FAA-2010-0308 Thielert Aircraft Engines GmbH Model TAE 125-01 Reciprocating Engines

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Service has shown that the small outlet of the blow-by oil separators, part number 02-7250-18100R1; 02-7250-18100R2; 02-7250-18100R3; 02-7250-18100R4; 02-7250-18300R1; 02-7250-18300R2; 02-7250-18300R3; 02-7250-18300R4; or 02-7250-18300R5, may cause a blow-by gas pressure increase inside the crankcase of the engine in excess of the oil seal design pressure limits. Leaking engine oil may adversely affect the gearbox clutch or the engine lubrication system. This condition, if not corrected, could lead to in-flight cases of engine power loss or ultimately, shutdown.

We are issuing this AD to prevent loss of engine power or uncommanded engine shutdown during flight due to excessive crankcase blow-by gas pressure.