The F.A.A. says it will take a “fresh look” at the use of iPads on planes. (bits.blogs.nytimes.com)

But whatever it is, you don’t want to do all your tests in a “simulation,” then have some scientists say “Oops, our bad, we forgot to simulate lower pressure or increased gamma rays or what-have-you,” when we can simply fly the device and all of our testing equipment.

Now excuse me, I have to return to preparing for the Invasion of Moghron from the Frozen Seas of Neptune

What confuses me is why they don't ensure that planes' electronics are properly shielded rather than testing a bunch of electronics that emit very weak to weak EM. If a cell phone could create problems for a flight during take-off, what about a lunatic pointing a HERF weapon at the plane?

It's the "unknowns" not accounted for in the models that are the (potential) issue. If you have time read through this Ars Technica thread where a bunch of these questions are hashed out: http://arstechnica.com/civis/viewtopic.php?f=23&t=116333...

For those without the time, I'll highlight one post from page 5:

"Unintentional radiators.

The reason they ask you to power down ALL electronics, and not just turn off radios, is that the oscillators (the clock that runs all digital devices) on the circuit board can act as miniature radios, in and of themselves, via clock signals on circuit traces. They emit at the clock frequency, and in some cases many higher level harmonics of those frequencies.

As I've stated several times, it's actually pretty easy to mitigate against known frequencies and signalling techniques...it's the ones you don't know about that are the problem. EMI can be downright spooky.

As an example: I was once testing a medical device (for the Medical Device Directive) that was required to failsafe, since it would literally be touching a patient (it was a combination pulseoximeter and a few other things all rolled into one.

There were numerous tests for both emissions and immunity, and things were going along ducky until we noticed two separate failure modes that weren't considered failsafe. At the time, we were testing ESD immunity up to 20kV. It would pass one time, and not another. We thought maybe we had a bad unit, so we got a few more from the manufacturer. That entire week we kept trying to figure out how to make the failure repeatable, without luck. My coworker and I went in over the weekend, and could simply not make any of the units fail at all, with the exact same test.

That's what triggered our thought process...what else could be causing the issue during the work week but not on a weekend?

Other immunity tests! Turns out, a dozen or so meters away, a different device was undergoing a different test...that wasn't required for the MDD. It was a conducted immunity test (it may have been Electric Fast Transients, can't recall) but the actual test signal was leaking out of that lab, and into our lab, via AC lines in the building. Our chief engineer submitted a proposal to add whatever test it was to the MDD, but I don't know whatever became of that.

I've seen simple clocks inside electronic gear cause CPUs to go haywire...in effect a single system interfering with itself. I've also seen extremely low power, yet very high frequency harmonics invade and corrupt function of another device, several meters away."

In reality, there almost always is."

if someone's a frequent flyer, the routine is going to get monotonous. You'll need a moderate stack of magazines if you're stuck on the runway for another half hour. Change planes once or twice, and you'll really be wishing you had a lot more reading material. magazines are generally half ads, so you'll get tired of those reading those.

Overall, I sort of agree with you - it seems a little over the top, but it's probably not unreasonable for many people. A stack of newspapers would be lighter, but they're usually too big to deal with for extended reading in economy/coach seats.

But from what I understand a big reason for the "taxi, takeoff and landing" routine is that somebody completely absorbed by their iPad is the last thing the crew want when things to pear-shaped, and when this happens, it's at these points rather than on cruising altitude. Now of course you might the same argument for a book (although it's a strong one for music players), but just my $0.02

Here's a sampling of interference events: http://asrs.arc.nasa.gov/docs/rpsts/ped.pdf (edit: only some of them are about EMI interference)

Instruments acting up won't automatically cause a crash. But they may contribute to the accident (ref AF447)

http://www.cvel.clemson.edu/pdf/nasa-rp1374.pdf - some examples of what lack of EMI shielding can do.

• People hate having to listen to 1-sided conversations

• The phones were confusing the network - they would switch to a new cell tower every 15-30 seconds.

Both valid arguments if you ask me. Not sure if these complaints were drawn from reality or hypothetical problems - was there a period of time when you could actually use your phone on a plane? I'm pretty young so I don't remember back to the first cell phones.

Not at all: http://arstechnica.com/civis/viewtopic.php?p=22383605#p22383...

But yeah, it is 2012 get with the program.

A better question to ask would be probably: should they test multiple devices in addition to single samples in order to catch more interaction patterns?

And... clients/bosses complain when testing takes a long time, which is what we're doing here to the FAA.

Given how many flights happen, with a variety of devices, you might think that with some extra devices and controlled test procedures, the FAA would be able to gather 'real world' test data (their devices, their tests, real flights, etc.) and make conclusions over the past 3-5 years.

MAYBE... then issue guidelines (or even paid-for device approval processes). Would Apple pay a few million to get an 'FAA-approved' sticker for iPads and iPhones? If there were specified guidelines and a testing procedure, more companies might work in that direction. I'd imagine there are guidelines, but not being in that industry, I don't know how easy to access they are. If there were public knowledge, I'd imagine device manufacturers already promoting "meets FAA guidelines for xyz", but since we don't see that, I have to assume they're not easily accessible.

In this case, we also know from experience that small devices like iPads do not cause high levels of EMI. Once we have tested a dozen models on a dozen planes and had successful results on all 144 tests, there is no need to test further models. This is unlike software, where of 144 unit tests, a good percentage are almost guaranteed to fail at some point in time.

"For example, if the airline wanted to get approval for the iPad, it would have to test the first iPad, iPad 2 and the new iPad, each on a separate flight, with no passengers on the plane."

Performing the tests would be insanely bad PR. An official has to approach someone going on a flight and say "we think this device will crash the plane, but We're not sure, would you mind playing with it during theft flight so we can see if the plane you're on falls out of the sky?". Panic would ensue.

b) If something goes wrong with your avionics, you can turn off the iPad. If something goes wrong on an airliner, the pilot can't quite as easily figure out whose iPad is causing the trouble.