PPRuNe Forums - View Single Post - A320 HDG to NAV “wiggle”
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Old 28th Dec 2017, 20:58
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Below the glide
 
Join Date: Aug 2015
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Originally Posted by CaptainMongo
Pardon me, but I am not satisfied with the responses.

I am proceeding direct to waypoint ABC which is 300 NM in front of me. I decide to create a new waypoint which will be ABC -100NM. I open the FIX INFO page. I type in ABC and 100 in radius. I select 4L which drops the radius into FPLN. That radius fix remains dynamic until I select heading.(does it not?) I select heading, insert, then select NAV. I can do that in one second, yet I still get a wiggle.
What’s the FMS standard firstly? What’s the ADIRU standard for magnetic variation?

These always a mismatch of a Nav database geometric convention versus a calculated or assumed point on space. Older FMS standards have these specifics. Perhaps take a look at the FCOM in system related (21 or 34) for these anomalies
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