Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding an existing airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. That AD currently requires revising the airworthiness limitations section (AWL) of the Instructions for Continued Airworthiness (ICA) of the Canadair Regional Jet Maintenance Requirements Manual (MRM) by incorporating new procedures for repetitive detailed and special detailed inspections for cracking of the aft pressure bulkhead. This new AD requires revising the maintenance program to incorporate a revised task specified in a certain temporary revision, which requires an improved non-destructive inspection procedure; and adds airplanes to the applicability. This AD was prompted by multiple reports of cracks on the forward face of the rear pressure bulkhead (RPB) web. We are issuing this AD to detect and correct cracking in the RPB, which could result in reduced structural integrity and rapid decompression of the airplane.