Ahh, got it, thanks, Baz. It takes a civvie to ask a question like that. You'll all have to bear with me, I am learning, but not ashamed to ask. I'll look at the T.4 pilot's notes I have for the jettison switch - I only have a vague image of it my head but an inspection of it might make it clearer to me. And don't think for a second I am passing judgement here- just trying to understand the incident!