Tam’s comment on the FAA reviewing policies on electronics use on planes:
While I’m sure it’s possible that playing with your vaccuum tube tester in the smoking section of a Convair 600 would mess with the LORAN-A receiver something fierce, it’s getting harder to buy into the whole idea that the tiniest electrical impulse in the cabin will send a modern jetliner veering wildly out of control to crash into the nearest orphanage or oil refinery when the pilot’s approach plates are on a frickin’ iPad.
We’d almoset have enough to run this experiment here at SNBQ. I’m pretty sure I’ve seen a LORAN receiver in Jason’s basement, and he probably has a vacuum tube tester somewhere down there too. Unfortunately, the smoking section on a Convair 600 is probably not to be found even sunning itself in a desert somewhere.
We don’t have to presume, we can just test the output frequencies and output levels of the intentional and unintentional radiation from personal electronic devices on the flight equipment of currently operating passenger aircraft.
Can they effect flight operations in a way that could cause a disaster? Both the UK CAA and Nasa say yes. Next question?
Note: iPad logbooks have their radios turned off. Do you want to bet that all of the passenger’s one do?
Even then, there’s no guarantee that the emissions from the various electronic components and clocks won’t cause interference. Having participated in an EMC noise floor test, it’s absolutely amazing how you can pick up basically every electrical impulse from quite a distance with the test equipment…
As someone who’s been a part of EMC testing, I can say yes those little electrical impulses can in fact cause erratic operation of the comm and nav systems on aircraft.
I’ve personally seen a standard issue Dell laptop cause interference in fully FAA TSO’ed nav systems on a Cessna Citation jet. When you’re sitting on the ground in N. AL, fire up the laptop and suddenly the nav system says you’re @ 10k feet above Nashville, you’ve got a problem…
Yes, and I’ve done EMI/EMC testing before as well. The problem you have in that instance is NOT in the Dell laptop…
That’s a failure of the TSO process. They need to tighten THAT up, instead of putting in stupid rules about using consumer electronics (which DO have some EMC requirements of their own) on a flight.
Huh, kinda like needing to look at how we deal with Mental Illness, rather than making stupid rules about gun ownership…
From an airworthiness perspective I disagree. EMC issues are as sensitive to installation details as they are to vulnerabilities of the boxes themselves.
There’s a reason that we do as a minimum source victim testing even when we move boxes around on the military side. Even a change in wiring length can generate an EMC issue and that’s with tightly controlled configuration and operational restrictions.
Now imagine that you’re talking an airliner with who knows what variation in maintenance processes. Remember, theres a lot of room for variation in the FAA standards. Now also imagine that everybody and his brother is bringing different devices, manufactured to different standards, operating in different configurations and there really is no telling what kind of interactions you’ll get.
And as far as the FCC radiation requirements, at least as far as Part B goes, they’re a joke.
And no, there is no parallel between airworthiness and anything to do with firearms regulation. Airworthiness is fundamentally a data driven excercise and you don’t approve things based on nothing but hope and assumptions. Orgs that did that in the past have gotten a lot of people killed…
We don’t have to imagine. Its already happened without any harm.
OK. I apparently wasn’t clear in my analogy, and we’re talking past each other.
My point was that the problems you’re describing can be designed (and built) away. Filtering works, though it’s expensive and potentially heavy–not good for business in the aircraft industry. The testing that passes a “box” which is vulnerable to external interference as airworthy should be tightened, instead of trying to control external sources.
The analogy was exactly in line with your complaint about the parallel between airworthiness and firearms regulation. Rather than trying to control access to guns over the population as a whole (external interference on aircraft systems), society needs a better solution to “crazy people” (tighter airworthiness standards for a “box”). Similarly expensive and “hard” to make work.
And yet, no plane has ever crashed because of it.
Nope. I would also like to note that various Muslim countries have access to actual copies of EVERY aircraft model currently being flown.
If it were actually possible to affect the operation of even one of them via electromagnetic interference, 6 guys named Mohammed would board a flight, seat themselves throughout the plane, and put their laptops with extended life batteries in the overhead bins. Those laptops would show no power lights, no wireless network lights, nada.
However, when the GPS card detected that the plane had reached a certain altitude, those laptops’ wireless cards would start broadcasting full power on the exact frequency needed to cause maximum interference and crash the plane.
If they could move the controls as Stranger claims, then they could work out the exact pattern needed to fly the thing into the White House.
The word is BULLSHIT.
In the airworthiness world that I live in, saying “It hasn’t crashed yet” without having substantiating test data to back it up just means you’re on the lucky side of the probability curve…
Maybe, but we also have at least 10 years of test data without a single incident. I think that’s enough.
In a 1996(95?) experiment, the FFA landed a 727 at a remote airport, and had an employee make a cell call. While the phone was an older analog model, the flaps and other flight controls were observed moving “on their own” when the man was talking.
Digital cell phones are reportedly somewhat less prone to disturb flight controls but more likely to disturb instrument settings.
Personally, I would not care to fly when cell phones are in use.
Stranger
Except you almost certainly have. I’ve left mine on because I know they rule is dumb. And I’m sure I’m not the only one who has done that, intentionally or unintentionally.
Who’s designing the electronics for these planes? Don’t they know about thunderstorms, or the powerful VHF/UHF signals emitted from the tops of the towers many flight lanes pass close by?
…If you can harden aircraft systems against that, what’s a little Wifi/Bluetoothage? Sure, it’s closer, but it’s way lower power.
Celphones are another story — it’s not the airplane so much as it is all the cells your phone sees, and the speed with which it moves across them.
Oh, and the tube tester/Loran thing? Find a tube that arcs internally under test and you can take out navs *and* comms! …Good luck finding a place to plug the ol’ Hickok in.
Good God! Don’t tell the idiots at the TSA that we can bring down an airliner with our cell phones. We’ll be reduced to spider man comics on our flights.
OOh, a jobs program for the struggling comics industry!
My understanding is that the big fear is electronic emissions may interfer with the localizer and glide slope instruments on a hard ILS approach. If the auto pilot is slaved to those instruments, that will make for a very bad day, particularly in a cat 3 approach. If the pilot is flying manually and either the localizer or the glide slope isntruments are reading incorrectly, you don’t really know where you are in the sky. In other words, you are on a landing approach in a fog and you really do not know where the runway is.
Here’s your plane: http://www.abpic.co.uk/photo/1139646/ Don’t know how recent the photo is. But that grass is getting rather long.
On closer examination it says right there. Well, they may have moved it since 1978. Oh well. I tried…
They allow the use of WiFi on aircraft now. I blew a couple of bucks on it when I flew frpower. to ATL a couple years back for fun. Part 15 or not, there’s no telling what some insufficiently QC’d part from a PLA-owned factory might do.
That having been said, the reason it didn’t matter how many FCC commissioners Lightsquared jawboned was that there was no little liver pill they could have pulled out to magically immunize every GPS receiver against interference from Lightsquared’s licensed bands; even if the receivers had been properly shielded against the radiation in the adjacent spectrum, there’s a difference between orbital sources and terrestrial ones as far as distance and poorer