Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This proposal would require repetitive inspections of the check valves and air supply ducts of the rear bulkhead for damage, and related corrective actions. This proposal also would require eventual rework or replacement of the air supply ducts, which would terminate the repetitive inspections for the air supply ducts only. This action is necessary to prevent disconnection of an air supply duct, which, if combined with failure of a bulkhead check valve, could result in rapid depressurization of the airplane. This action is intended to address the identified unsafe condition.