The FAA has issued tonight an emergency airworthiness directive (AD) immediately grounding certain aircraft powered by Lycoming TIO-540 and LTIO-540 engines producing 300 horsepower or more. Aircraft affected include the Piper Navajo, Malibu Mirage, Saratoga, and the Cessna Turbo Stationaire. The emergency AD is intended to prevent crankshaft failure and subsequent catastrophic engine failure.
Specific crankshafts involved were manufactured between early 1999 and early 2002. Engines with replacement crankshafts installed under superseded AD 2002-04-51 issued in February may also be affected.
The emergency AD requires replacement of certain crankshafts (listed by serial number in Lycoming Service Bulletin No. 552). Owners of affected airplanes are required to replace crankshafts prior to further flight and are instructed to contact Lycoming at 570/323-6181.
According to the FAA, a variation in the heat treatment process used during production of the crankshafts appears to be the cause for the metallurgical deficiency that may have led to crankshaft failure. Although the NTSB has not yet issued an official safety recommendation, the FAA is taking action based on safety concerns highlighted by a fatal Piper Malibu Mirage accident in Michigan earlier this month.
The FAA estimates that it may take as long as eight months for enough replacement crankshafts to be produced. Lycoming says it is working to ramp up production and will provide replacement parts to owners as quickly as possible.
The FAA will issue ferry permits to allow affected owners to reposition aircraft for AD compliance.