Mobile phones on planes!?

[SATCO]

So I land at Manchester, England, after 13 and a half hours on board MAS12 from WMKK. We vacate 06R and start taxiing back for stand 212. And despite the cabin crew giving out the "do not use mobile phones until you are inside the terminal", there were at least three people who either (a) switched on their cellphone or (b) started texting or checking their texts or voicemails.

I have a major bug up my ass over two things in life. One is hand baggage which is clearly NOT hand baggage. (See my earlier thread re. the 'Cally Kings' for that missive!)

The other is people that don't do as they're told!

So please can somebody out there explain to me exactly WHY you can't switch on your cellphone (or other portable electronic device), as it "interferes with the aircraft systems"?

WHICH systems does it interfere with and WHY and HOW?

I know it MUST do or else cabin crew Number Ones wouldn't put it out when taxiing back from rollout.

People that disregard the rule should have their mobiles taken off them!

Please can somebody do me the good thing and explain the technical bits re. cellphones and aeroplanes... I am but a simple and humble air trafficker and don't profess any expertise in the technical theatre regarding this bug bear!

Thanks awfully.

SATCO

[tyro]

"I have a major bug up my ass over two things in life."

"The other is people that don't do as they're told!"

Maybe the people you complain of have an equally "major bug up my ass" about being asked to follow bogus and inconvenient safety instructions.

Obviously vacuous safety instructions just serve to undermine the credibility of the crew's important safety directions.

[The Pink Panther]

From my humble understanding it has to do with the microwave waves that mobiles use to transmit, the same ones that no-one can decide whether they fry your brain or not.

A quick google yielded the following

From http://www.meteor.ie/misc/health_science_faq.html:

"Aircraft contain a vast array of complex electronic equipment and communications systems. Using a mobile phone in an aircraft could cause interference to these systems because they are not designed to tolerate such interference. It is for this reason that the use of laptop computers, portable stereos and other personal electronic equipment is also prohibited on board.
The credit card mobile phones now provided on some aircraft do not interfere with aircraft systems because they are wired to a special "base station" that has been designed to safely receive and transmit radio signals in the aircraft."

There's also a page full at:
http://www.geekzone.co.nz/content.asp?contentid=800

[gccpro]

Hi Satco;

Hope you have time to see a doctor about your ass because by 1Q-06 mobile phones will be allowed for use on-board.....
Try and do it as early as you can so it heals in time!:E :E :E

[tallseabird]

Do crew members not use phones while on the ground, I'm sure I have seen them turning their phones off prior to pushback!

[Kolibear]

The systems most at risk by mobile phone usage on board aircraft are...........humans.

If, (and I dread the day this happens) unlimited phone use is allowed on board aircraft I fear the incidence of air rage will rocket.

So can we please carry on with the 'No phones, they interfer with the aircraft' rules in flight for as long as possible and accept that some pax need their phone-fix as soon as they land.

[bookworm]

(Repeating something I posted in Jan04)
The CAA published two papers on the subject:

Interference Levels In Aircraft at Radio Frequencies used by Portable Telephones (http://www.caa.co.uk/docs/50/Gsm_intf.pdf)
looks at the electric field strength in various parts of aircraft caused by a mobile phone in other parts. The highest field strength observed was about 4.5 V/m in the flight deck when a 2W 900 MHz phone was used in the forward cabin of a 737. This would exceed the limits in the certification standard of equipment before 1989, but not more recent equipment. Avionics bay fields reached about 1 V/m.

Effects of Interference from Cellular Telephones on Aircraft Avionic Equipment (http://www.caa.co.uk/docs/33/CAPAP2003_03.PDF)
reports on experiments in which a number of pieces of avionics certified to the older standards were subjected to field strengths of 30 and 50 V/m, equivalent to putting a mobile phone about a foot from the equipment. Unsurprisingly, they found the equipment misbehaved from time to time.

I have to say that this doesn't strike me as a significant body of evidence indicating a problem, but nor is it an all-clear for mobile phones.

[Laundryman]

The way it was explained to me was thus:-

When a mobile phone is switched on it sends out a signal to the nearest base station, a sort of "here I am" message. The further the phone moves from the base station the more power the phone uses to try and reach it, until it gets to full power. Now one mobile phone on a plane would probably not effect any of the planes systems, but envisage 300 mobiles all going up to full power together and things might be a bit different. The answer of course is to build a base station into the aircraft then all the mobiles can operate at minimum power and I think this technology will be coming soon.
The other reason of course is that the cabin staff want your undivided attention for the safety announcements.

[Lucifer]

It is true I believe that their use will involved a base station on the aircraft to avoid full powering-up of the signal from the phone.

I assume that some redundancy would be required to prevent signals suddenly spiking in the event of failure however, potentially causing electronic interference at critical moments, eg map shift?

[airborne_artist]

The bigger problem about using mobiles (as currently engineered) on planes is that the networks are designed for users on/very close to ground level. Once a user is airborne the handset will find a much larger number of base stations that are giving strong signals, and that causes problems in the network, and specifically in the HLR (home location register)- this can (in theory) overload that element, and so reduce the capacity/capability of the network.

[guclu]

Hi,

an extract from Airbus 340 FCOM Bulletins:

A study has been conducted by an RTCA (Radio Technical Comission for Aeronautics) special commitee.

- The conclusion is that the probability of a passenger-operated device interfering with the ILS localizer during a typical flight is about one in a million.

Airbus Industrie recommendations is that no portable device should be used during take-off and landing.

Hope it helped.

[Pub User]

I have a very good friend (!!) who has neglected to turn his phone off occasionally when airborne. When he subsequently remembers and reaches for it to turn it off, at cruise altitude, it normally has no signal.

He is, thus, a little baffled at the supposed future relaxation of the rules, as the things don't work up there anyway.

[Captain Stable]

On the contrary, P.U., they work very well. In fact, they work harder than ever before, trying to search for a signal. That they have little success is not the fault of the mobile itself.

All the more reason to obey the rules and switch them off.

With that, I am closing this thread. There have been threads on mobiles ad nauseam. Do a search.