Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-400, -401, and -402 airplanes. This proposal would require a one-time inspection of the forward engine mount assemblies on the left and right engine nacelles for installation of pre-production engine mount assemblies, and follow-on corrective actions if necessary. This action is necessary to prevent failure of the forward engine mount, which could result in reduced structural integrity of the nacelle and engine support structure. This action is intended to address the identified unsafe condition.