The FAA on Tuesday issued an airworthiness directive that affects certain Teledyne Continental Motors reciprocating engines with TCM EQ3 cylinders installed. The AD applies to engines in the O-470, IO-470, TSIO-470, IO-520, TSIO-520, IO-550, and IOF-550 series, which are found in a variety of GA airplanes, including many Beech and Cessna models. TCM shipped engines with EQ3 cylinders and shipped individual EQ3 cylinders from Nov. 1, 2007, through Jan. 30, 2009. Also, TCM produced a group of about 300 EQ3 cylinders in August and September of 2006. The AD requires initial and repetitive visual inspections of TCM EQ3 cylinders for cracks. The EQ3 cylinders must be identified and initially inspected within 20 flight hours after Oct. 7, 2009, the effective date of the AD. Also, the AD requires that the cylinders must be removed from service within 1,300 hours total time of operation. This AD results from reports of 35 EQ3 cylinders found cracked, the FAA said.
Cracks in the cylinder head can cause engine failure or fire in the engine compartment, the FAA said. TCM investigated the cause of the cracks and found that their EQ3 configuration cylinder-head casting tool used in manufacturing created an area of reduced wall thickness, which can result in a crack in the area between the upper spark plug bore and the fuel injector/primer nozzle bore during operation. The FAA published the directive as a final rule, without any prior notice or opportunity for public comment. However, “relevant data, views, or arguments regarding this AD” are welcome, says the FAA. Instructions for filing comments can be found in the full text of the AD.