Airworthiness Directives; Teledyne Continental Motors (TCM) IO-520, TSIO-520, and IO-550 Series Reciprocating Engines With Superior Air Parts, Inc. (SAP) Cylinder Assemblies Installed

The FAA is adopting a new airworthiness directive (AD) for certain TCM IO-520, TSIO-520, and IO-550 series reciprocating engines, with certain SAP investment cast cylinder assemblies installed. This AD requires initial and repetitive inspections and compression tests to detect cracks in those cylinders with more than 750 flight hours (FH) time-in-service (TIS). This AD results from reports of cracks in the area of the exhaust valve and separation of cylinder heads from the barrels of SAP cylinder assemblies with certain part numbers. We are issuing this AD to prevent the separation of the cylinder head, which could result in immediate loss of engine power, possible structural damage to the engine, and possible fire in the engine compartment.