Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to certain Pilatus Aircraft Ltd. Model PC-7 airplanes. The proposed AD would require replacing the seal unit on both main landing gear (MLG) legs and the nose landing gear (NLG) leg. The proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by the proposed 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 controllability problems during takeoff, landing, or taxi operations.