It was found that, in several cases during the daily inspection, clearly visible
cracks in the sailplane propeller hub were not detected by the pilot. The results
of a subsequent review revealed that the accomplishment instructions provided
to check the powered sailplane’s propeller hub and blades were not sufficient to
detect cracks and/or other damage.
This condition, if not corrected, could lead to propeller hub and/or blades
failure, possibly resulting in release of a propeller blade or of any major portion
of the propeller assembly and consequent loss of control of the powered
sailplane.
Zie:
http://ad.easa.europa.eu/ad/12-156