Summary
This document proposes to supersede Airworthiness Directive (AD) 98-08-22, which currently requires inspecting the elevator and rudder attachment brackets for cracks and corrosion, and replacing any cracked or corrosion-damaged parts on certain Pilatus Aircraft Ltd. (Pilatus) Model PC-7 airplanes. AD 98-08-22 resulted from mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. Since the issuance of AD 98-08-22, Pilatus has redesigned the brackets. Installation of these brackets should eliminate the cause of corrosion, which resulted in cracks or corrosion damage. The proposed AD would require you to replace the elevator and rudder attachment brackets with parts of improved design. The actions specified by the proposed AD are intended to prevent failure of the elevator and rudder attachment brackets because of cracks or corrosion damage. Such failure could result in the elevator or rudder separating from the airplane with consequent loss of airplane control.