The FAA has acceded to AOPA's request and is now circulating an Airworthiness Concern Sheet on the latest Lycoming crankshaft service bulletin (SB). That means the FAA's Engine and Propeller Directorate will attempt to gather real-world data before deciding whether to issue an airworthiness directive (AD) on Lycoming crankshafts not already covered by two previous ADs.
AOPA members can help guide the process.
"We need data from aircraft owners who are affected by the Lycoming SB," said Luis Gutierrez, AOPA director of regulatory and certification policy. "We're asking members to fill out a simple, online form. We think the data will show that the SB represents a significant economic impact on owners unjustified by the potential safety risk."
So how to determine if your aircraft is affected?
If Lycoming has already repaired your engine under one of the two previous ADs (2002-19-03 or 2005-19-11) and your crankshaft hasn't been replaced since, you are in the clear.
If your engine was manufactured or had its crankshaft replaced prior to March 1, 1997, or after July 11, 2005, you're OK. But if your engine was built or had its crankshaft replaced within that eight-year period, you may have a crankshaft that Lycoming wants to "retire."
So, next step, look at the engine model number. If you have a Lycoming counterweighted engine, models (L)O-360, (L)IO-360, HIO-360, AEIO-360, IO-390, AEIO-390, O-540, IO-540, AEIO-540, (L)TIO-540 IO-580, AEIO-580, or IO-720, you'll have to check the engine and/or crankshaft serial numbers to see if you're affected.
In most cases, you can find the engine serial number in your engine logbook. Alternatively, you can ask the shop that did your last major overhaul; they should have a record of your serial numbers and can likely tell you if your engine is affected.
Once you know your serial number, check it against the list in Lycoming Service Bulletin 569.
If your crankshaft was replaced between 1997 and 2005, there is a chance that your engine serial number won't be listed, but the crankshaft itself is still on Lycoming's "retire" list. Crankshaft serial numbers are stamped on the outer diameter of the propeller mounting flange (your shop can help you find it). The SB also lists crankshaft serial numbers.
If your engine is affected by this SB, Lycoming wants you to "retire" the crankshaft at overhaul or whenever the crankcase is split, or within three years, whichever comes first.
"But it's important to remember that there have been no failures among the crankshafts listed in the SB," said Gutierrez, "and private operators don't have to comply with a service bulletin, even if the manufacturer says it's 'mandatory.'" (Part 135 operators and others using aircraft in for-hire operations are generally required to comply with SBs.)
AOPA will be using the data collected from the aircraft owner survey to show the FAA that the Lycoming SB should not be made a mandatory AD as it is presently written.
"Given the absence of any engineering or field data showing that there is a risk to safety, the wholesale replacement of these crankshafts is unwarranted and an unacceptable expense to aircraft owners," said Gutierrez.
March 8, 2006