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Britain's CAA Considers Laptop Ban on Commercial Aircraft
hayb writes "An article in Britain's The Register claims that NASA and United Airlines have conducted tests on various aircraft and have found that ultra-wideband (UWB) devices "knocked out" collision-avoidance systems and impaired instrument landing systems.
It states that the blanket ban on all devices in necessary because flight crews do not have the knowledge to differentiate between standard notebooks and ones with UWB devices."
...but I'm still a bit amazed at how lightly people take issues like this.
Your sitting in a metal crate with two giant combustion engines delivering an insane amount of power to get you off ground.
A plane consists of several thousand electronic, mechanical, and electromechanical systems, a zillion bolts and hundreds of tonnes of lightweight metal. And any single part of this giant system might fail at any time.
The fact that accidents don't happen more often than they actually do must be considered an engineering miracle.
So, you can't smoke and sip a gin&tonic while writing some shitty design document nobody cares about and which you might as well write when you get there?
Boo-fucking-hooo
Read a book.
If this were really an issue, we would be seeing terrorists with small devices built into cell phone cases that were built using a switch, a battery, a capacitor, a coil, an electromechanical relay, and a large antenna loop: a spark gap generator, of the type one makes from Radio Shack project kits.
;^)).
Or, they would just have cell phones, since they are also supposedly a source of interference with something other than AirFone revenues
In reality, this article is _mostly_ bogus.
The ILS (Instrument Landing System) is vulnerable to electronic interference, mostly because it is an incredibly ancient implementation, and has not yet been replaced with anything designed in the last two decades.
The antique ILS in even the most modern aircraft is why you can't use electronic equipment during takeoff and landing (landing is obvious; so's takeoff, if you realize that it might have to be aborted, in which case it turns into a landing).
Most airports, however, are in urban areas, with a high telephone cell density. If this were ever a real issue, we would see aircraft dropping out of the sky as they flew over any urban area. SFO, PHX, and SLC tend to have a higher than average instrument requirement (the first for fog, the second two for temperature inversion based wind shear; want to vomit? Fly Tucson to Phoneix. SLC also has snow visibility issues in winter). For most airports, the systems are largely ignored. SLC has an upgraded system that ~60% of modern planes can use, actually; it's a deployment issue.
The TCAS (Traffic Collision Avoidance System) is actually based on paired receivers. It's succeptable to powerful broad-band interferences; "powerful", in this case, means "orders of magnitude higher than the those currently permitted for use in UWB devices".
The failure you would see (and you would probably need a specially manufactured transmitter to see it) would be a 180 degree polar flip (i.e. if the transponder you cared about were 23 degrees down and 17 degrees right, it would read as 157 degrees up and 163 degrees left). This actually happens a lot, and the hardware is built to automatically compensate through multiple samples (i.e. sustained interference is required).
The fix for this is to go to trios instead of pairs of receivers.
As we saw just the other week, though, TCAS itself is generally ignored in favor of ground instructions, we lost two planes in a collision in Germany specifically because TCAS was ignored.
Given that TCAS is almost never used, anyway, because the controllers keep the planes far enough apart, the interference is isn't likely to be an issue.
In any case, I think the overall concern is a result of the fear of out-of-spec devices, which met emissions at the time of manufacture, and have since, for whatever reason, ended if with a much higher signal strength.
Personally, I think they are worried over nothing: it's just an uncommenly slow news day, what with most of the U.S. shut down for Labor Day...
-- Terry