Duress

[Jean-Francois Avon JFA Technologies, QC, Canada]

The transponder analogy might not be very accurate.

When you fly in a controled airspace, the *controller* asks you to 
dial in certain digits on the transponder.

If you do not dial them in, the controller will start harrassing you
for doing it and for not complying and for entering airspace
while unauthorized.

You have to do it.  depending on cockpit configuration, the hijacker
might very well have no choice but to let the pilot do it.

In any case, this is a situation where there are 3 persons involved
(hijacker, pilot and controller) vs 2 in the duress case

I would guess that most hijacks gets disclosed before they land because
there are so many ways that the pilot could stego a help message in the
flow of the numbers that are exchanged btwn him and the ground.

JFA
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