Agree on all accounts except one: "Envision future airplanes with RF detectors at every seat. If emissions were detected, a red light next to the isle seat could turn on."
It isn't the intentional emissions that are a hazard to the aircraft; it's unintentional, and those are too low-level to register in an rf detector. Ken Javor Phone: (256) 650-5261 > From: Pat Lawler <[email protected]> > Date: Mon, 19 Mar 2012 07:13:31 -0700 > To: Ken Javor <[email protected]> > Subject: Re: [PSES] New immunity testing by the FAA in the future? > > I'd be in favor of the FAA testing airplanes & PEDs looking for > possible problems. If no problems were found, maintain the current > regulations. If there were significant problems, the restrictions > could be 'racheted up'. > Envision future airplanes with RF detectors at every seat. If > emissions were detected, a red light next to the isle seat could turn > on. > > Ken - concerning your ground-based testing method, I envision an > airframe with no seats, and a gigantic belt-driven positioner. It > would move the PED from left window to right window and down the isle, > about 30" off the floor. I guess it should also rotate the PED > through all three axes, too. Sort of like a multi-dimensional version > of a CISPR 14 conducted emissions positioner. It should be in a > mode-stirred chamber to maximize envisions, right? > > BTW, I looked around the FAA website briefly to find something more > authoritive than a NY Times column, but didn't see anything. > > Pat > [email protected] > > On Sun, Mar 18, 2012 at 5:27 PM, Ken Javor <[email protected]> > wrote: >> Well, the author is either ignorant, or he has glossed over the realities. >> >> In turn: >> >> One cannot verify that a device won't cause interference by flying it on a >> single flight, or any reasonable number of flights. All of the possibly >> susceptible navigation and communication devices would need to be tuned to >> all the emitted signal frequencies to which these radios can be tuned. >> Further, the aircraft would need to be at the maximum required distance from >> the transmitting tower to ensure the SNR was worst case. >> >> The proper way to clear an aircraft for this sort of issue is a spectrum >> analyzer survey of the aircraft antennas. That way all the possible >> interfering signals can be collected at once, and the data can be analyzed >> as to whether there is a potential problem or not. >> >> BTW, this is WAAAY cheaper than a flight. And it's even cheaper than using a >> grounded airliner. An aircraft of the right type, but completely stripped >> and non-functional, is all that is necessary. The aircraft would need the >> appropriate antennas installed as in a flying aircraft, but that's it. >> >> But even given all that work, how do we know that all iPads (not picking on >> them, but just a name with which I'm familiar) are all the same? Do they >> all have exactly the same processors/RAM/what have you running at all the >> same frequencies? If a clock changes from one in which harmonics were >> out-of-band to a radio but now they are in-band, there could be a problem. >> Or if an IC has its internals modified, but is a form/fit /function drop-in >> equivalent, that can change the emission profile as well, and the device >> manufacturer wouldn't even know, because the IC manufacturer didn't change a >> part number. >> >> The fix here is EMI qualification testing of every variant that is sold, as >> longs as the manufacturer is aware of any and all changes to his internals. >> >> But even that isn't enough, because unlike regular aircraft avionics, these >> PEDs are not under the control of the airline. They have likely been >> dropped, immersed in or at least come in contact with liquids and the bottom >> line is that an initial qualification of one unit does not necessarily >> qualify all units sold over their usable lifetimes. One would have to look >> at the design to see what specific EMI reduction methods were used, and how >> they might be affected by ordinary misuse over a typical life. >> >> We have to remember here that while ordinary EN55022 type qualification >> protects the turf of licensed broadcasters, and thus their means of making a >> living, with the aircraft COMM and NAV systems, we are putting lives and >> property at risk. >> >> It would be one thing if the FAA wasn't allowing PEDs to be used at all. All >> they are doing is prohibiting their use during taxi, take-off and landing. >> >> Given the above issues, it makes much more sense for the flying public to >> remain unplugged for a few minutes at the beginning and end of every flight. >> >> This isn't asking a lot. >> >> >> Ken Javor >> Phone: (256) 650-5261 >> >> >>> From: Pat Lawler <[email protected]> >>> Date: Sun, 18 Mar 2012 16:54:01 -0700 >>> To: <[email protected]> >>> Subject: New immunity testing by the FAA in the future? >>> >>> Almost sounds like a whole new industry -- the business of testing >>> aircraft for immunity to personal electronic devices: >>> >>> http://bits.blogs.nytimes.com/2012/03/18/disruptions-time-to-review-f-a-a-po >>> li >>> cy-on-gadgets/ >>> >>> Pat Lawler >>> >>> - >>> ---------------------------------------------------------------- >>> This message is from the IEEE Product Safety Engineering Society emc-pstc >>> discussion list. To post a message to the list, send your e-mail to >>> <[email protected]> >>> >>> All emc-pstc postings are archived and searchable on the web at: >>> http://www.ieee-pses.org/emc-pstc.html >>> >>> Attachments are not permitted but the IEEE PSES Online Communities site at >>> http://product-compliance.oc.ieee.org/ can be used for graphics (in >>> well-used >>> formats), large files, etc. >>> >>> Website: http://www.ieee-pses.org/ >>> Instructions: http://listserv.ieee.org/request/user-guide.html >>> List rules: http://www.ieee-pses.org/listrules.html >>> >>> For help, send mail to the list administrators: >>> Scott Douglas <[email protected]> >>> Mike Cantwell <[email protected]> >>> >>> For policy questions, send mail to: >>> Jim Bacher: <[email protected]> >>> David Heald: <[email protected]> >> >> - >> ---------------------------------------------------------------- >> This message is from the IEEE Product Safety Engineering Society emc-pstc >> discussion list. To post a message to the list, send your e-mail to >> <[email protected]> >> >> All emc-pstc postings are archived and searchable on the web at: >> http://www.ieee-pses.org/emc-pstc.html >> >> Attachments are not permitted but the IEEE PSES Online Communities site at >> http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used >> formats), large files, etc. >> >> Website: http://www.ieee-pses.org/ >> Instructions: http://listserv.ieee.org/request/user-guide.html >> List rules: http://www.ieee-pses.org/listrules.html >> >> For help, send mail to the list administrators: >> Scott Douglas <[email protected]> >> Mike Cantwell <[email protected]> >> >> For policy questions, send mail to: >> Jim Bacher: <[email protected]> >> David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
