Posted for "John Schroeder" <jschroeder@perigee.net>:

 Colyn -
 
 The RMI/EMI is coming in through either the power wiring, signal wiring from
the flap sensor or the trim actuators or directly to the circuitry in the
indicator itself. It is not a good avionics design. It should have complied
with the standards in DO 160 (?). There are cures, but not worth the effort,
unless you want to swap them out for something else.
 
 John