You also drill thru the skin the screw holes with #19 drill.
Then you buy a piece of 3/4 X 3/4 aluminum angle and cut a piece about inches long. This locates along the rib and attaches the side of the pitot bracket.
You drill the angle using holes in bottom skin and bracket as guide.
Then you can drill a big hole in the middle and I used my dibbler to start making the hole for the pitot tube bracket shaft.
