Continental Motors has discovered a potential assembly error affecting approximately 200 crankshaft assemblies. It is possible one or more counterweight retaining rings were not properly seated in the crankshaft counterweight groove. This condition could allow the counterweight to depart from the crankshaft during engine operation resulting in catastrophic engine damage. Please see Continental Motors MSB 23-01 (link below) for effected models and serial numbers and the FAA issued Airworthiness Directive AD 2023-04-08.
https://www.faasafety.gov/files/notices/2023/Feb/23-01_Mandatory_Service_Bulletin.pdf
Airworthiness Directive Link:
https://www.faasafety.gov/files/notices/2023/Feb/AD2023-04-08_Continental_Motors_Snapring.pdf
For further information, please reference the Related Information on the last page of the AD
or email:
Kyle Weinzirl Anchorage FAA Safety Team kyle.weinzirl@faa.gov