Engines, I take your gentle differing in the spirit with which it is offered and certainly take the point that the personnel of the MilAAIB did as good a job as they could in the circumstances. It is those circumstances with which I take issue.
If the AAIB were a part of the CAA and there were airworthiness related accidents occurring one after the other in the civil air fleets because of systemic failures that rendered airworthiness provision dysfunctional under the CAA (the civil airworthiness authority), then the AAIB would be placed in the impossible position of finding Gross Negligence in its parent organisation. It wouldn't of course, because it is independent of the CAA for that very reason.
Here we have the whole incestuous relationship of UK Military Airworthiness Provision and Air Accident Investigation laid bare. The formation of the MAA has if anything worsened the situation that preceded Haddon Cave. There at least was the possibility that a well informed BoI President, prepared to go out on a limb in defiance of his superiors might just start asking the questions that I have suggested. The remote possibility of such a loose cannon has now been resolved by nesting the MilAAIB within the MAA, the very organisation that has inherited the Mare's Nest that is UK Military Airworthiness Provision. The VSO's can rest easy!
It is all very well for SI's to say, "not my job, mate!" when I suggest that they should delve deeper, but if they don't then they are part of the same problem that is the MAA, the Nimrod Report, and the MOD, ie the great cover up of the deliberate destruction of UK Military Airworthiness Provision. That is why 63 people died in the various airworthiness related air accident threads in the PPRuNe Military Forum. You'd think that would concern Air Accident Investigators, wouldn't you?