Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional Jet Series 100) Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 and 200) series airplanes, that currently requires repetitive inspections to detect cracks of a certain bulkhead web of the fuselage at certain locations, and repair, if necessary. This amendment revises the repetitive inspection intervals for certain airplanes, and requires modification or repair, as applicable. This amendment is prompted by the development of a modification that will adequately address the identified unsafe condition. The actions specified by this AD are intended to detect and correct fatigue cracking, which could result in uncontrolled depressurization of the airplane and/or reduced structural integrity of the fuselage.