Engines that would be subject to the AD are equipped with an F&M Enterprises Inc. (F&M) or Stratus Tool Technologies LLC (Stratus) oil filter adapter installed under Supplemental Type Certificate SE8409SW, SE09356SC, or SE10348SC.
Affected models include members of the Continental Aerospace Technologies C-125, C145, IO-360, IO-470, IO-550, O-300, O-470, TSIO-360, and TSIO-520 series as well as some Continental Motors IO-520 engines that have the oil filter adapter installed.
The FAA estimates that 6,300 U.S.-registered aircraft are subject to the AD at an estimated cost of $246.50 per aircraft including the $34 replacement gasket.
Comments may be submitted on the AD until November 26.
According to the AD, any F&M or Stratus oil filter adapter fiber gasket must be removed from service and replaced with a Stratus AN900-28 or AN900-29 oil filter adapter copper gasket before the engine accumulates 50 flight hours after the effective date of the AD, or at the next scheduled oil change after the effective date, whichever occurs first.
In December 2020, AOPA reported that the NTSB had urged the FAA to address safety concerns about the aftermarket oil filter adapter that was manufactured by F&M Enterprises from 1996 to 2015, and subsequently manufactured by Stratus Tool Technologies, an affiliate company of Tempest Aero Group.
In an official safety recommendation, the NTSB cited oil leaks associated with at least 11 accidents since 2004 and noted that accident investigations revealed “torn and unevenly compressed gaskets and loose adapters.”
Both the NTSB and the FAA referred to a May 1, 2019, accident near Mill Creek, California, involving a Cessna 182 that lost power and crashed after striking a power line, killing a passenger and seriously injuring the pilot and another occupant. A Cessna 210D that lost engine power and crashed near Ramona, California, in June 2019 had oil-leak evidence “similar to the earlier accident,” the NTSB said.
The AD notes that “an improperly maintained or installed oil filter adapter may lead to failure of the fiber gasket, which may result in oil loss or oil starvation.”
Pilots may comment on the proposed AD online or by mail to U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. Please include “Docket No. FAA-2021-0875; Project Identifier AD-2021-00675-E” at the beginning of your comments.