Get the latest news on coronavirus impacts on general aviation, including what AOPA is doing to protect GA, event cancellations, advice for pilots to protect themselves, and more. Read More
Already a member? Please login below for an enhanced experience. Not a member? Join today

Regulatory Brief: Lycoming Crankshaft ReplacementRegulatory Brief: Lycoming Crankshaft Replacement

Regulatory Brief: Lycoming Crankshaft Replacement

The issue

On July 11, 2005, Textron Lycoming issued a mandatory service bulletin (SB) requiring the replacement of more than 1,100 Lycoming crankshafts installed in certain 360 and 540 engines manufactured, rebuilt, overhauled, or repaired after March 1, 1999. The FAA subsequently issued two airworthiness directives (ADs), making the requirements of Lycoming SB 566 and its associated supplement 1 mandatory for Part 91 aircraft owners.

On February 21, 2006, Lycoming issued mandatory service bulletin 569, which was later superseded by SB 569A, calling for the retirement of over 5,000 crankshafts in engines ranging from the O-360 to the IO-720.

Based in part on SB 569 and 569A, the FAA issued an AD in September 2006 that required the replacement of certain crankshafts in some 3,800 Lycoming 360- and 540-series reciprocating engines in popular Piper, Cessna, Mooney, and Beechcraft aircraft, among others.

The importance to our members

Lycoming’s SB 566 and supplement 1 affects over 1,100 aircraft, the majority being Robinson helicopters, followed by late-model Cessna 182s and some Piper and other models, including Mooney M20J/M and Commander 112/114.

SB 566 is a continuation of a problem that affected crankshafts in high-powered, turbocharged Lycoming engines. Improperly hammer-forged crankshafts resulted in several crankshaft failures, prompting the FAA to issue AD 2002-17-53 and later AD 2002-19-03, which required replacing the deficient crankshafts with press-forged crankshafts.

For engines affected by SB 566, SB 566 supplement 1, and related ADs, Lycoming will pay for replacing the crankshaft and shipping the engine to and from Lycoming’s Williamsport, Pennsylvania, factory to accomplish the work. The company will also pay a reasonable amount for the labor involved to remove and reinstall the engine.

For the crankshafts affected by SB 569A, Lycoming is offering to provide a $2,000 “crankshaft kit,” if the crankshaft is replaced during the compliance period outlined in the SB. Lycoming’s SB 569A calls for the crankshaft to be replaced at the first crankcase separation, or at the next overhaul, whichever occurs first but no later than February 21, 2009.

The compliance timeframe specified in the AD differs from Lycoming’s SB 569A. The AD requires that the crankshaft be replaced at the earliest of the following: the time of the next engine overhaul as specified by Lycoming, the next separation of the crankcase, or no later than 12 years from the time the crankshaft first entered service or was last overhauled.

If aircraft owners decide to have their engines overhauled at Lycoming (before or after February 21, 2009), Lycoming will replace the crankshaft for free as part of Lycoming’s “no charge back” core policy. For specific questions regarding Lycoming’s “no charge back” core policy or coverage under the SB, owners can contact Lycoming.


  • September 26, 2006, the FAA issues final AD affecting 3,800 Lycoming engines
  • May 25, 2006, the FAA issued a proposed AD that would require the replacement of certain crankshafts in some 3,800 Lycoming 360- and 540-series reciprocating engines at overhaul or during maintenance on the existing crankshaft.
  • April 11, 2006, Lycoming issued SB 569A superseding SB 569.
  • April 7, 2006, AOPA objects to Lycoming crankshaft retirement airworthiness concern sheet.
  • March 23, 2006, the FAA issued a final AD requiring the replacement of approximately 300 additional Lycoming -360 engine crankshafts.
  • February 21, 2006, Lycoming issued SB 569 calling for the retirement of over 5000 crankshafts not subject to earlier service bulletins requiring crankshaft replacement.
  • December 27, 2005, the FAA issued a proposed AD that expands the current Lycoming crankshaft AD to cover an additional 325 aircraft.
  • September 16, 2005, the FAA issued a final AD affecting over 1,100 Lycoming engine crankshafts.
  • July 22, 2005, the FAA issued a proposed AD that would make Lycoming’s SB 566 mandatory.
  • July 11, 2005, Lycoming issued SB 566 calling for the crankshaft replacement in certain Lycoming 360 and 540 engines.

Updated March 26, 2008