If I was unsure of the exact ATA chapter and verse to add to the paperwork then I would say that the hydrolock was adjusted IAW chapter 25.(Its gotta be in there somewhere). I also find that chap 20 is also a good one to quote when you aint got a clue where to look. It gets up the QA jobsworths noses but i'm sure we all have broad enough shoulders to take a little flack. Take a look at the joke about the Caa interview in the humour on this site, It could apply to QA aswell.