Place your close-out panel on top of your sump drain access panel and below your header tank as shown in the photo to the right. Drill with a 3/16" bit in two places as shown in the left photo. Add clecos as you drill to prevent shifting.
Remove rivet head on side of aircraft body (as shown in left photo below) and drill through into the header tank close out panel using a 3/16" drill bit.
Remove close-out panel from aircraft. Using an anchor nut as a guide, drill two #40 holes beside the holes you just drilled. Then install the anchor nuts using the rivets provided.
Next, using the screws provided, screw the panel onto the aircraft.
Again, install this screw through the side of the aircraft body as shown in the photo on the right.
Note: The photos above show the panels out of the aircraft, this is only for demonstration purposes. Please install your sump drain access panel first, then install the close-out panel second.