Proposed AD focuses on thin walls of Superior cylinders
Reports of 24 Superior cylinder assemblies with cracks or separation near the exhaust valves prompted the FAA to determine that the cylinder wall was significantly thinner in the areas where the cracks occurred.
The problem could lead to the cylinder head’s separation, resulting in engine failure, engine damage, or even fire in the engine compartment. Cracking or separation typically occurred between 823 and 1,985 hours time since new on engines that were predominantly operated at low altitudes and had a high ratio of takeoffs and landings per flight hour.
Cylinder assemblies would need to be inspected, and replaced if necessary, within 25 flight hours time in service after the AD went into effect. Then, the cylinder visual inspections and compression tests would need to be repeated within every 50 flight hours after the last inspection until the cylinders reached their time-before-overhaul limits.
AOPA will be asking the FAA to thoroughly review all of the data and comments to determine if it is possible to make the repetitive checks and tests required at every 100 hour or annual inspection, whichever comes first.
AOPA suggests that pilots who are planning to comment on the proposed AD include their cylinders’ time in service, type of engine operation, any service difficulties (cracks and/or separated cylinders including the times on the cylinders when the event occurred), and whether the cylinder has gone to TBO. Comments must be sent by June 10.
To file comments online, visit the Federal eRulemaking Portal and follow the instructions for submission. Comments can also be mailed to: Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Ave. SE, West Building Ground Floor, Room W12-140, Washington, DC 20590-0001. Include “Docket No. FAA-2007-0051; Directorate Identifier 2007-NE-37-AD” in your comments.
May 22, 2008