GPS interference testing

wrote:

Seems clear that tampering can be managed from outside the unit while
producing secure, valid record files. I've been amused, for instance,
that the OLC will highlight a flight if it is downloaded improperly

This is a problem.
or transfered among media prior to uploading,

Transferring among media is not a problem. The file and it's signature
are preserved when the file is copied between hard drives, memory cards,
floppy disks, sent by email, or via the web. Consider: I download my 302
file to my Ipaq memory card, the file is transferred via Activesynch
(desktop) or memory card reader (laptop) to a computer hard drive, then
uploaded to the OLC.

but otherwise assume all is well.

There is a procedure for disputing flight claims, but the OLC does not
routinely attempt to verify flights. Quite reasonable, considering the
goal of the OLC.

It's tough to thwart a determined cheater. But since the vast majority
of cheating is a matter more of convenience than maliceaforethought, to
most of us the emphasis on security seems draconian. Now that we have
clear evidence that there are external devices that can spoof our
recorders,

This isn't news, but has been discussed here and elsewhere for years.

is it the next step to require that recorders have some
protection against such possibilities? Or is this where we throw up our
hands and say "enough" and put the responsibility back into the hands
of the observer?

I think we did this quite a while ago. It's always been known that the
recorders don't offer protection against external signals, either
intentional or unintentional.

--
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Eric Greenwell
Washington State
USA