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> If the "compass var." setting on the instrument (or in French, "deviation
> compas") is at zero degrees (as is originally preset when you take it new
> out of its box), then as you would expect, the magnetic course to that
> waypoint is zero degrees.
>
> Now if you change "compass var." to 10W (the sign is set as E or W, not +
> or -) the indicated compass course to the North pole waypoint becomes
> 350deg, not 10 deg as it should be. The only way to obtain the correct
> magnetic course that you need (010 deg.) is to take the variation given on
> a chart (say 10 deg West) and enter it as "10E".
>
> There's no need to go into what you add or subtract from what to get what.
> The behaviour is clearly WRONG. There is a serious blunder in the
> programming of that instrument, which will result in magnetic courses in
> error by twice the variation. As far as I can tell, the makers are
> attempting to deny the blunder (as I have found out in discussion with
> their distributor). I have emailed M.  L. Moreau at
> lmoreau@thalesnavigation.com and await his reply.
>
> The manual is completely silent on this matter, except for the following
> words-
> "BRG = Bearing from your position to the position of the destination
> waypoint, in degrees. This bearing relates to true North but an off-set to
> compensate for local compass variation may be entered if required."
>
> Taken with the label "compass var.", would the user expect to enter
> against
> that label the compass variation from the chart, or a variation in the
> opposite sense?

I think whoever did that programming thought of the "variation to get to the
compass heading" instead of "variation *of* the compass heading." As you
say, clearly wrong and misleading.

YA

   

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