Keep in mind that there is a difference between "valid" and "correct".

For example, a computer program may require that a number be entered in a
specific field.

Any number that is entered would be "valid", but it would not necessarily be
"correct".

A given electronic device might cause a reading to be 10 degrees off. The
nav system might well interpret the data as "valid" even though it would not
be correct.





"Marco Leon" wrote in message
oups.com...
Saw a repeat episode of Mythbusters for the first time last night about
the use of cell phones on an airplane and interference with cockpit
instruments. I know that this was mentioned in a November 2006 thread
briefly but the short of it was that they concluded cell phones really
CAN interfere with the VOR signals.

One of the tests however, was on a Hawker jet with a glass cockpit
(Honeywell I believe) with a FMS. They could not get any frequencies or
amplitude of cellphone signals to budge the instruments like they were
able to on a 1970's era NAV system. From what I understand, the FMS
relies on a number of different inputs to drive its nav systems. If
that's the case, wouldn't it switch to another source if one seemed
unreliable? If it does, I imagine it would be a fundamental flaw in
their experiment. The FBO manager and avionics guy being interviewed
however, gave the nod to the robust wire shielding.

Marco