Airworthiness Directive · Amendment 39-21897 · Powerplant system
Stemme AG Gliders
Superseded. A later AD replaced this one: AD 2023-02-03. Comply with the one in force.
This AD applies to Stemme AG Model Stemme S 10-VT and Stemme S 12 gliders, all serial numbers, certificated in any category, with a freewheel clutch part number (P/N) 12AK with a serial number(S/N) starting with “12-” installed.
Note 1 to paragraph (c): Stemme Service Bulletin Doc. No. P062-980058, Revision 1, dated December 14, 2021, contains guidance for identifying the S/N of a P/N 12AK freewheel clutch.
The FAA is adopting a new airworthiness directive (AD) for certain Stemme AG Model Stemme S 10-VT and Stemme S 12 gliders. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI identifies the unsafe condition as unintended slipping of the freewheel clutch with overheating (burnishing) of the friction pads inside of the clutch. This AD requires removing the affected freewheel clutch from service. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Before further flight after the effective date of this AD, remove the freewheel clutch from service.
(2) As of the effective date of this AD, do not install a freewheel clutch P/N 12AK with an S/N starting with “12-” on any 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.
