Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Dornier Model 328-100 series airplanes. This proposal would require replacement of the existing pressure dump and relief valves in the main and auxiliary hydraulic systems with new valves. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed 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.