Lycoming said that a Notice of Proposed Rulemaking (NRPM) would be issued by Friday with an AD to follow, making the new MSB truly mandatory for Part 91 operators. According to Lycoming president Ian Walsh, “We had enough incidences to finally decide that all cranks with the same ‘heat code’ manufactured by Interstate should be recalled.” These crankshafts are found in a wide array of Lycoming six- and four-cylinder engines, even some low-power, 180-hp O-360 applications. Crankshafts for the high-power engines that were caught in the previous recall are not affected. Affected crankshafts have a serial number starting in V5379, although not all cranks in that series are covered under the MSB. (See Lycoming’s Web site for the full text of the MSB and a listing of affected engines and crankshafts.) In the MSB, Lycoming lists somewhere near 1056 engines and 227 crankshafts by serial number, impacting O-540, IO-540, AEIO-540 and TIO-540 engines rated at 290 hp and lower; IO-540-P, -S, and -AA engines rated between 250 and 290 hp; IO-540 and AEIO-540 engine rated at 300 hp; and counterweighted O-360, IO-360, and TIO-360 engines rated at any horsepower. Also, Lycoming has called out a set of specific serial-number crankshafts that may have been sold as spares since March 1, 1999.
