Yeah, I will definitely keep everyone posted on the outcome. In case it wasn't clear, I was doing a solo flight so instructor was not with. I know that doesn't exempt him from all of this, just wanted that to be clear.
Since no one has clarified, I'll throw this out there... when you're a student, to the FAA you're always flying under the supervision of an instructor. That solo endorsement says the instructor trained you for solo flight and signed on the dotted line that you're okay to be in whatever controlled or uncontrolled airspace you're signed off to fly in. That's the connection to the instructor in the FAA's eyes. They understand the instructor wasn't on board, but they still have to investigate to make sure the instructor hasn't gone rogue and is signing people off for things they didn't teach correctly.
Your instructor will be fine, students make mistakes. It's just a matter of knowing solo student flight is legally "flying on the instructor's ticket" and FAA double checking that the instructor taught the right things and also can come up with a plan to remediate and teach any mistakes that happen. Then it just kinda goes into the "unknown" from there, and depends a lot on the student and instructor's attitudes and the inspector. The vast majority treat it as a team effort to figure out what went wrong and fix it.
As you can see from the thread, "stuff happens" to a lot of people. Almost everyone who's been flying long enough has a serious mistake or two under their belts.
Note
@midlifeflyer 's words carefully, he's probably the closest thing to an expert on the legal side of things as we have here. FAA has a lot of leeway in the specific actions they can take, and he listed some or all of them. They can take those actions against you or the instructor, and an awful lot of what they choose to do depends on everyone's attitudes.
The other good news about "automatic" enforcement actions from controllers, if there is any, is that the inspectors have a lot of cases to work. If you and your instructor are "already on it", fixing the issue and doing remedial training, versus some doofus they're also working a case on that week who "doesn't get it" and isn't repentant and humble about their mistake, guess who's getting the fire rained down on them while the instructor and student who made an honest mistake and are working to correct and gets a letter of reprimand (or similar) and their remedial training plan "approved" by the inspector so the inspector can move on to worse problem children?
You just don't know what kind of day/week/month the inspector is having. Being humble and polite and non-confrontational while still aware that the mistake was serious, can go a long way.
Instructors CAN get calls from FAA *years* after training, when things go horribly wrong. "Yes, we trained on that thing. I follow a syllabus and that is covered, and that student didn't have any indications during training that they would not do it." Etc. That's just how it goes for instructors.
And students can call up years later asking for advice in a Pilot Deviation, too... their instructors might be the only people they know who've had any regular contact with FAA and might know the inspector and their style. Or sometimes a former student just may feel the only place they can find advice about something is from the people who taught them.
I've seen instructors "go to bat" for good pilots years after they taught them when something "stupid" happens and a former student is in some sort of trouble. Aviation is a small world.
Good people help good people, and there's a couple of cases I know of where instructor friends of mine are helping or have helped former students with possible enforcement cases because they know the former student isn't a twit and isn't reckless, and they want them to succeed in the biz. Since one is ongoing I can't/won't share details, plus I'm a third party and wouldn't have them 100% right anyway. Point is, their old instructors are vouching for them in front of FAA.
I suspect your instructor will too. We all know students are our responsibility in many ways, and certainly legally, while they're flying on our tickets. Your instructor wasn't there to say, "Stop! Go around!" but they want to instill that voice in your head so you'll hear it the next time something isn't quite right...
