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Personal Electronics May Indeed Disrupt Avionics
mattrwilliams writes "There is a growing body of anecdotal evidence that points to personal electronics being a real issue on board planes. Dave Carson of Boeing, the co-chair of a federal advisory committee that investigated the problem of electronic interference from portable devices, says that PEDs radiate signals that can hit and disrupt highly sensitive electronic sensors hidden in the plane's passenger area, including those for an instrument landing system used in bad weather."
There is a growing body of anecdotal evidence
Need I say more?
I was told by people on the internet that this cannot possibly happen, so this expert from an actual aircraft manufacturer must be wrong.
Correction. A bolt of lightning is only 1.21 GW.
I had always been suspicious of the reality of small electronics and avionics interference, but now I have some first hand experience--I fly a small airplane (a Decathlon). Granted, it has much different RF characteristics than a large airliner. Like most airplanes, it is equipped with a transponder that encodes the airplane's altitude and transmits it when the air traffic control radar paints the airplane. Sometimes when my iPhone is turned on in the airplane, the altitude reported by my transponder varies wildly by several thousands of feet, and air traffic control tells me they are getting spurious signals. One day when this was happening, I thought ah heck and I turn off the phone, and the transponder settled down. I turned it back on, and the transponder started going wonky again. I've reproduced this on a few different days and most days with no issues with the phone turned on. I'd say it's 20% bad/80% good. I haven't figured out what conditions cause this to happen or not--could be poor equipment installation. Anyone else with actual experience of something like this happening?
As an engineer who designs and integrates RF systems every day, all day, I have two impressions. And as a systems engineer, I'll describe them in terms of the two elements of risk: probability and impact.
FTFA: "In other events described in the report, a clock spun backwards and a GPS in cabin read incorrectly while two laptops were being used nearby."
First: Crap like that ain't supposed to happen. An airplane designed and built to standards for commercial passenger service must meet standards for electromagnetic susceptibility, interference tolerance, workmanship, etc. It's not the passengers' fault that things like that happen. Nor is it the direct fault of the manufacturer of the electronics that passengers carry. If something is that mission critical, and the cost of failure is measured in human lives, then engineers, inspectors, regulators, and operations crew damn well better make sure the likelihood of failure is as close to zero as can be.
Second: I know damn well that grounding and shielding is one of the most difficult aspects of any high-frequency electronics system. It's difficult to design, grounding and shielding design rules aren't generally taught as part of undergraduate EE curriculum (much less Aeromechanical, CS, etc.), and the manufacturing techniques are prone to failure and not easy to inspect and test. Therefore, statistically, a passenger that travels one or two times a year is likely to board a plane with a design flaw or manufacturing/maintenance flaw at some point in their lifetime. This doesn't mean they're going to notice it, or even have any effect on the flight, much less cause an emergency by forgetting a powered-up iPhone in their carryon. But the likelihood of failure will never be zero unless the passenger obeys the rules and turns off their devices.
So, turn your shit off when so instructed.
And consumer electronics designers: please give the consumer a switch that allows them to turn their shit off... not standby, but OFF.
I can see the fnords!