NTSB flags oil-filter adapter in Continental engine failures

In a December 3 news release, the NTSB called on the FAA to issue an AD on the oil filter adapter manufactured by F&M Enterprises from 1996 to 2015, and now manufactured by Stratus Tool Technologies, an affiliate company of Tempest Aero Group.

Oil leaks from adapters have led to at least 11 accidents involving three fatalities and five serious injuries since 2004, the NTSB said in a Safety Recommendation Report. Other safety issues identified during accident investigations included “torn and unevenly compressed gaskets and loose adapters.”

A supplemental type certificate (STC) permits installation of the adapter on some Continental engines that power numerous models of general aviation single- and twin-engine airplanes. The STC allows a “conventional spin-on oil filter” to be used instead of “the brass screen on the original engines,” the NTSB said.

Issuing an AD is called for, the NTSB added, “because compliance with service bulletins is not mandatory for Part 91 operators.”

AOPA encourages aircraft operators to follow the manufacturer’s safety guidance.

“AOPA recommends aircraft owners with the adapters comply with the manufacturer’s service bulletin in anticipation of the FAA issuing an AD,” said Murray Huling, AOPA vice president of regulatory affairs. “We believe aircraft owners understand the importance of the fix and will take the appropriate actions to eliminate the identified risk."

On December 8, the AOPA Air Safety Institute published a Safety Notice to help inform aircraft operators about the NTSB’s recommendation.

The service bulletin that the NTSB wants to be used as the basis for an AD was issued by Stratus Tool Technologies in October 2019 in response to these problems and other reports of oil leaks, the NTSB said.

The document provides installation and maintenance instructions for mechanics and advises aircraft owners when the oil filter adapters should be inspected.