Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are superseding Airworthiness Directive (AD) 96-12-12, which applies to certain Piper Aircraft, Inc. Models PA-31, PA-31-300, PA-31-325, and PA-31-350 airplanes. AD 96-12-12 requires a one-time inspection of the bulkhead assembly at fuselage station (FS) 317.75 for cracks and the installation of one of two reinforcement kits determined by whether cracks were found during the inspection. This new AD requires repetitive inspections of the bulkhead assembly at FS 317.75 for cracks, repair of cracks as necessary, and the installation of a reinforcement modification. This AD was prompted by cracks found in the FS 317.75 upper bulkhead. We are issuing this AD to correct the unsafe condition on these products.