ERA22LA071

During cruise flight, the pilot noticed a drop in engine oil pressure and turned toward the closest airport. The pilot subsequently elected to perform a precautionary off-airport landing during which the airplane sustained substantial damage. A postaccident examination of the engine revealed that it was equipped with a screw-on oil filter adapter. Oil seepage was found on the area surrounding the oil filter adapter attachment point, in the engine compartment, and on the underside of the fuselage. Examination of the adapter found its tightening torque to be 38.5 ft-lbs, which was below the prescribed installation torque of 65 ft-lbs. Additionally, the adapter was found installed with the originally specified fiber gasket, which the manufacturer had subsequently advised to remove and replace with a copper gasket in a mandatory service bulletin. The fiber gasket was found torn and indented. It is likely that the loose adapter and the torn fiber gasket allowed the engine oil to be pumped overboard. This ultimately resulted in the loss of oil pressure and the pilot’s decision to perform the precautionary off-airport landing. It is likely that had the mandatory service bulletin been complied with, the loss of oil pressure would not have occurred.

On November 21, 2021, at 0826 central standard time, a Cessna 210 airplane, N5779J, was substantially damaged when it was involved in an accident near Brent, Alabama. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. While on an instrument flight rules flight plan, and during cruise flight about 14 minutes after takeoff from Tuscaloosa Regional Airport (TCL), Tuscaloosa, Alabama, the airplane’s flight system monitor annunciated “check oil pressure.” The pilot checked his instruments and noted that the oil pressure indicated 0 psi. The pilot declared an emergency and established best glide speed, then navigated toward the closest airport. The pilot was cleared to descend and air traffic control inquired whether the plot would be able to reach the diversion airport. Given the circumstances, the pilot decided it was prudent to land immediately. During the descent the pilot descended out of the cloud cover and selected a road for a forced landing site. After touchdown, the airplane’s right wing collided with several road signs before the airplane impacted a ditch and several trees, coming to rest upright in a nose-down attitude. Postaccident examination of the wreckage by a Federal Aviation Administration (FAA) inspector revealed that the fuselage, firewall, and both wings sustained substantial damage and the tail cone exhibited compression wrinkling forward of the vertical stabilizer. The front windscreen was broken. The left-wing fuel tank was breached with no fuel remaining. The right-wing fuel tank remained intact and contained fuel. Data downloaded from the JPI EDM-830 engine data monitoring device revealed normal engine operation until 0818 when the oil pressure began to drop. Shortly thereafter the manifold pressure decreased and there was a corresponding reduction in recorded values for most other engine parameters. Around this time, recorded GPS data showed the aircraft began to descend from 7,000 ft mean sea level. The data ended at 0826. Examination of the engine revealed that it was equipped with an F&M screw-on oil filter adapter. Oil was observed on the lower area of the oil adapter fiber gasket seal (see figure 1), in the engine compartment and on the underside of the fuselage. The oil filter adapter installation was tested using a digital torque wrench. The tightening torque was measured at 38.5 ft-lbs. The loosening torque (breakaway torque) measured was 34.0 ft-lbs. Per the Stratus Tools Technologies mandatory service bulletin (SB) SB-001Rev B, revised June 17, 2021(originally issued October 25, 2019), the oil adapter transfer cylinder was to be tightened to 65 ft-lbs during installation. Upon removal of the oil filter adapter, examination revealed a fiber gasket between the airplane’s engine oil pump assembly and the oil filter adapter was torn and indented (see figure 2). Figure 1: Oil around oil adapter fiber gasket seal. Figure 2: Torn, indentedfiber gasket. The revised SB also required the removal of the fiber gasket (if installed) and replacement with a copper gasket, as well as inspection of the adapter for security, leaks, seepage, or gasket damage “within the next 10 flight hours, annual inspection, or 100-hour inspection, whichever occurs first.” The SB further stated that the use of fiber gaskets had been discontinued and that “only copper gaskets are approved for initial installation or reinstallation of F&M or Stratus Tool Technologies oil filter adapters.” A review of the airplane’s maintenance records found no entries that specifically addressed the SB. The most recent entry related to the adapter was in May 2015 when the adapter was removed, and the “gasket and crush washer” were replaced. During a postaccident interview, the pilot stated that he had not experienced any anomalies or malfunctions of the airplane prior to the loss of oil pressure. He also stated that he had read about the issue with the oil filter adapter a few weeks before the accident. Given that, “it had lasted this long,” he did not believe his installation was at issue.