Airworthiness Directives; Dornier Model 328-100 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Dornier Model 328-100 series airplanes, that requires replacement of the existing pressure dump and relief valves in the main and auxiliary hydraulic systems with new valves. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of the pressure dump and relief valves in the main and auxiliary hydraulic systems, which could cause a loss in hydraulic pressure for roll control spoilers and brakes, and consequent reduced controllability of the airplane.