Mandatory Service Bulletin Issued for Superior Millennium Cylinders

Three engine models are included in the required intake valve replacement.

Superior Air Parts’ service bulletin pertains to cylinders rebuilt or overhauled with Superior intake valves found on Continental 470-series engines, which are used to power a variety of aircraft, including Cessna 180s. [Credit: Shutterstock]

Superior Air Parts, Inc., has issued a mandatory service bulletin (MSB) requiring the replacement of intake valves used in new Superior Millennium Cylinders and cylinders rebuilt/overhauled with Superior intake valves found on Continental 470-, 520- and 550-series engines. 

According to a statement from Superior Air Parts, the MSB covers intake valves with part number SA539988. These intake valves were shipped between February 23, 2020 and January 20, 2022.

The MSB may be found here.

The issue, according to Bill Ross, vice president of product support for Superior Air Parts, is that the valves may fail during use.

“We have found three instances where the valves have failed in service,” Ross said. “Our overriding priority is always the safety of our customers and their aircraft. Therefore, after the required inspection, should an owner find that their aircraft has the affected intake valves installed, the aircraft is to be immediately grounded until the impacted cylinders can be replaced.”

Ross also stressed that because the intake valves were used by third-party cylinder overhaul/repair facilities, it is extremely critical that owners whose aircraft use rebuilt/overhauled cylinders using the Superior intake valves contact that shop to confirm whether or not the affected parts may have been used in their engines.

Meg Godlewski has been an aviation journalist for more than 24 years and a CFI for more than 20 years. If she is not flying or teaching aviation, she is writing about it. Meg is a founding member of the Pilot Proficiency Center at EAA AirVenture and excels at the application of simulation technology to flatten the learning curve. Follow Meg on Twitter @2Lewski.

Subscribe to Our Newsletter

Get the latest FLYING stories delivered directly to your inbox

Subscribe to our newsletter