N578SP

HISTORY OF FLIGHTOn September 13, 2019, about 1545 eastern daylight time, a Cirrus SR22 airplane, N578SP, sustained substantial damage when it was involved in an accident near Hoagland, Indiana. The private pilot and passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot stated that he added 3/4 quart of oil before departing on the cross-country instrument flight rules flight. The oil pressure was about 41 to 42 pounds per square inch (psi) for the early part of the flight, then began to decrease into the 30 psi range. After the oil pressure dropped below 30 psi and the low oil pressure light came on, the pilot notified air traffic control that he would be diverting to a nearby airport. As the airplane descended from 10,000 ft and the pilot decreased engine power, the oil pressure increased above 30 psi and into the normal operating range by the time the airplane landed at the diversion airport. Flight information from the airplane's recoverable data module showed a recorded decrease in oil pressure and subsequent increase in oil pressure during the diversion, consistent with the pilot’s statement.

A post-flight check revealed that the engine contained about 6 quarts of oil, and two mechanics inspected the engine and checked for leaks. After confirming there were no signs of any oil leaks, they adjusted the sensor and turned the pressure relief valve one-quarter turn to tighten it. The engine was run at 1,600 rpm and the oil pressure read as high as 50 psi, with normal oil temperature indications. The recorded oil pressure during the engine ground run was consistent with the pilot’s statement. The pilot and passenger boarded the airplane, and the pilot conducted an engine run-up at 1,700 rpm. The oil pressure and temperature were “good,” and the pilot and passenger departed to continue the flight.

The pilot watched the oil pressure closely and stated that it indicated 45 psi for about the first 20 minutes of flight. Shortly thereafter, the engine lost all power, the red oil pressure light came on, and a few gauges on the avionics display showed large red Xs. The pilot immediately declared an emergency and asked for vectors to Fort Wayne International Airport (FWA), Fort Wayne, Indiana.

The pilot initiated the engine restart checklist while navigating to FWA; however, upon realizing that he would not reach the airport, he chose to activate the Cirrus Airframe Parachute System (CAPS). After the airplane came to rest in a plowed field, the pilot egressed and helped the passenger out.

The data from the accident flight revealed that the oil pressure was between 40 and 50 psi during the flight until about 39 minutes into the flight. At that point, the data showed that oil pressure, fuel flow, and engine rpm decreased to 0. There were subsequent changes in fuel flow consistent with the pilot’s attempts to restart the engine.

AIRCRAFT INFORMATIONAt the time of the annual inspection, the Hobbs meter indicated 3,891.5 hours, and the engine had accumulated 1,199.5 hours total time since new. The logbook entry for the annual inspection stated that the oil and filter were changed and that the filter was cut open and no abnormalities were noted. Additionally, the engine oil was analyzed routinely during oil changes. According to an oil analysis report dated May 29, 2019, the sample indicated the best “wear-rate” results from the engine; the amount of iron detected was a “bit” more than average for the type of engine, but “not far enough out of line to call a problem.”

According to the engine manufacturer’s maintenance manual directions current at the time of the accident, the minimum requirement is to change the oil and filter every 50 hours and/or 4 months on engines with full flow oil filters and on engines with a large or small replaceable oil filter cartridge. Manufacturer guidance stated that oil screens and filter elements should be inspected at each oil change, and that oil analysis may be used in addition to the oil screen or filter element inspection, but not as a replacement for inspection.

According to the engine’s illustrated parts catalogue, the accident engine type was equipped with a magnetic drain plug in the bottom drain hole of the oil sump pan and a quick drain coupling in a side port. Examination of the accident sump pan revealed that the magnetic drain plug was safety wired and mounted in the side port on the sump near the No. 1 cylinder and a quick drain coupling was mounted in the bottom drain hole.

A logbook entry showed that the engine oil was changed on August 4, 2019, at a Hobbs meter time of 3,900.4 hours. When asked if the magnetic drain plug or the oil filter were examined as part of the oil change, the mechanic who performed the oil change indicated that the accident airplane's engine was not equipped with a magnetic drain plug and that he did not examine the oil filter, since it had only been a few hours since the annual inspection.

