Most people can't talk on a cellphone and drive safely, study finds [Telecom]

Interesting report though it clearly needs updating from 2001 given all the new Personal Electronic Devices (PEDs) since then.

What struck me as odd is NASA didn't analyze specific cellphone-induced problems such as those caused by GSM devices as we discussed here last year in several threads. As you may recall, I began (at least) one thread after a Nokia guru from their Palo Alto CA lab was visiting my home office and commented the horrible noise issuing from my computer speakers, as we were discussing other matters, was GSM interference; I was relieved to finally learn the problem wasn't an undetected computer virus on one of my Windows systems. Google "GSM interference" (without the quotes) for more info.

During the course of those CDT threads an interesting document was emailed to me from the archives of comp.dcom.telecom and I've saved it here and have frequently referred others to it, especially audio pros and hearing aid wearers who've experienced "unknown" interference. I dread to think what could/might happen to someone with an implanted pacemaker, defibrillator, or other electronic medical appliance given how hearing aids are dramatically affected up to 100 feet (30m). I now place my cellphone far away from my home computers and use a Bluetooth speakerphone when answering calls.

And as reported by the New York Times and posted to comp.dcom.telecom last year. (at least) 3 brands of electronic kitchen stoves have been found to be affected by GSM cellphones and they would be turned-on to high power by a nearby ringing GSM cellphone. A word to the wise: don't place or store non-cookware items atop such stoves.

The laptop is fine; the WiFi on the plane is connected to the net either through satellite or through the 800 MHz air-ground network, which is designed to connect planes to the terrestrial network. Its cellsites are widely spaced to deal with aircraft at cruising altitude.

Not so the terrestrial cellular networks; you could be causing serious and widespread interference whether you have a good connection at the moment or not. At flying altitude, your horizon is about 200 miles. Your phone has an unimpeded line of sight to virtually every cellsite within that 200 mile radius. As a result, your phone will be capable of reaching a substantial number of them at maximum power -- probably all but those directly under you and at the outer fringes of your horizon. Say half of them are compatible with your phone's technology (CDMA or GSM); and half of them receive your phone's signal adequately. When you turn your phone on, it sends out a registration message that is received and processed by hundreds or thousands of cellsites, all of which assume you are in the local area and thus not being served by some other system.

So each system within range attempts to register your phone. Obviously, your phone picks only one to register with. But soon after it's registered in system A, that system may be out of range, given that you are flying at several hundred miles per hour, and it then needs to re-register. If you try to use your phone, it may seem like you are in a "dead spot," but you are actually within range of many systems and not have one locked in because they aren't designed to deal with aircraft. Moreover, if you are using a CDMA phone, the cellsites receiving your signal will reduce the power of other phones in their cell to equalize the signal strengths, which may cause some calls to be dropped -- not just in one cell, but in many cells.

Please don't use cellphones while airborne. Not because it is a hazard to the aircraft, but because it is can be a significant source of interference to terrestrial networks. And it's against FCC rules.

In article ,

There was, and may still be, an _FAA_ rule of long standing that banned the operation of devices that 'might' generate either magnetic or RF fields during certain 'critical' parts (notably take-off and landing) of flights,

*UNLESS* that particular device had been tested in that particular aircraft and found _not_ to interfere with any of the navigation, communication, or flight control systems (I believe there's another 'system' component, too, but the name escapes me.) No provision for 'type acceptance' of either the aircraft, _or_ the 'electronic' device.

There was no hard evidence to say any such devices *were* a risk to flight operations, but there was nothing that =guaranteed= that it _was_ safe to operate such devices. With lives on the line (literally), prudence demands that one take the course of 'risk avoidance'.

For 'less-critical' portions of the flight, airlines _did_ have some discretion in the matter -- (paraphrasing) If they had "hard evidence" that certain devices (or _classes_ of devices) would not, under anything approximating 'normal' circumstances, affect flight operations, etc. they had the _discretion_ to allow the use of such devices, *IF*THEY*CHOSE*TO*. "Absolute proof" was not a requirement (_that_ is impossible, in context), but there did have to be 'compelling evidence' of innocuousness _before_ they had the freedom to make a choice. Needless to say, a lot of airlines found it simpler/easier to 'just say no', than to put in the research to establish, 'conclusively', what devices were, in fact, innocuous.

Title 14 Code of Federal Regulations, Part 91:

§ 91.21 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 of the following U.S.-registered civil aircraft:

(1) Aircraft operated by a holder of an air carrier operating certificate or an operating certificate; or

(2) Any other aircraft while it is operated under IFR.

(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 operator of the aircraft has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used.

(c) In the case of an aircraft operated by a holder of an air carrier operating certificate or an operating certificate, the determination required by paragraph (b)(5) of this section shall be made by that operator of the aircraft on which the particular device is to be used. In the case of other aircraft, the determination may be made by the pilot in command or other operator of the aircraft.