Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of corrosion on the horizontal stabilizer lower center skin panel, including a finding of corrosion where the skin thickness had been substantially reduced, which affected design margins. This AD requires inspecting the horizontal stabilizer lower center skin panel for corrosion, and reworking, repairing, or replacing the lower center skin panel if necessary. The FAA is issuing this AD to address the unsafe condition on these products.