Airworthiness Directives; Bombardier, Inc. Airplanes

We propose to supersede Airworthiness Directive (AD) 2012-25- 02, which applies to certain Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. AD 2012-25-02 requires revising the airworthiness limitations section (AWL) of the instructions for continued airworthiness (ICA) of the maintenance requirements manual by incorporating new procedures for repetitive inspections for cracking of the rear pressure bulkhead (RPB). AD 2012- 25-02 also requires revising the maintenance program to incorporate a revised task which requires an improved non-destructive inspection procedure. Since we issued AD 2012-25-02, additional in-service crack findings resulted in the development of a structural modification to the RPB. This proposed AD would mandate modification of the RPB and would add repetitive inspections for cracking of the RPB web, which would terminate certain actions in this proposed AD. We are proposing this AD to address the unsafe condition on these products.