Superior Air Parts has issued a Mandatory Service Bulletin requiring the replacement of intake valves in certain Millennium cylinders and rebuilt/overhauled cylinders used in Continental 470-, 520-, and 550-series engines.

The Mandatory Service Bulletin covers new Superior Millennium Cylinders and cylinders rebuilt/overhauled with Superior intake valves with part number SA539988 shipped between January 20, 2022, and February 23, 2020.

“We have found three instances where the valves have failed in service,” stated Bill Ross, VP of Product Support for Superior Air Parts. “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.

For more information and to download a copy of MSB22-01, visit:

Customer contact: Bill Ross, Vice President of Product Support, 214-395-9183.

For more information, visit