The New MSB (AD Expected Soon)
The ongoing controversy surrounding Lycoming crankshafts took a new twist Monday as the company issued Mandatory Service Bulletin (MSB) 566, which greatly widens the net draping a crankshaft issue previously limited to high-horsepower six-cylinder engines (often found in high-stress turbocharged applications). The new MSB recalls crankshafts in more than 1000 engines manufactured, rebuilt, overhauled or repaired since March 1, 1999. In addition, some 227 crankshafts not affiliated with a specific engine serial number are also affected. This is a group of engines distinct from the set of high-power, six-cylinder Lycomings that have been subject to a previous recall and Airworthiness Directive (AD) for crankshaft replacement. Time of compliance is listed as within the next 50 hours or six months and, as Part 91 operators know, a Mandatory Service Bulletin is not a defining rule as is an Airworthiness Directive. Ian Walsh, Lycoming president, says, “We’ve been watching the data since 2002 and have come to the conclusion that we need to expand the scope” to include other crankshafts.
