Airworthiness Directives; Cessna Aircraft Company (Cessna) Models 336, 337, 337A (USAF 02B), 337B, M337B (USAF 02A), T337B, 337C, T337C, 337D, T337D, 337E, T337E, 337F, T337F, 337G, T337G, 337H, P337H, T337H, T337H-SP, F337E, FT337E, F337F, FT337F, F337G, FT337GP, F337H, and FT337HP Airplanes

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires inspecting the wings for internal and external damage, repairing any damage found, installing an operational limitation placard in the cockpit, adding limitations to the flight manual supplement, and reporting the results of the inspection to the FAA if damage is found. This AD was prompted by a wing overload failure and by reports of cracks in the upper wing skins on certain Cessna airplanes that are or have ever been modified by Aviation Enterprises Supplemental Type Certificate (STC) SA02055AT, SA02056AT, SA02307AT, or SA02308AT. We are issuing this AD to detect and correct damage in the wings and to prevent overload failure of the wing due to the installation of the STCs. Damage in the wing or overload failure of the wing could result in structural failure of the wing, which could result in loss of control.