Airworthiness Directives; Dornier Model 328-300 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Dornier Model 328-300 series airplanes, that requires, for certain airplanes, a one-time torque test (inspection) of the attachment bolts of the forward engine mount vibration isolators to determine if the bolts are adequately torqued, and corrective action, if necessary. For all airplanes, this amendment prohibits installation of an attachment bolt on the forward engine mount vibration isolators, unless the attachment bolt is torqued within certain limits. These actions are necessary to prevent failure of the engine mount, which could result in separation of the engine from the airplane. This action is intended to address the identified unsafe condition.