For those thinking about the role of the West Sussex Police, the AAIB and the local Coroner, it is worth reading what the judges actually said. The first quote relates to AAIB witness statements, the second to Coroners.
“In my view it is almost inconceivable that statements made to the AAIB could properly be the subject of an order for disclosure when the appropriate balancing exercise is done by this Court. This is for two main reasons.
First, there would be a serious and obvious "chilling effect" which would tend to deter people from answering questions by the AAIB with the candour which is necessary when accidents of this sort have to be investigated by it. This would seriously hamper future accident investigations and the protection of public safety by the learning of lessons which may help to prevent similar accidents. As is clear from the text cited earlier from Annex 13 to the Chicago Convention, the EU Regulation and the 1996 Regulations, this would be contrary to one of the fundamental purposes of the regime in this area, which is carefully designed to encourage candour in the investigation of air accidents in order to learn lessons and prevent accidents in the future.
Secondly, it would be unfair to require such disclosure. This is because the powers of the AAIB, unlike the ordinary police, are such as to permit the compulsion of answers to questions: see Regulation 9 of the 1996 Regulations. Further, so far as I could discern from the hearing before this Court, there is no clear practice, to say the least, of giving a caution to the person interviewed. This is hardly surprising, since the purpose of such an interview is to obtain the fullest possible information in an accident investigation. This contrasts markedly with the purpose of a police interview, which is to elicit evidence which may be capable of being used at a subsequent criminal trial.”
And:
“In the absence of credible evidence that the investigation into an accident is incomplete, flawed or deficient, a Coroner conducting an inquest into a death which occurred in an aircraft accident, should not consider it necessary to investigate again the matters covered or to be covered by the independent investigation of the AAIB. […] [T]he findings and conclusions should not be reopened.”
If you want to read the judgments in full you can find them here:
Sussex Police v Secretary of State for Transport & Anor [2016] EWHC 2280 (QB) (28 September 2016)
The Secretary of State, R (on the application of) v HM Senior Coroner for Norfolk & Anor [2016] EWHC 2279 (Admin) (28 September 2016)