Airworthiness Directives; Pilatus Aircraft Ltd. Model PC-7 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain Pilatus Aircraft Ltd. Model PC-7 airplanes. This AD requires replacing the seal unit on both main landing gear (MLG) legs and the nose landing gear (NLG) leg. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this AD are intended to prevent MLG or NLG failure caused by deterioration of a MLG or NLG leg seal unit, which could result in damage to the airplane or airplane control problems during takeoff, landing, or taxi operations.