Airworthiness Directives; Textron Aviation Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Textron Aviation Inc. Models 401, 401A, 401B, 402, 402A, 402B, 402C, 411, 411A, 414, 414A 421, 421A, 421B, 421C, and 425 airplanes. This AD requires repetitively inspecting the left and the right forward lower carry through spar cap for cracks and replacing the carry through spar if cracks are found. This AD was prompted by a report of a fully cracked lower forward carry through spar cap found on an affected airplane. We are issuing this AD to address the unsafe condition on these products.