Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Agusta S.p.A. Model A109C and A109K2 helicopters. This proposal would require removing the main rotor pitch link assemblies, measuring the radial play of the upper and lower spherical bearings (bearings), and replacing any unairworthy bearings. This proposal is prompted by four reports of increased vibration of the helicopters caused by wear in the bearings of the main rotor pitch change link assembly. The actions specified by the proposed AD are intended to detect unairworthy bearings on the pitch change link assembly and to prevent increased vibration and subsequent reduced controllability of the helicopter.