Barbie,
Beagle has succinctly answered your question! But I will add to it because it is a very grey area - even AP3207 at the time was not totally clear.
If they intentionally flew into the hill or cloud (knowing that particular bit was culmulo-granite) - the cause group would have been Human Factors (Aircrew) (Gross Negligence) - recklessness, disobedience or effectively suicide and/or murder. Unlikely, but we can't prove it.
If they unintentionally flew into the hill/culmulo-granite then it would have been either HF(A) (Negligence) or (Error of Judgement). Which one would depend on how the BoI and ROs assessed any of the mitigating circumstances. As we know, the latter were rather less charitable than the former. The latter decided to ignore the fact the crew could not climb to above the appropriate Safety Alt (approx 6500ft) because of the icing limit, instead insisting that the ac could climb to about 2500ft to miss the Mull - absolute poppycock - that would put the ac 'IMC below SAlt' - such a suggestion would be incredibly poor airmanship! The former elected to discount the parts of the AAIB report that indicated various control problems and distractions 'could not be positively discounted' and then forgot that 'no evidence of failure does not mean there was evidence of no failure'!
Also, both parties used flawed simulations and incomplete assessments of equipment as ADR-type 'evidence' to come up with a postulation that all Chinook pilots to whom I have talked describe as rediculous (ie the 'inappropriate ROC' over the Mull). The mitigating evidence that the aircraft had no navigational clearances of any worth at all was not discovered bythe BoI, nor did the BoI discover that the higher authorities (ACAS and Controller Aircraft) had by-passed the process of airworthiness and had ignored expert pleadings that the aircraft was 'positively dangerous'. Day and Wratten would have been accutely aware of the problems as they were understandably very keen to get the HC2 up and running. But by written definition of the regulations, the aircraft was too 'immature' for release and not fit for the purpose of a pax transit sortie. Even if no technical fault occurred that afternoon, this in itself, adds up to a considerable measure of mitigation and the cause group drops to HF(A) (Error of Judgement) at the very least but because the AAIB report mentions the lack of evidence on the ground and because there was only one eye-witness to the in-flight weather, I believe that 'Not Positively Determined' (NPD) would be appropriate .
The lack of a CVR/ADR and having no true assessment of the in-flight weather conditions limits the amount of factual evidence, thereby creating a modicum of doubt in anyone with an open mind. Therefore, the ROs ignored the regulation that dead crews cannot be accused of negligence, unless there is absolutely no doubt whatsoever. Some people believe that it would be impossible to ever overcome this 'obstacle' in allocating blame. When I asked the Air Officer who added this rule in the 1980s, he said that this was the intention - as the dead cannot speak for themselves and have no right of redress! The ROs may have truly believed their assessment but they cannot prove it - and certainly with absolutely no doubt whatsoever!
Therefore, a reassessment of the evidence can only point to a cause of either 'Not Positively Determined' (NPD) or 'HF(A) (Error of Judgement)' - neither of which allocates blame as negligence would.
Importantly, however, one would also have to include 'Organisational Fault' (O) and 'Unsatisfactory Equipment' (UE). Although not part of the BoI, it is also possible that ACAS and Controller Aircraft and their staffs would have been subsequently Court Martialled for negligence in their duties - sadly unlikely!
If, however, the aircraft had had a FADEC fault leading to temporary/intermittent Run-Away Up/Down or spurious engine failure or a control restriction or AFCS fault, then this would not have been in 'Controlled Flight' and so the cause group would have been Technical Fault (TF). In this case, it would also have been O and UE with the ensuing Courts Martial. Because of the paucity of evidence this cannot not be proven but neither can it be discounted.
In sum, the lack of a CVR/ADR and the overall paucity of factual evidence must create an element of doubt - as evidenced by the numerous opinions on this thread. Unfortunately, an opinion does not amount to the evidence to decide with 'absolutely no doubt whatsoever'. This scarcity of factual evidence would indicate that perhaps the most appropriate cause group is NPD.
So, to answer your question Barbie, the cause group is somewhere on the scale from O & UE, through HF(A) (Error of Judgement) to NPD or even a combination of all 3 but not, I believe, negligence. Take your pick.
Ultimately, I think O & UE is definitely a major contributory factor. It also puts the Air Staffs' inactions in the category of negligence and on a date before the the accident . In doing so, this creates definite mitigating circumstance for the crew. Unfortunately, we will never, ever know what actually happened the day of the accident, so NPD gets my nod for the final cause group.
Hope that helps
flipster
Last edited by flipster; 13th Feb 2010 at 08:58.