AD FAA-2013-0301

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 767-200, -300, -300F, and -400ER series airplanes. This AD was prompted by reports of cracked and corroded nuts on an outboard flap support rib. This AD requires, for certain airplanes, repetitive inspections of the cap seal for damaged sealant on nuts common to certain outboard flap support ribs, and related investigative and corrective actions if necessary. For certain other airplanes, this AD also requires repetitive inspections of the cap seal for damaged sealant on nuts common to certain outboard flap support ribs, related investigative and corrective actions if necessary, and if necessary, a detailed inspection to determine the nut type installed in the outboard flap support rib and corrective actions. This AD also provides terminating action for the repetitive inspections under certain conditions. We are issuing this AD to detect and correct cracked and corroded nuts and bolts and the installation of incorrect nuts on certain outboard flap support ribs, which could lead to additional nut and bolt damage in the joint, result in loss of an outboard flap, and adversely affect continued safe flight and landing of the airplane.