Summary
We propose to supersede an existing airworthiness directive (AD) that applies to certain Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. The existing AD currently requires revising the airworthiness limitations section (AWL) of the instructions for continued airworthiness (ICA) of the Canadair Regional Jet Maintenance Requirements Manual by incorporating new procedures for repetitive detailed and special detailed inspections for cracking of the aft pressure bulkhead. Since we issued that AD, we have received multiple reports of cracks on the forward face of the rear pressure bulkhead (RPB) web. This proposed AD would require 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. We are proposing this AD to detect and correct cracking in the RPB, which could result in reduced structural integrity and rapid decompression of the airplane.