Check the list again.....It says that Mini Disc Players are permitted during flight. I think that the quote from the website has been cut short.

Reasons for not allowing certain equipment is simple. If it TRANSMITS a signal, however small, then it will be banned.

Mobile phones, as an example, transmit a signal which increases in power until it finds a (ground) station. Flying at 35,000 feet this will almost certainly mean that the mobile phone is transmitting at max output. Now consider (as the FAA authorities have to) if all passengers on a 747 use their phone together, the radio interference can and will cause problems for the aircrafts vital systems.

No airline will allow the use of bluetooth in flight. If there's a way to use it with the bluetooth turned off there are a few airlines that allow a GPS to be used.

We've been through this before. Almost every flight has a few phones that are left on. What problems have they caused? To state that this "Will cause problems" is a complete exaggeration. Aircraft travel through radio interference of all kinds all the time with no ill effect.

There is nothing after the word disc on the website, that's where the quote ends. It was not cut short by me.

The link can't be pasted, it's dependant on the page it came from, but if you go to their FAQ's and search for MP3 you can see that that's the entire text.

Please read my message fully. "if all passengers on a 747 use their phone together, the radio interference can and will cause problems for the aircrafts vital systems". I did not state that a few of phones left switched on will cause problems.

I was involved in flight test on a commercial aircraft testing all manner of electronoic devices, including mobile phones. The aviation authorities always assume the worst case i.e. that all passengers can and possibly will at some time try to use their phones at the same time.

Now you and I know that this is very unlikely if not impossible. But the FAA, JAA, CAA and other regulatory authorities make the rules to prevent such things happening.

There are currently two companies that have systems to be installed into aircraft that will act as transmitter/receivers for mobile phones. This will mean that the mobile phones will then only transmit the minimum signal level within the cabin and then send this signal, via satelite to the ground. However, although this system has been tested and shown to be safe the authorities are still insisting on the no phone rule.

You still didn't substantiate in this post that everyone turning on a cell phone on a 747 "can and will" cause interference.

The burden of proof is on the other side...unless you can prove it doesn't, the rule makes sense. This is basic risk management, since the risk is on the interference, not the lack of interference. You do mitigation by having the rule about transmitting devices.

The burden of proof is on the poster who said a 747 with everyone turning on their cell phones "can and will" cause interference. It's not about the rule, I'm asking IFE Wizard about his "study."

While I would be more than happy to divulge all the results from the study that I was personally involved in, due to confidentiality clauses in my contract with the airline and aviation authority concerned, I am unable to do so.

However, plenty of data and similar reports have been published. I would advise anyone interested to visit http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft.

My background is electronics and aircraft systems and not telephone networks. My testing involved mainly the Electromagnetic Interference (EMI) issues.

I must stress here that I am not an airline employee, I am an independent consultant. I have no axe to grind and owe no favours. My only concern is that, like everyone here on this site, I am a very frequent flier and want to carry on flying safely. Anything that can jeopardise my safety is of great concern to me.

The truth is out there.

Right. You're the one who brought up the "results."

Please tell us -- was the study cited above based on .6 watt phones being used by each passenger or the old 3 watt bag phones? There's a HUGE difference. In any event, if the devices are allowed on aircraft there is always a chance that they will be left turned on, regardless of what the rules state.

It would appear that from your questioning you may have some knowledge of mobile phone technology and or electrics/electronics. Therefore I would expect you to understand that electromagnetic interference (EMI) is dependant on both the frequency and amplitude (strength) of the signal. When you ask if the tests were carried out using 3 watt or 0.6 watt units are you referring to the peak power output or average power output (i.e. allowing for multiplex or x 8 channel sharing)?

I am sure you will also know that a GSM and CDMA phone in close proximity will interfere with each other creating a signal at an entirely different frequency � a mutual interference product � that is very close to the band used by the aircraft's GPS and Distance Measuring Equipment (DME).

I must confess that my personal involvement with the in-flight testing took place in 1999 and in all probability did use mainly older technology mobile telephone equipment. However, I have followed the progress of other more recent testing carried out by my colleagues in the industry and have yet to see any clear facts that the more recent mobiles do not pose similar problems in present conditions.

While power output may have been decreased the number of phones now in use has increased many-fold.

I am not posting on this forum to educate or to force my opinions on others. I have just stated my humble, honest opinion. If this should give you or others any problems then I will cease posting. You obviously have a strong opinion on this subject and I respect that.

However, I reserve the right, if I see someone using a mobile phone or other transmitting device on my flight, to personally act to make sure my personal safety is not compromised.

I don't think anyone wants to silence you. Since you seemed to know a bit about the subject we wanted more information. Your response, which was essentially, "I'm sorry -- I can tell you" was not a very satisfying one.I did not know that. Thanks for telling us!

This thread for some merged posts from a thread gone a little off-topic...

Please continue the discussion about interference of electronics on a plane in this thread.

Not to belabor the point, but your unequivocal statement that if everyone on a 747 used their cell phones at the same time it "can and will" cause interference sounded like more than your "humble, honest opinion."

If you can back up that statement with some facts, please do. If not, say so.

I wouldn't suggest you quit posting and have no problems with someone's opinions, but please state them as such.