The FAA has proposed a new airworthiness directive (AD) requiring the inspection for metal fatigue of main wing spars on numerous Piper PA–28 and PA–32 single-engine airplanes that have reached a certain factored time-in-service level; reporting the inspection results to the FAA; and replacing wing spars that fail the inspection.
Source: aopaFAA proposes airworthiness directive on Piper wing spars