As stated, if they tell you business casual you are ok to wear it. If they are flying down for the logbook review, they pretty much have made up their mind about you.

The CP literally tells you to relax, this isn’t an interview or test. They just want to see your books, have a quick chat and give you the offer. This was all my experience at least.

At the end of the day however, I don’t think anyone would fault you for wearing a suit.