> Every NTSB report has a "probable cause" section determining who or what was at fault. And then the FAA hands out fines and courts award additional damages largely based on that finding.

In case everyone is not aware, NTSB reports cannot be used in court to establish fault or otherwise be used as evidence when seeking compensation for damages.

"No part of a report of the Board, related to an accident or an investigation of an accident, may be admitted into evidence or used in a civil action for damages resulting from a matter mentioned in the report." 49 USC 1154(b)

I have a question..

In criminal cases what happens with inadmissible evidence? Like fruit of poisonous tree doctrine... what if you literally have video proof and tons of other graphic proof of a murder, you really just ignore it and let the perp go back into society?

There are exceptions to the doctrine for exactly the reasons you mention. The legal system isn't as insane as people like to make it out to be.

if you have tons of proof about a murder, it's almost certain to fall under one of the exceptions to the doctrine. e.g, if law enforcement would have discovered the evidence anyway, it is not excluded.

In principle, it’s inadmissible. So, theoretically, yes. The perp just goes free. Not very common for a lot of reasons.

The part you missed is probably the post mortem investigations are why air travel is the safest form of transportation.