Airworthiness Directive · Amendment 39-17304 · Flight controls
Burkhart GROB Luft- und Raumfahrt GmbH Sailplanes
This AD applies to Burkhart GROB Luft-und Raumfahrt GmbH Models GROB G 109 and GROB G 109B sailplanes, all serial numbers, certificated in any category.
We are adopting a new airworthiness directive (AD) for Burkhart GROB Luft- und Raumfahrt GmbH Models GROB G 109 and GROB G 109B sailplanes. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as corrosion and/or cracking of the elevator control rod that could lead to failure of the elevator control rod with consequent loss of control. We are issuing this AD to require actions to address the unsafe condition on these products.
Unless already done, do the following actions:
(1) Within the next 25 hours time-in-service (TIS) after February 13, 2013 (the effective date of this AD) or within the next 60 days after February 13, 2013 (the effective date of this AD), whichever occurs first, and repetitively thereafter at intervals not to exceed every 5 years, inspect the elevator control rod in the vertical fin for corrosion or cracking following the accomplishment instructions in Grob Aircraft AG Service Bulletin No. MSB817-64/2, dated September 6, 2012.
(2) For the purposes of this AD, we define slight corrosion as corrosion you can remove with metal wool and that has no visible pitting in the base metal. If you cannot remove the corrosion with metal wool or if there is visible pitting in the base metal, we define it as heavy corrosion.
(3) If any cracks or heavy corrosion are found during any of the inspections required in paragraph (f)(1) of this AD, before further flight, replace the elevator control rod with an airworthy part following the accomplishment instructions in Grob Aircraft AG Service Bulletin No. MSB817-64/2, dated September 6, 2012, for your applicable sailplane model.
(4) If only slight or no corrosion of the elevator control rod is found during any of the inspections required in paragraph (f)(1) of this AD, before further flight, clean the rod surface and apply a corrosion inhibitor, as applicable, following the accomplishment instructions in Grob Aircraft AG Service Bulletin No. MSB817-64/2, dated September 6, 2012.
Note 1 to paragraph (f) of this AD: Grob Aircraft AG incorporated the repetitive inspections required by this AD into the instructions for continued airworthiness of the aircraft maintenance manual for the applicable sailplanes.
