'Flight' Mode on my mobile.
 

I have a Nokia 6233 mobile. It has a 'Flight' mode so you can use the camera, mp3 functions etc without any signals. I noticed though that with that mode selected, although the signal bars disappear, the 3G icon is still on. I don't really understand what 3G is, (I know it is for multi-media stuff like downloading songs) but why is it not a problem when the normal network is?

My company Orange SPV goes into this mode, and it's not easy to get it out of it. Bit of a nuisance!

I should explain that I haven't even tried using it on a commercial flight. I have used it in light aircraft (to take photos etc) when I am flying. Not that I think that a 30 year old C206 has enough electric gadetry to be affected by the phone signals! However, as I am currently flying very close to an international border, the phone has a tendancy to lock on to the foriegn network, which can be expensive if the phone is then used! Doesn't 3G require sending as well as recieving of signals as well though?

The flight mode on your phone does disable all radio frequency signals (inc 3G).
The G symbol just shows a packet data connection was there when the last signal was picked up, no data can be sent in flight mode.

Silent mode covers everything. Just got to think of a way of stopping the throbbing noise on the radio.

IJD - No it doesn't. 'OFF' mode covers everything ... and it solves the throbbing noise on the radio.

The point is that there have been several reports of mobile phones interfering with navigation equipment in flight. No one has pin-pointed the exact reason so the ban is a safety precaution. We're talking about an aircraft here and the safety of the people within.

My ancient car has no iPod docking station so I have a tape cassette emulator that slots into the cassette player. While I am driving along listening to the music I often get the phone 'searching' for a connection. The 'throbbing' noise picked up by the cassette player - a simple magnetically coupled audio frequency device - is deafening. There is no doubt in my Avionics Engineer mind that mobile phones pose a serious hazard to aerial navigation and the ban on their use in and around aircraft is fully justified.

According to the manufacturer of my mobile device, Flight Mode kills all transmitter/receiver circuits inside of the phone. Along with the internal transmitter, all superhets and radio related local oscillators are shut down, including bluetooth and 3G/Data.

I have been assured that the company's phones, when in flight mode, produce weaker and far fewer spurious signals than your average laptop does in lab tests covering comparable bandwidths.

That said, I have personally observed and have been informed by people I trust regarding the numerous and various odd effects a powered up cell phone can have on avionics - often without even being in a call.

FG, do you not think you are painting all with one with your comment that Flightdeck crew leave theirs on.
http://news.bbc.co.uk/2/hi/uk_news/e...re/4898958.stm

I left mine on quite a few times during the whole flight.
Never had any kinf of interfernce-
But I did experience some interference when some in the cabin where receiving calls. This is quite dangerous as this is normally happening close to land, wich is when the telephone is finding the network.

PS i fly 737

Interesting replies; thanks for that explaination, Fargoo. The electric noise from a mobile is an obvious indication of possible interference (i was woken up the other night by the noise through my radio alarm clock (which was off) from the phone sitting next to it on the bed side cabinet. A light aircaft engineer told me that he never believed that they could affect the systems until flying a C182 with a digital autopilot, the aircraft turned (on AP) to the side the mobile was on!
I understand one reason it can be a particular problem with airliners (as apposed to, say, one phone in a light aircraft) is that over 100 phones all trying on maximum power to find a station would add up to a lot of radio power.

PASTED FROM A PM BY A NOKIA ENGINEER WHO WISHES TO REMAIN ANOYMONOUS; THANK YOU! JC
Flight mode
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Hi - an answer to your question about Nokia devices in flight mode -
When you enable flight mode, all external RF-transmitting systems will be disabled. This includes cellular voice & data (2G & 3G), bluetooth & WLAN. The reason for the "3G" icon remaining is more of a software glitch taking a while to be removed. As soon as you switch to flight mode and the bar strength indicator becomes disabled then all transmitters are disabled.
In order to gain worldwide type certification your handset would have been tested rigorously by independent countries authorities to ensure compliance so you can be pretty sure your phone isn't transmitting anything in flight mode.