New oil gasket AD affects thousands of Continental engines

The new AD is the latest iteration in a series issued since an NTSB investigation prompted that agency to recommend an FAA directive requiring inspections of aftermarket oil filter installations on various Continental engines. The NTSB issued a 2020 press release calling for an AD on the adapter manufactured by F&M Enterprises, and later by Stratus Tool Technologies, an affiliate of Tempest Aero Group. Oil leaks traced to faulty adapter installations, or gasket failures, were connected to at least 11 accidents involving three fatalities at the time.

The FAA issued a proposed AD in October 2021 that was followed by a supplemental notice of proposed rulemaking in June, prompted by a report from an individual who reported that the prior AD omitted certain engine models, and who noted manufacturer revisions were also omitted. The FAA added various engine models, and removed others (with permold type crankcases) that had been inadvertently included.

The resulting AD, effective October 26, applies to Continental engine models C–125, C145, IO–360, IO–470, IO–550, O–300, O–470, TSIO–360, and TSIO–520 series engines, as well as certain IO–520 engines with a certain oil filter adapter installed. A preceding AD required replacing a fiber oil filter gasket with a copper gasket. The new AD requires replacing the fiber gasket with a copper gasket or a stainless-steel gasket embedded with polytetrafluorethylene (PTFE).

The FAA estimates the cost of compliance, including 2.5 work hours and a $34 part, will amount to $246.50 for each aircraft, or $1.5 million to cover the estimated 6,300 engines installed with the applicable oil filter adapter assembly.