AD 97-26-20 62 FR 67708

This amendment supersedes Airworthiness Directive AD 96-09-08 R1, which applies to Aviat Aircraft Inc. (Aviat) Models S-2A, S-2B, and S-2S airplanes (formerly Pitts Models S-2A, S-2B, and S-2S), and currently requires repetitively inspecting the upper longerons just aft of the rear cabane struts for cracks and repairing any cracks. This action retains the same actions as the current AD; lengthens the time interval between repetitive inspections; requires 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, requires inserting revisions into the Airplane Flight Manual (AFM). This action is the result of reports of cracking in the upper longerons caused by operating the airplane outside of the certificated design limits and the availability of a design modification that, when incorporated, repairs the damaged upper longeron area. The actions specified by this AD are intended to prevent cracking and subsequent failure of the longerons with consequent loss of control of the airplane.