AD 2022-14-11 Requires Inspecting The Left-Hand (LH) And Right-Hand (RH) Outer Wing Spars

The FAA is adopting a new airworthiness directive (AD) for certain Stemme AG (type certificate previously held by Stemme GmbH & Co. KG) Model Stemme S 12 gliders.

This AD was prompted by mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI identifies the unsafe condition as a deviation in the construction of the connection of the inner wing to the outer wing, resulting in a wrong positioning of the glass-fiber reinforced plastic (GFRP) blocks. This AD requires inspecting the left-hand (LH) and right-hand (RH) outer wing spars for correct positioning of the GFRP blocks and, if incorrect positioning is found, repairing of the reinforcement blocks. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective July 26, 2022. 

Supplementary Information: The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA Emergency AD 2022-0101-E, dated June 2, 2022 (referred to after this as “the MCAI”), to address an unsafe condition on certain serial-numbered Stemme AG Model Stemme S12 powered sailplanes (gliders). The MCAI states:

• An occurrence was reported by the production line of the Stemme S12 of finding a deviation in the construction of the connection of the inner wing to the outer wing, resulting in a wrong positioning of the glass-fibre reinforced plastic (GFRP) blocks in the outer wing spar.
• This condition, if not corrected, could lead to loss of structural integrity at the joint (connection) between the outer wing and inner wing, possibly resulting in rupture of the affected wing, with consequent loss of control of the sailplane.
• To address this potential unsafe condition, Stemme identified the sailplanes possibly affected by this unintended production deviation and issued the SB [service bulletin], as defined in this [EASA] AD, to provide instructions to determine the (correct) positioning of the GFRP blocks in the outer wing spars.
• For the reasons described above, this [EASA] AD requires a one-time inspection of each affected part and, depending on findings, accomplishment of applicable corrective action(s). 
• This [EASA] AD is considered to be an interim action and further AD action may follow. 

You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2022-0809.

FMI: https://www.regulations.gov