leo238•4d ago

Can we talk about the 0.040 inch minimum on a King Air brake disc rivet?

I was going through a set of brake assemblies on a King Air 200 two weeks ago and pulled the maintenance manual just to double check the rivet setback before I started drilling. The number in the book was 0.040 inches minimum between the rivet head and the lining edge, and I had been eyeballing it at closer to 0.030 for years without ever getting called on it. My old lead at a shop in Tulsa told me years back that if it felt snug it was fine, so I never went back to verify it. I started measuring every disc with a set of calipers after that, and three of the six assemblies I did that week were under spec. I am not saying we were flying unsafe planes, but it was closer than I want to admit. Does anyone else have a spec like that they only learned by actually reading the book cover to cover?