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If I change the tail number of an aircraft within X-Plane by modifying sim/aircraft/view/acf_tailnum (either with LUA script or with the DataRefEditor) I would expect X-Plane to use this new tail number in ATC clearances or for writing to the logbook.
However, this does not happen (at least not in XP11).
Why is the DataRef writable if it does not have any visible effect?
The question was not about visual representation but the usage of ATC messages that could use the current value in sim/aircraft/view/acf_tailnum .
That dataref is writeable - for flight plan related management it would be better if X-Plane atc uses that, rather than anything hardcoded in the acf on load of plan.
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