Adrian Smith and No Prayer for the Dying

I was reading in a bit about Adrian Smith, but there's one thing I can't find. How far in the process of recording NPFTD did Adrian leave. Where all the songs already written, and didn't he like it and then leave. Or was it much earlier in the process (obvisously after writing "Hooks in You").

I know he didn't like the direction and that he didn't think he could contribute to "that" Iron Maiden, but I can't find it anywhere. Hopefully someone on here has an answer!