FAA Eases Impact of Superior Cylinder AD

Ruling prevents groundings of hundred of airplanes.

The FAA has signed off on an alternative method of compliance (AMOC) for a controversial airworthiness directive that could have grounded several hundred airplanes with Superior Air Parts aftermarket cylinders.

The original AD would have required replacement of the Superior cylinders in certain Continental engines after 12 years in service. Under the new AMOC guidelines, owners of aircraft who have over 12 years on their affected Millennium Cylinders but have not yet reached TBO will instead be able to comply with the AD through ongoing cylinder inspections.

The mandated tests will include visual inspection, compression check, leak check, and a borescope inspection every 50 flight hours or during the annual inspection, whichever comes first. Cylinders that pass the tests will be permitted to continue flying until reaching hourly or the mandated 17-year time-in-service limit.

Superior Air Parts estimates that the original AD as written could have immediately grounded more than 1,000 airplanes.

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