Always a Sapper
The answer is in Alfred the Great's earlier post....
In knowingly taken an article not on the RTS into the cockpit
One must be able to reconcile the Statement of Operating Intent and Usage, Aircraft Specification, Safety Case and RTS. In this case, you couldn't. According to previous reporting, it seems this subject came up in court, because he stated that it was known he took photographs, and some were on open display. Perhaps he concluded there was tacit approval; and it would seem nobody challenged him. After all, very few Aircraft Document Sets can be reconciled, and many RTSs are, frankly, nonsense. It works both ways. There is a duty to ensure the ADS is correct. At the risk of repeating myself, we have discussed many here that were not, including Chinook Mk2 and Sea King ASaC (the latter was a lazy copy of the old AEW Mk2, to such an extent it could be characterised as dangerous). There is an organisational fault here, and the pilot is the latest victim. He may have erred, but prior negligence occurred, only for the pilot to be hammered for the final act.