Airworthiness Directive · Amendment 39-23160 · Rudder control system
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
This AD applies to 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) Model G103 TWIN II, G103A TWIN II ACRO, G103C TWIN III ACRO, and G 103 C TWIN III SL gliders, certificated in any category.
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.
For the purpose of this AD, a “serviceable rudder” is a rudder which has accumulated zero hours time-in-service (TIS), or a rudder that has been inspected and modified, as necessary, in accordance with paragraphs (h)(1) and (2) of this AD and is found to be crack and corrosion free.
(1) Within 50 hours TIS or 3 months, whichever occurs first after the effective date of this AD, and, thereafter, at intervals not to exceed every 12 months, inspect the rudder drive plate for evidence of corrosion or water entry in accordance with the Actions and Instructions, section A, of Fiberglas-Technik Rudolf Lindner Service Bulletin SB-G10, Revision 1, dated February 27, 2025.
(2) Perform a one-time detailed inspection of the rudder drive plate in accordance with the Actions and Instructions, section B, steps 1 and 2 of Fiberglas-Technik Rudolf Lindner Service Bulletin SB-G10, Revision 1, dated February 27, 2025, at whichever compliance time in paragraphs (h)(2)(i) or (ii) of this AD occurs first.
(i) Before further flight if during any inspection as required by paragraph (h)(1) of this AD, evidence of corrosion or water ingress is found; or
(ii) At the next service life extension inspection that occurs after the effective date of this AD.
(3) If, as a result of the inspection required by paragraph (h)(2) of this AD, corrosion of the rudder drive plate is detected that exceeds light surface rust and cannot be removed using steel wool, before further flight, replace the rudder with a serviceable rudder, or contact the Manager, International Validation Branch, FAA; or EASA; or Fiberglas-Technik Rudolf Lindner GmbH & Co. KG EASA Design Organization Approval (DOA) for approved instructions. If approved by the DOA, the approval must include the DOA-authorized signature.
(4) If the rudder is replaced with a serviceable rudder, before further flight, apply additional sealing to the rudder drive plate in accordance with the Actions and Instructions, Section C, of Fiberglas-Technik Rudolf Lindner Service Bulletin SB-G10, Revision 1, dated February 27, 2025.
(5) If, as a result of the inspection required by paragraph (h)(2) of this AD, light surface rust is detected, before further flight, modify the rudder drive plate in accordance with the Actions and Instructions, section B, steps 4 through 7 of Fiberglas-Technik Rudolf Lindner Service Bulletin SB-G10, Revision 1, dated February 27, 2025.
(6) If, as a result of the inspection required by paragraph (h)(2) of this AD, no evidence of corrosion or water ingress is detected, before further flight, modify the rudder drive plate in accordance with the Actions and Instructions, section B, steps 5 through 7 of Fiberglas-Technik Rudolf Lindner Service Bulletin SB-G10, Revision 1, dated February 27, 2025.
(7) Following completion of the modification of the rudder drive plate required by paragraph (h)(5) or (h)(6) of this AD, before further flight, apply additional sealing to the rudder drive plate in accordance with the Actions and Instructions, Section C, of Fiberglas-Technik Rudolf Lindner Service Bulletin SB-G10, Revision 1, dated February 27, 2025.
(8) Following completion of the sealing application required by paragraph (h)(7) of this AD, re-install the rudder in accordance with the Actions and Instructions, Section D, of Fiberglas-Technik Rudolf Lindner Service Bulletin SB-G10, Revision 1, dated February 27, 2025.
(9) Application of additional sealing to the rudder drive plate, as required by paragraphs (h)(4) and (h)(7) of this AD, constitutes terminating action for the repetitive inspections required by paragraph (h)(1) of this AD for that glider.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
