Engines - nail on head. If you pull the thread of thought regarding the seat safety case (or absence of) a little harder you will find a whole lot of people talking about how robust it was at the Mike Harland inquest. Yet a little while later we all found out that no such document actually existed, nor was one hastily crafted after Mike's death. They even got the RAF Chief Engineer to say how good MB were at managing the seat airworthiness.
No safety system, no lesson learned and then another death.