Lycoming: No Labor Allowance For Conrod Bushing Fix


Owners impacted by the recently announced Lycoming connecting rod bushing service bulletin will be on their own to pay labor charges, the company told AVweb this week. However, Lycoming will provide the necessary parts. Customers who bought factory engines still covered under warranty will be afforded a labor allowance, according to Lycoming.

As we reported earlier this week, Lycoming Mandatory Service Bulletin 632 requires owners and operators of all Lycoming engines—regardless of model—to check them for off-spec connecting rod bushings within the next 10 hours of flight. According to the SB, the bushings were shipped from the factory between Nov. 18, 2015, and Nov.15, 2016. In addition, Lycoming also shipped defective connecting rod assemblies during periods between Nov. 20, 2015, and Feb. 2, 2017. These are also subject to the SB. The FAA is considering whether to issue an AD requiring the inspection and replacement of the problem bushings.

Lycoming says it doesn’t yet have a count on how many individual bushings and rod assemblies are affected. This week, AVweb polled three engine shops who were reviewing their records to see how many engines might be impacted. All three shops told us they’ve received many calls from customers seeking clarity on the SB requirements and thus far, none had heard from Lycoming concerning factory support for defective parts and labor charge reimbursement.

The suspect bushings are improperly machined and allow the piston end of the connecting rod to move side to side, potentially causing rod failure. Lycoming says there have been engine failures and two of the three shops we contacted said customers had experienced complete or partial engine failures as a result of the defective bushings. In December 2016, the New Zealand CAA issued a continuing airworthiness bulletin warning of the problem bushings after at least two failures were reported.

The SB provides a long list of serial numbers and models that must be checked. For many owners, this will be a paperwork exercise to rule out or in the use of problem bushings. Engines equipped with aftermarket PMA bushings from other sources aren’t affected.

If the engine’s bushings fall within the specified serial/date ranges, the SB describes an involved inspection process that requires removing the cylinders and using a special, Lycoming-provided tool to determine whether the bushing’s dimensions allow side-to-side movement. Lycoming has been manufacturing the tools for field distribution. The SB specifies that the piston not be removed from cylinder assembly to avoid additional labor and parts requirements.

If bushing movement is detected, the rods have to be removed and returned to Lycoming for replacement. If the bushings don’t move, the engine can be reassembled and returned to service. Lycoming will supply the required replacement parts, but labor is up to the customer or field shop unless the engine is covered under factory warranty. Lycoming told AVweb earlier this week that customers should contact their engine shops to inquire about warranty performance from the shop.

For factory warranty purposes, SB 632 allows 12 hours of labor for a four-cylinder engine and 16 hours for a six-cylinder engine. If problem bushings are found, owners should expect some downtime to allow for the rods to be shipped back to Lycoming for replacement and processing. With labor billed at at least $80 an hour, shops or owners not covered by warranty can expect charges between $1200 and $2000 on the low side and as much as twice as that on the high side, according to one shop owner we spoke to.