Lycoming Requires Conrod Inspections
Lycoming issued a Mandatory Service Bulletin on Monday that requires owners and operators of its engines to check them for connecting rods that contain bushings that do not meet Lycoming Engine’s specifications. The bushings were manufactured between specified date ranges from November 2015 to as late as February 2017. The service bulletin specifies the dates and part numbers. Lycoming said Tuesday that it didn't have an estimate of how many rods and bushings are impacted.
The SB contains a warning to owners: “You must complete the ‘Required Action’ in this Service Bulletin. If you do not complete the ‘Required Action’ in this Service Bulletin, and the connecting rod bushing moves out of place, the connecting rod can fail and cause un-commanded structural engine failure.”
The first step in the SB requires operators to check their engine serial numbers to identify affected engines. The SB applies to all engine models Lycoming makes, including factory-new and overhauled engines and, potentially, those overhauled by field shops. However, only a fraction of these have the suspect bushings. Lycoming estimates that about 1300 factory engines will require inspection, but a much smaller number will require bushing replacement.
If the engine is affected, the Lycoming parts source must be contacted to review all the engine paperwork to determine whether the engine could have one or more of the suspect connecting rod bushings or connecting rod assemblies. If the suspect parts are found, cylinders will have to be removed and the parts replaced. Lycoming is manufacturing a special tool to assist in this process. It estimates the work could take 12 hours for a four-cylinder engine and up to 20 hours for an eight-cylinder engine. The work may be covered under Lycoming's warranty, but it's unclear if field shops are expected to cover the costs of such work.