

Are they really required to obey?
I was under the impression that as PIC you can tell ATC that you are unable to follow instructions but you better be able to back it up later (ie. Flying VFR and ATC tells you to fly into a cloud). Following TCAS over ATC is definitely defensible unlike the famous 1NR. I don’t know if it’s required but it certainly seems like a good idea
Edit: I skimmed the AC from 1993 wrt TCAS:
https://www.faa.gov/documentLibrary/media/Advisory_Circular/ac120-55A.pdf
Again I skimmed not read so don’t take my next statement as proof of anything, especially if you will operate as PIC:
Generally speaking, follow TCAS unless doing so would be more dangerous
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