Occurrences were reported of finding cracks on the NLG lower plate and its welding to the oleo outer cylinder. Technical investigations initially determined the cause of these cracks to be overstress in the NLG due to hard landings. Later occurrences were determined to have been due to fatigue failure of welding of the upper or lower plate to the NLG oleo outer cylinder.
This AD takes over the requirements for DR 253, DR 300 and DR 400 aeroplanes from EASA AD 2010-0231 (which will be cancelled), requires the new inspections at different intervals, and implementation of a life limit for the affected parts. This AD also requires replacing the affected parts with the latest CEAPR design, and introduction of the repetitive inspections into the approved aircraft maintenance programme.