Originally Posted by
DaveReidUK
Interestingly the NTSB (though not the AAIB) demarcates its analysis of findings after an accident into 3 categories:
Probable Cause/s
Contributory Factor/s
Other Factor/s
While that last category might appear to be a contradiction in terms (a factor that didn't contribute to the event/outcome), it's a useful repository for findings such as the state of the Hunter's fuel pump diaphragm.
Indeed, and an observation made many times about AAIB reports, which are often difficult to read. Case in point.
MoD Service Inquiries are structured like this (Causal, Contributing, Aggravating and Other Factors, and Observations). Importantly, the rules state that ALL must be addressed. They seldom are.
In the vast majority of cases the Factors and Observations are recurring and, as stated by Pobjoy, the Recommendations amount to 'implement mandated policy'. Here, that failure is a Causal Factor, as the aircraft shouldn't have been flying. ('Failure' is kind. It was flat refusal and more deserving of a gross negligence manslaughter charge than the pilot).
If one can be certain the fuel pump (in this case) did not contribute, then by all means put it in 'Other Factors'. But, actually, it is but one of many pointers to the greater failings - refusal to maintain airworthiness and failure of independent oversight. It could be said this is also a Casual Factor. Authorities usually argue against this, but only because their default starting point is that airworthiness has always been maintained. They would be better assuming it is never maintained. Here it was not, and the CAA knew it, so the fuel pump violation simply becomes supporting evidence to a Causal Factor.