Based on what the op has stated I would suggest that this is not a case of "criminalisation of air accident" rather it is a clear case of proecuting X because he deliberately falsified his ratings and committed an act of fraud.
There is no such thing as no jeopardy anywhere in the world. If you behave in a negligent manner your actions will have consequences.
Posecuting in the case of a genuine accident has no place in aviation however in this case X was not prosecuted for the accident but for his acts of fraud and misrepresentation.