this has been driving me insane for two weeks. had a pretty mild crash honestly, just clipped a tree branch at maybe half throttle and came down into grass. nothing looked broken, replaced the props just in case and went back out and now theres this vibration showing up in the blackbox logs that was not there before. gyro traces look noisy above certain throttle ranges, its not consistent, seems worse in certain orientations.

ive balanced the props, checked all four motors by hand and they all feel smooth, tightened every standoff and screw i could find. filters are the same as before the crash. i'm kind of at a loss here. my mate suggested maybe the FC mount got tweaked somehow and its picking up more frame resonance now but i cant see anything obviously wrong with it.

anyone dealt with something like this where the actual source ends up being something stupid you wouldnt have thought to check

check your motor screws, not just snug but actually check every single one with a driver. a loose motor screw is almost invisible to the eye but will absolutely trash your gyro traces and it's one of those things where you crash, think everything is fine, and one screw is just barely not seated right. i've been burned by this twice.

also if your FC is on a soft mount check that the grommets didn't get compressed or shifted in the impact. sometimes a grommet cracks internally and you can't see it but it changes the isolation properties completely. might be worth just replacing all four grommets as a baseline, they're cheap.

honestly could also be a prop that looks fine but isnt balanced right, i know you said you balanced them but did you use a proper balancer or just eyeball it? i thought i was being careful once and turns out one blade was like visibly thicker than the other and it was causing all kinds of grief in the logs. also ? what frame is it, some of them have known resonance points at specific throttle percentages and the filters need to be tuned around that separately, unrelated to your crash but could be making whatever minor issue worse.