Gradually upsized upper hole for left tank attach bracket. Cobbled #12 drill bit broke off in hole. Interior access to hole was difficult; tried to tap bit out from inside cockpit. Big mistake. Access unworkable, and bent interior floor panels in the process because they weren't secured by clecos in some areas. Had to remove flap actuation assembly and all floor panels. Managed to straighten out panels into decent shape. Kneeled on wing walk area to tap out broken drill bit. Ordered replacement bits from Cleaveland Tool.
