Additional 300 Cylinders Added To MSB Revision

Teledyne Continental Motors has issued its first revision to a Mandatory Service Bulletin issued last month, calling for replacement of certain cylinders. The updated MSB adds 300 additional cylinders, manufactured since August 2006... 15 months longer than the original timeline.

As ANN reported, on February 12 TCM issued a voluntary recall on certain piston cylinders produced and shipped since November 2007, after owners reported cylinder head cracking found during regular maintenance inspections. That MSB affected cylinders on certain 470, 520 and 550 series engine models; the expanded MSB covers the same engine modes, but now indicates problems may have appeared on cylinders older than in the original timeframe.

Per the MSB, "TCM has determined that the EQ3 cylinder head casting tool used in the manufacturing process created an area of reduced thickness that may result in a crack after prolonged operation. This crack manifests itself in the area between the upper sparkplug bore and the fuel injector/primer nozzle bore.

"The cracked cylinders returned to date have occurred on engines from high use fleet operations with occurrence times ranging from approximately 430 to 1,300 total hours. Replacement cylinders conforming to proven production history will be provided."

There have been no reported accidents or incidents stemming from the manufacturing defect.

The company hopes to avoid issuance of an Airworthiness Bulletin on the problem, stating it believes all suspect cylinders can be replaced within the next year, on TCM's dime.

FMI: Read The Updated MSB (.pdf)