Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8 series airplanes. This proposal would require a one-time inspection of the spring assemblies located in the rudder control feel unit to verify that dual rate configuration springs are installed; and revising the Airplane Flight Manual to prohibit airplane operation from runways less than 75 feet wide, if necessary. This proposal also would require eventual replacement of any single rate configuration springs with dual rate configuration springs, which would terminate the requirement for the AFM revision. 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 an asymmetric rudder force condition, which could result in reduced controllability of the airplane and consequent potential for center line deviation.