Mooney M20TN Acclaim Type S — Normal Procedures

This Service Bulletin M20-312, dated June 27, 2011, addresses the inspection and cleaning of the crankcase breather tube for the Mooney M20TN Acclaim Type S aircraft equipped with the TSIO550G engine. It highlights the potential issue of oil coking and deposit buildup at the crankcase breather outlet tube, which can lead to increased crankcase pressures and oil consumption. The bulletin provides detailed instructions for pilots and maintenance personnel on how to inspect, clean, and replace the breather tube and hoses as necessary. Compliance with this bulletin is crucial for maintaining engine performance and reliability, and it should be completed within the next 15 flight hours or at intervals not exceeding 100 hours of service.

• Inspect crankcase breather tube within the next 15 flight hours or at intervals not exceeding 100 hours.
• The outlet opening of the breather tube should be approximately 5/8 in. (0.625 in.) when clear.
• Use a hard wire brush and solvent for cleaning the breather tube; avoid damaging the tube.
• Replace any damaged breather hoses with part number 628555-45, trimmed to fit.
• Document compliance with the bulletin and return to Mooney Airplane Company.