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Letter: "I'm willing to be proved wrong ... but I agree!"

Reader Sid Kalelkar believes airline bans on phone use are more to do with protecting revenues than safety ...

Just read Guy's interesting piece on Airline paranoia ... at NewsWireless.Net and on The Register.

I've been in the IT field the past 28 years of my life and have been dabbling in the wireless part of it the past two years. I presently live and work out from India but have lived in London; technology is the same whether its being used from England, India, US, or Timbuktoo!!

I'm willing to argue on the fact that wireless (at least the kind that's used by Mobile phones and even GSM - 802.x) can in no way affect/harm absolutely anything in the aircraft or interfere with its Instrumentation Landing System equipment.

I personally think this is more to do with Mobile operators (the carriers, telcos, what have you) not being able to bill you when you're up there in the air! Allow me to expound on this.

Let's assume you're a Vodafone subscriber ... living at, say, Wembley and travel every day to your work at South Kensington (SK). I'm sure you're aware that if you started a conversation when you got into your car at Wembley, you'd be able to carry it through till you'd reached SK; how does this happen, seamlessly? Because of the number of APs (those "towers") dotting the area between Wembley and SK ... not only do they ensure that you don't get cut off, but they keep track of the call-parameters to be able to bill you and bill you correctly. So, as you start from Wembley and traverse Stonebridge Park and are about to lose contact with your tower, the next one picks you up ... and so on and so forth, till you've reached SK and disconnect your call.

Each of these towers has a (rated) range of 23 kilometers that is attenuated downwards to 11 km in open areas and about 5 km in densely populated areas (to compensate for more number of Users). Now, remember, these towers work omni-directionally.

If and when you initiate a session (try using your Mobile) when you're up in the air, your Mobile will attract the attention of at least 16 to 18 towers at that point in space wherever you are (even a Super Jumbo flies at a max height of 40,000 feet - that's about 1.4 km). The billing software at the Mobile operators' end was never designed to accept that kind of a scenario - its expecting data on your subscription number (your MAC address, really) from a max of 3 towers (yeps, we still use triangulation techniques to accurately locate a Mobile user - to comply with the Feds/Agencies); so, the billing software gets "confused", trashes the data as "illogical" and billing doesn't get done!

Sure, new software could be developed to overcome this hurdle ... but why do it?!! That costs serious money. Far easier (and, costs nothing!!) to play on the enhanced-fear and insecurity syndrome caused after the 9/11 event. Ergo, get airlines' hackles up by gassing them on their air-safety being in jeopardy should they permit a hapless passenger to so much as switch on his gadget ...

I'm willing to be proven wrong and if somebody else can offer an explanation as how Mobile use could affect aircraft communications systems or their instruments.

All the best.

Sid.