Continental provides clarity on crankshaft problem

The mandatory service bulletin issued February 13 requires piston removal to inspect crankshaft counterweight retaining rings for proper installation and correct a “potential assembly error” that affects about 2,000 crankshaft assemblies (installed and otherwise), Continental noted in the bulletin.

The bulletin was issued five days after Cirrus Aircraft announced the precautionary grounding of its own fleet of SR22 and SR22T models powered by Continental engines assembled since June 2021, a decision prompted by communication from Continental to Cirrus. The engine maker offered some additional details in a brief statement February 10, and the February 13 bulletin added further clarity. Only engines with less than 200 operating hours require immediate inspection, with “an additional five flight hours acceptable to move to a maintenance facility with minimum essential crew, if necessary.” No further action is required for engines with more than 200 operating hours.

“It is possible one or more counterweight retaining rings were not properly seated in the crankshaft counterweight groove,” the bulletin states. “This condition could allow the counterweight to depart from the crankshaft during engine operation resulting in catastrophic engine damage.”

A 24-page appendix to the eight-page bulletin lists affected engine and crankshaft serial numbers. The inspection costs are covered under warranty, and Continental detailed eligibility requirements that vary according to whether the affected crankshaft assembly has been installed, and by model and the number of cylinders required to be removed to complete the inspection. (Up to 22 labor hours are covered for six-cylinder engines from which three cylinders must be removed and reinstalled to complete the inspection, for example.) Continental detailed a procedure to obtain warranty reimbursement.

The service bulletin may become legally binding if the FAA incorporates it into an airworthiness directive.