Airworthiness Directives; Polskie Zaklady Lotnicze Spolka zo.o. Models PZL M18, PZL M18A, and PZL M18B Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to all Polskie Zaklady Lotnicze Spolka zo.o. (PZL-Mielac) Models PZL M18, PZL M18A, and PZL M18B airplanes. This AD requires you to repetitively inspect the centerwing-to-outboard wing attach joints for cracks in the lugs, corrosion in the main holes, and ovalization of the main holes; repair corrosion and apply anti-corrosion protection; replace the wing attach joints, as necessary; and eliminate any ovalization of the wing main joint holes. This AD is the result two instances of in-flight wing separation on Model PZL M18A airplanes where severe corrosion and pitting led to high stress concentrations on the wing attachment joints. The actions specified by this AD are intended to detect and correct cracks in the lugs, corrosion in the main holes, and ovalization of the main holes, in the centerwing-to- outboard wing attach joints. Such damage could result in failure of the joints with consequent in-flight wing separation.