AD FAA-2012-0673

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD requires inspecting parts or doing a records review to determine if certain trailing edge flap carriages are installed, doing repetitive inspections for corrosion, and flaking or missing thermal coating on suspect carriage spindles, and related investigative and corrective actions, if necessary; this AD also provides optional terminating action for the repetitive inspections. This AD was prompted by reports of corrosion found on carriage that are located on the outboard flaps. We are issuing this AD to detect and correct corrosion of the carriage spindle, which could result in a fracture; fracture of both the inboard and outboard carriage spindles, at the forward ends through the large diameters, on a single flap assembly, could adversely affect the continued safe flight and landing of the airplane.