Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We propose to adopt a new airworthiness directive (AD) for certain Piper Aircraft, Inc. Models PA-31, PA-31-300, PA-31-325, and PA-31-350 airplanes. This proposed AD was prompted by fatigue cracking in the fuselage station (FS) 332.00 bulkhead common to the horizontal stabilizer front spar attachment. This proposed AD would require repetitive inspections to detect cracks in the bulkhead and any necessary repairs. This proposed AD also provides an optional modification if no cracks are found that will greatly reduce the likelihood of the specified cracks. We are issuing this proposed AD to correct the unsafe condition on these products.