The accident engine’s cylinders had not been removed since the engine was installed. An engine cylinder assembly includes a piston, piston pin, and connecting rod. The connecting rod components include a piston pin bushing and a connecting rod bearing. The steel-backed bronze piston pin bushing, part number 530658, is designed to have a split line, is pressed into the connecting rod, and its split line is clocked in a specified 45° arc.

Service Bulletin (SB)07-1, issued on March 19, 2007, current at the time of the accident, identified this arc. The purpose of this SB was “to provide inspection instructions for the connecting rod piston pin bushing,” and was directed “at each cylinder removal or anytime piston pin bushing material is identified during routine maintenance” procedures. The SB stated: “If piston pin bushing material is recovered from an engine, all of the cylinders, pistons, and piston pins must be removed to allow access for inspection of the connecting rods piston pin bushings.” The SB referenced a figure that showed a magnetic drain plug with an attracted bushing fragment as a typical indication of recovered bushing material.

The engine manufacturer issued Critical Service Bulletin (CSB) 07-1A and a maintenance manual Usua;lrevision after the accident. The CSB, revised September 2, 2020, updated SB07-1’s inspection instructions for the connecting rod piston pin bushing procedures and stated, “COMPLIANCE NECESSARY TO MAINTAIN SAFETY.” The CSB stated that during an oil change, a pre-cleaned catch basin should be placed beneath the oil sump drain and a 1000 micron or less (approximately 0.040” or less) mesh screen placed in the basin to strain the oil sump contents. The strainer, drain plug, and/or quick drain coupling should be examined for abnormal/excessive wear material, metal fragments, and debris to assess the engine condition. Metal fragments on the magnetic drain plug may indicate excessive wear or part damage.

The CSB contained a note that, in part, stated:

The quick drain coupling orifice may trap debris and sediment material. To prevent entrapped material and allow collection of ferrous particles, Continental strongly recommends removing the non-magnetic oil plug (Part No. 532432) or quick drain coupling (Part Nos. 656122, 656995, or 658764) and installing a magnetic drain plug (Part No. 636376 or 656169) in the oil sump to attract and collect ferrous (iron) wear particulate and larger particles that could contaminate the lubrication system. The presence and collection of material on the magnetic drain plug can: 1) indicate an issue with certain engine components; 2) prevent damage to the oil pump and; 3) capture particles that could become lodged in the oil pressure relief-valve and result in a low oil pressure event. Not all engines are equipped with quick drain couplings or magnetic drain plugs - check engine illustrated parts catalog for applicability.

AIRPORT INFORMATIONAt the time of the annual inspection, the Hobbs meter indicated 3,891.5 hours, and the engine had accumulated 1,199.5 hours total time since new. The logbook entry for the annual inspection stated that the oil and filter were changed and that the filter was cut open and no abnormalities were noted. Additionally, the engine oil was analyzed routinely during oil changes. According to an oil analysis report dated May 29, 2019, the sample indicated the best “wear-rate” results from the engine; the amount of iron detected was a “bit” more than average for the type of engine, but “not far enough out of line to call a problem.”

According to the engine manufacturer’s maintenance manual directions current at the time of the accident, the minimum requirement is to change the oil and filter every 50 hours and/or 4 months on engines with full flow oil filters and on engines with a large or small replaceable oil filter cartridge. Manufacturer guidance stated that oil screens and filter elements should be inspected at each oil change, and that oil analysis may be used in addition to the oil screen or filter element inspection, but not as a replacement for inspection.

According to the engine’s illustrated parts catalogue, the accident engine type was equipped with a magnetic drain plug in the bottom drain hole of the oil sump pan and a quick drain coupling in a side port. Examination of the accident sump pan revealed that the magnetic drain plug was safety wired and mounted in the side port on the sump near the No. 1 cylinder and a quick drain coupling was mounted in the bottom drain hole.

A logbook entry showed that the engine oil was changed on August 4, 2019, at a Hobbs meter time of 3,900.4 hours. When asked if the magnetic drain plug or the oil filter were examined as part of the oil change, the mechanic who performed the oil change indicated that the accident airplane's engine was not equipped with a magnetic drain plug and that he did not examine the oil filter, since it had only been ...