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."

Comments

...really?

[chemicaldave]

There is a growing body of anecdotal evidence

Need I say more?

Re:...really?

[Wyatt Earp]

Have you seen how heavily shielded the cables and connections for PDAs and other PEDs are in US military aircraft?

http://en.wikipedia.org/wiki/File:E-8_crewmembers.JPG

Thats what you need to keep avionics from being disrupted and vice versa according to the DoD, they've done a lot of testing on that stuff over the last 30 years.

Re:...really?

[chemicaldave]

Disrupted from cell phones or enemy weapons designed to disrupt?

Re:...really?

[gstoddart]

This is what I don't understand. With all the discussions over this, how has this not been fully tested and answered? How can we not have a definitive answer by now? And if it has been answered, why it is still being debated?

Because .. testing every possible consumer electronics device which might end up on an aircraft, against all the possible aircraft, and all of the possible variations of an aircraft is damned near impossible.

Some aircraft have been in production for a long time (I think over 40 years for the 747). It's got a whole boatload of variations, and has been tweaked, updated, and re-arranged by different carriers over the years. It's got different generations of avionics, in-flight systems, entertainment systems ... and who knows what else. I've seen the inside of a 747 when it was stripped down to an empty shell ... it's got literally miles of wiring.

Now, think about all of the different models of aircraft in the world. You would need to test 'em all.

I get the impression to be able to definitively say that no aircraft could ever be affected by this, you'd need to do testing of every possible emission from the device to coincide with every possible state of the aircraft ... and some of those interferences might be intermittent or not 100% repeatable, or might be compounded by other factors they can't anticipate.

I don't think anybody has the resources to rule it out ... so they've erred on the side of safety. The sheer cost of trying to test this extensively would be enormous.

And, really, unlike the pharma industry which waits until you can prove that something is causing harm before they pull it, the airline industry is waiting for proof that it doesn't cause harm before they allow it.

Re:...really?

[WillAdams]

Actually, that's more about meeting TEMPEST requirements so as to not emit a signal from which an enemy can derive useful information. Hardening of the avionics is a different thing, and not something one will readily find an image of.

William

Re:...really?

[Cytotoxic]

We do this test every day. On any aircraft of reasonable size, there are at least a dozen cell phones not in the off position during takeoff and landing. Probably more. Most of these jets carry a hundred or more people. Nearly 100% of people carry some sort of electronic devise. Anyone here work in IT? Care to guess how many of your normal users will follow instructions? Does anyone seriously believe they get much north of 90% compliance with the "all electronics must be in the off position" request under the best circumstances? How many rings, pings, and update sounds do you hear on final approach when you come in low enough for the cell signal to connect? I hear so many I don't even notice anymore.

If this were a truly serious problem, we'd have planes dropping out of the sky like rain. I couldn't say that there isn't a potential for a problem. I can say that the risk must be very, very small.

Re:...really?

[uniquename72]

If this were a truly serious problem, we'd have planes dropping out of the sky like rain.

That's like saying "seatbelts are totally unnecessary because I have been driving for 20 years without one and haven't been injured yet".

No, it's like saying, "seatbelts are unnecessary because no one has EVER demonstrably been hurt by not using them." Hundreds of millions of people fly every year, a substantial percentage of them use electronics and don't bother to turn them off (in my experience), and it's still the safest form of transportation -- without a single confirmed death due to electronic use.

I'm not saying that the ban is good or bad, only that your analogy sucked.

this is totally impossible

[Anonymous Coward]

I was told by people on the internet that this cannot possibly happen, so this expert from an actual aircraft manufacturer must be wrong.

Re:And

[Xiph1980]

What's your point? Those are two entirely different things.
Some appliances can handle a firehose spraying directly at them, but break when subjected to water vapor.. Just as related, actually, no even more related.

C'mon...

[jra]

ILS receiver antennas aren't "hidden inside the passenger compartment".

They're "attached to the outside of the friggin airframe".

Any story that gets the details that wrong, that fast, receives no credence at all. And if airplanes are having this much trouble with my 2mw iPad, what the *hell* are they doing about getting hit by 2GW of lightning?

(And don't tell me "Faraday cage"; that protects the occupants, but not necessarily the things connected to antennas outside the cage.)

Re:C'mon...

[Anonymous Coward]

Correction. A bolt of lightning is only 1.21 GW.

Re:C'mon...

[couchslug]

I'm not impressed by the story itself, but do note that ILS testers are operated from INSIDE the aircraft. I've done plenty of ILS ops checks as a Comm/Nav weenie in the USAF.

The airframe doesn't block the signal enough to matter.

Since my being entertained in-flight is of no importance, I leave my electronic gear off when flying and sleep/nap through the trip.

Re:Easy Solution

[roman_mir]

yeah, if applied directly over certain passengers.

Some activities warrant excessive caution ...

[perpenso]

There is a growing body of anecdotal evidence

Need I say more?

Actually, yes. How about something regarding consequences? Say 100+ people in a fragile machine, surround by flammable liquids, moving at a high rate of speed and doing so with limited to no visibility outside the machine having a "mishap" because someone had to check twitter? There are some activities where an excess of caution is warranted, personally I believe that needing to use an ***instrument landing system because of bad weather*** is one such activity.

First hand experience

[Anonymous Coward]

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?

An engineer's reaction

[bughunter]

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.

Re:An engineer's reaction CORRECTED

[bananaendian]

Here we go again, every couple of years an article relating to avionics interference shows up in slashdot and I have to come out of my cave to save the world...

Here is something I wrote back in 2006 about this same issue.

Just because you are 'an engineer' who 'works with RF' doesn't mean you know tiddly about avionics. I actually work at an avionics lab and repair and test these devices and have actually measured RF interference of avionics systems, both on the ground and in the air. Its my job.

As a fellow engineer I could give you a 5 minute brief on how the ILS system works, another 15 to go through explaining all the board level receiver circuits, data busses and another 20 to go throught the navigation computer and autopilot at block diagram level - and afterwards you'd be rolling on the floor laughing to the very idea of a passenger ipod being able to interfere with 'the ILS system'... unfortunately my superiors are hunting me down to lock me back to my cave now.

For others see what I wrote about Ultracrepidarianism