Airworthiness Directives; Fiberglas-Technik Rudolf Lindner GmbH & Co. KG (Type Certificate Previously Held by GROB Aircraft AG, Grob Aerospace GmbH i.l., Grob Aerospace GmbH, Burkhart Grob Luft- und Raumfahrt GmbH & Co. KG) Gliders

The FAA is adopting a new airworthiness directive (AD) for all Fiberglas-Technik Rudolf Lindner GmbH & Co. KG Model G103 TWIN II, G103A TWIN II ACRO, G103C TWIN III ACRO, and G 103 C TWIN III SL gliders. This AD was prompted by a report of corrosion on the inner sides of the welded steel rudder drive plate. This AD requires repetitive inspections and a one-time detailed inspection of the rudder drive plate for corrosion and water entry and a modification of the rudder drive plate to improve corrosion protection, as applicable. This AD also requires replacement of the rudder if corrosion is found during the inspections that exceed light surface rust. This AD also requires applying additional sealing to the rudder drive plate, which constitutes terminating action for the repetitive inspections. The FAA is issuing this AD to address the unsafe condition on these products.