Like I said, I doubt it will be in the FBI file unless it started out as assaulting a police officer or something serious and then got reduced.

As far as other records, it's just a crapshoot on what kind of check they run and how well the local records system in question is maintained (often not very well). The most reliable background is to pull county records from all the places you have lived, but that can be expensive. Some majors will probably do that, but few regionals.

If you are honest about it, I suppose the impact will be affected by the back story. Were just walking home minding your own business and they grabbed you? If you can prove that (police report, court docs) it might not be a big deal. But like I said before...there is usually some egregious behavior leading up to that.

Depending on the details of the situation, my guess is that you could get hired by a bottom feeder regional, maybe even a better regional if you completed some kind of HIMS program. Did they FAA medical make you do anything like HIMS or eval?