Hi, Derek (and group).
Many of us have over a long career had the chance to work on aircraft
systems (or others) for which immunity standards are imposed. In most
cases the signals emitted from properly functioning,
non-intentional-emitter PED do not ever reach the levels the subject
equipment is required to tolerate. IMO, it is in those cases still not
proper to say PED operation should be permitted during flight regimes.
There remain sensitive spectra be investigated; VHF communications, VHF
and UHF navigation and landing systems, IFF, DME/TACAN and TCAS systems
and the like. There have actually been ASRS reports of PED's affecting
flight situation indicators and ILS flags, so for such victim devices,
it seems we do need to test to levels of emissions and likely at levels
lower than those permitted normally.
Intentional emitters are quite another matter -- see ED-118 re threat
levels -- and systems that react to them may never have been tested
against the particular threat one may pose. While DO-160 threat levels
are higher than most of the PED's a person might bring aboard, most of
the tests use a nominal modulation only ASSUMED suitable for the
purpose. I am now thinking about the famous case of a GSM telephone
which, being under 30 cm from a victim (oven controller) device, turned
on a gas broiler and almost caused a fire. It does not help that those
who make and sell aircraft systems have a great deal of incentive to do
only the minimum required testing, and a good deal of disincentive to
spend time going beyond that. We simply have not tested against all
threats a passenger might carry, and this is another thing missing from
our analyses.
Some years ago I had occasion to test an automatic external
defibrillator for emissions in the aircraft VHF and UHF comm, navigation
and landing frequencies, IFF, TACAN/DME and TCAS ranges. It appeared
at the time that none of the personnel at the firm I was then on
contract to (or at the test labs being used) had ever done such a test.
But it is OUR business to know the test is needed -- and if possible,
see it gets done. I was writing the verification plan and was able to do so.
Cortland Richmond
On 3/24/2012 1356, Derek Walton wrote:
HI All,
I've watched may people speculate about PED's and what they MAY do, so
I decided to go in the lab and make some measurements on my new iPad.
Obviously conducted is not an option, there's no power cord.
For radiated emissions to 1 GHz, the device is as quiet as a mouse. It
was only a quick look see, so I set it up as if I were reading a book:
I have no movies loaded yet.
Clearly there are other options, so if any one would like to chip in
as to the way it should be running when tested let me know and I'll
run when I get a second and post results.
I'm thinking either playing a game with lots of video or a High
resolution movie.
Passive headset inserted also, cord unbundled.
Anything else?
Cheers,
Derek.
L F Research
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