AD FAA-2012-0592

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 a one-time inspection of the shafts of the main landing gear (MLG) side-brace fittings to detect corrosion, and the forward and aft bushings in the left-hand and right- hand MLG side-brace fittings to detect discrepancies. The existing AD also requires corrective and related actions if necessary. This new AD requires repetitive detailed inspections for corrosion and damage of the MLG side-brace fitting, and replacing the side-brace fitting shaft with the re-designed side-brace fitting shaft of the MLG if necessary. This AD also requires eventual replacement of certain side-brace fitting shafts with the re-designed part. Replacement with a re- designed side-brace fitting shaft of the MLG is terminating action for the repetitive inspections. This AD was prompted by reports of failure of the side-brace fitting shaft of the main landing gear (MLG) due to corrosion. We are issuing this AD to prevent fractures of the side- brace fitting shafts of the MLG, and possible collapse of the MLG.