Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to all Cessna Aircraft Company (Cessna) 180, 182, and 185 series airplanes equipped with wing extension supplemental type certificate (STC) SA00276NY. The proposed action would require inspecting between wing station (W.S.) 90 and W.S. 110 for an angle stiffener at the lower wing spar splice. If the angle stiffener is not installed, the proposed action would require installing a reinforcing strap. The proposed action is the result of failed test results revealing that the wings of these Cessna airplanes, without the stiffener, do not meet the applicable design requirements after being modified by the above STC. The actions specified by the proposed AD are intended to prevent wing failure during flight, which, if not corrected, could cause loss of control of the airplane.