Summary
This document proposes to supersede Airworthiness Directive (AD) 96-09-08 R1 applicable to certain Aviat Aircraft Inc. (Aviat) Models S-2A, S-2B, and S-2S airplanes, which currently requires repetitively inspecting the upper longerons just aft of the rear cabane struts for cracks and repairing any cracks found. The proposed action would retain the same actions as the current AD, lengthen the time interval between repetitive inspections, require either installing a marked accelerometer in order to continue to perform acrobatic maneuvers and installing a placard that specifies gravity (``g'') force limitations; or, installing a placard prohibiting acrobatic maneuvers; and, require inserting revisions into the Airplane Flight Manual (AFM). The proposed AD is prompted by reports of cracking in the upper longerons and the availability of an improved design modification that, when incorporated, reinforces the upper longeron area. The actions specified by the proposed AD are intended to prevent cracking and subsequent failure of the airframe, resulting in possible loss of control of the airplane.