Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of difficulties in opening the airstair door. This AD requires inspecting the structure and gearbox drain paths for blockages by sealant, and removing any blockages. We are issuing this AD to detect and correct drain paths blocked by sealant, resulting in an airstair door that is unable to be opened, which could hinder evacuation in the event of an emergency.