2004 8:57 am

And that's the way it should be.... if the F/O:s or F/A:s say that it's alright to use it, then OK.... if they tell you to shut it down, don't ask why...
Same goes with GPS devices (althought your fellow passengers might feel a little uncomfortable sitting next to you when holding a gps in your hand... it's these terrorist focus times), if they tell you to shut it off, don't argue.... and don't turn it on before you've asked...

I can see the impact of a cell phone in the cabin, just put your cellphone ontop of your monitor and place a call to it.... haven't seen that with scanners...
Read between the lines.
 
rducky
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RE: Scanner Influence On Aircraft In Flight

Wed Apr 21, 2004 11:37 pm

I also agree if you are told to turn it off by all means do so without hesitation.

Up Up and Away
 
avioniker
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RE: Scanner Influence On Aircraft In Flight

Thu Apr 22, 2004 12:29 am

Once and for all:

LHSebi, don't be so thin-skinned. This subject has been discussed to death and some of us that have to work on the avionics and constantly explain to the aircrew members what is and isn't wrong with their planes are getting a bit fed up...

Rducky, Pay attention!

Title 14: Aeronautics and Space
PART 121—OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS
Subpart K—Instrument and Equipment Requirements


Previous | Next


§ 121.306 Portable electronic devices.
(a) Except as provided in paragraph (b) of this section, no person may operate, nor may any operator or pilot in command of an aircraft allow the operation of, any portable electronic device on any U.S.-registered civil aircraft operating under this part.

(b) Paragraph (a) of this section does not apply to—

(1) Portable voice recorders;

(2) Hearing aids;

(3) Heart pacemakers;

(4) Electric shavers; or

(5) Any other portable electronic device that the part 119 certificate holder has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used.

(c) The determination required by paragraph (b)(5) of this section shall be made by that part 119 certificate holder operating the particular device to be used.

[Doc. No. FAA–1998–4954, 64 FR 1080, Jan. 7, 1999]


Incidentally, row 16 is a very good place to cause interference. Especially in a 757 as that is where the fuel quantity wiring enters the fuselage and has many shield junctions which may become defective with age.


One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
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Starlionblue
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RE: Scanner Influence On Aircraft In Flight

Thu Apr 22, 2004 1:45 am

Rducky is paying attention. He is also asking for permission. If the pilots don't mind, what is the problem?

If you can't get hold of the pilots, or don't have explicit permission in any other way, leave your scanner off. It's not rocket science.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
avioniker
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RE: Scanner Influence On Aircraft In Flight

Thu Apr 22, 2004 2:36 am

Okay
Nobody seems to be able to read the part about the FAR part 119 Operator testing requirements.

"(5) Any other portable electronic device that the part 119 certificate holder has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used.

(c) The determination required by paragraph (b)(5) of this section shall be made by that part 119 certificate holder operating the particular device to be used."

What that means is that unless the operator (Airline) has tested the specific device or has certified test results on file from an agency like the FCC they can not approve or allow its use.
I promise you that there are very few operators who have tested all the scanners available to the public. I also promise you that generally available scanners are not constructed to meet airworthiness requirements. (That's in the US. The requirements in Europe [and Germany in particular] are much more stringent and the general quality of radio receivers sold there reflect those standards.)
Considering that the scanner has an AF amplifier so you can hear the signal, and modulators to convert the RF to IF to AF they are potential interference causing devices. That means the Captain is operating outside the limits of his authority. It doesn't matter if it's because of ignorance or simple disregard for the rules. He can't say it's okay without a list of approved devices in his hand. There's simply too many to count.

NASA and the British authorities have been doing some tests with some disturbing results. You should Google the subject.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
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Starlionblue
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RE: Scanner Influence On Aircraft In Flight

Thu Apr 22, 2004 5:59 pm

"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
musang
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RE: Scanner Influence On Aircraft In Flight

Thu Apr 22, 2004 6:50 pm

Any Pilot who says Yes to a request to use a scanner obviously hasn't witnessed the effects.

But fundamentally, how many pilots do you think there are who actually know as much about the problem as Avionics Engineers?

I used to be a severely afflicted spotter etc., and would have loved to listen to a scanner when I went flying as a passenger, so I sympathise. But I always assumed there was a good reason for the rule, and didn't have arrogance to think I knew better, after hearing the cabin PA about electronic devices.

As a pilot, I have taken the trouble to seek out and read reports of investigations/tests into radio interference. If the "Yes" pilots had bothered to do the same, they would become "No" pilots!

I know most of us think we're God, but a pilot's expertise (unless he's also a licenced technician, and there are some), is in operating the aircraft. Generally, we know enough about its systems to operate it safely and efficiently, plus deal intelligently with any problems we might find.

This level of systems knowledge merely scratches the surface of an engineer's.

So I would suggest that a pilot who says Yes is under delusions of complacency. See FredT's brilliant analogies in Reply 2!

Regards - Musang
 
iakobos
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RE: Scanner Influence On Aircraft In Flight

Fri Apr 23, 2004 9:52 pm

SailorOrion
any current passing through a conductor produces a magnetic field, there is no such thing as a "passive" electric device. Even pacemakers, earing aids, electric shavers on the "authorized items" list are not.

FlyboySMF2GFK
yes, even the most carefully designed RF device has its own problems. Signals of various frequencies are created inside the apparatus, they mix with each other, and the results of these combinations can indeed fall into the frequency spectrum the device is supposed to be able to receive, and consequently block one or more channels/freqencies.
These are internal interferences between circuits separated by millimeters and even less.

If a scanner can interfere with any other device ? I am not going to elaborate now, but the answer is NO.....unless the two devices are right next to each other and one is susceptible to be sensitive to the interference at that particular frequency (or frequencies). Statistically, one has more chance to win the lottery, but still, it is not totally impossible.

For the (half)technically interested: see
http://www.airliners.net/discussions/tech_ops/read.main/83985/6/
Rgds
 
FredT
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RE: Scanner Influence On Aircraft In Flight

Fri Apr 23, 2004 10:01 pm

The noise frequencies do not only fall within the range a device is designed to receive. In fact, they can fall far outside it as well.

Googling on e g heterodyne receivers should give interesting links.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
KALB
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RE: Scanner Influence On Aircraft In Flight

Fri Apr 23, 2004 11:04 pm

When boarding an airline flight consult the in flight magazine and find the section on permissible and prohibited electronic devices. On all flights I have been on in the last four years, scanners are on the "prohibited" list. I choose to obey, as much as I would love to listen to ATC while in flight.
 
iakobos
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RE: Scanner Influence On Aircraft In Flight

Sun Apr 25, 2004 3:22 am

FredT: what is a "noise frequency" ?
We usually call "noise" whatever energy is radiated outside of the intended spectrum window (=bandwidth) where the useful signal takes place.
The biggest noise producer in our celestial system is the sun.
Connect two pieces of wire to a neon lamp and try it in the vicinity of a powerful transmitting station (LW or MW or SW broadcast, VLF submarine comms, etc...), chances are it will glow. (quite a few Volt per meter at quite a distance)
See the difference with a very highly improbable interference from a scanner local oscillator (some nanoVolt per meter at very close proximity) ?

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