Narrative:

Between june 2008 and dec 2008; I performed a number of repairs and maintenance items on a lycoming IO360-a1b6d in a cessna cardinal. During this entire repair session (several months); the aircraft owner also worked on his aircraft and engine; both independently by himself and alongside me. All engine work was completed by dec 2008. Initial test-runs were conducted by the owner as soon as this engine work was completed. All other airframe work was completed by dec 2008; with logbook entries written the same day. 4 days ago; I was contacted by the owner; who alleged that his engine had lost oil pressure inflight; that he declared an emergency and performed a successful emergency landing at an airport. He indicated that; during the landing; no property damage occurred; and no injuries occurred. He also alleged that paper towel fragments were found obstructing the oil suction screen; and that the engine was full of oil. The owner accused me of leaving one or more paper towel 'plugs' in vacant engine holes while work was being performed on the engine. The following tasks were performed on this engine by me; with the owner working alongside: 1) removed propeller; and reinstalled after overhaul. 2) removed and replaced single-drive dual magneto with overhauled unit. This task was done twice; as the first replacement magneto had thread problems from overhaul. 3) removed and reinstalled instrument suction (vacuum) pump to replace drive shear coupling. 4) removed and reinstalled propeller governor; because the previous installer had omitted a thin metal spacer between governor and governor adapter. A new spacer was installed with new gaskets. 5) flexible hoses for the fuel system; oil cooler; and engine instruments were removed and repaired (rubber portions replaced). The owner is not a licensed a&P mechanic. At the beginning; the owner was advised of the list of far-permitted owner-performed preventive maintenance tasks (in far 43); and was given use of the far books. During the months that this work was being performed; the owner was allowed unsupervised access to my hangar; to the tools; and to his airplane; for several hours per day. It is not known exactly what the owner did during those times. The owner did; while the engine was partially disassembled; clean several parts of the engine (including accessory case; oil sump; and inside the hollow crankshaft flange while the propeller was off); remove and install valve (rocker arm) covers; and made adjustments to the routing of hoses and wires. Paper towel plugs were installed in some vacant engine holes by the aircraft owner and by myself; to prevent entry of FOD. The owner also installed paper towel wadding in the valve spring areas of each cylinder to soak up dripping oil; while he had the valve covers off for several months. All paper plugs which I installed and later removed; came out cleanly and completely; during installation of the engine accessories. Inspection of the engine accessory mounting pads; prior to installation of each accessory; showed clean mounting pad areas with no residual paper towel material. After all of this work; a fairly thorough test-run program was conducted. This included several lengthy ground runs and several test-flights by the aircraft owner; of increasing duration. It is estimated that the engine had 4 hours of testing; perhaps more at this time (I do not have access to flight logs or current hobbs/tachometer numbers). There were no squawks relating to engine; vacuum pump; magneto; governor; or propeller function. The only squawk; a loose wire leading to the alternator; was quickly diagnosed and repaired. The owner took possession of the airplane; and kept it in a community hangar; while he continued flying it. The owner then left the airplane in the community hangar for approximately 3 weeks while he tended to a personal situation. He informed me of his plans to return to the airport; conduct additional test flights; and then head out. This was

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Original NASA ASRS Text

Title: A Mechanic with an Inspection Authority (IA) rating; reports on his involvement with repairs and maintenance on a Lycoming IO360 in a Cessna Cardinal that required an emergency landing. Owner/Operator also performed maintenance on the engine; but was not licensed.

Narrative: Between June 2008 and Dec 2008; I performed a number of repairs and maintenance items on a Lycoming IO360-A1B6D in a Cessna Cardinal. During this entire repair session (several months); the aircraft owner also worked on his aircraft and engine; both independently by himself and alongside me. All engine work was completed by Dec 2008. Initial test-runs were conducted by the owner as soon as this engine work was completed. All other airframe work was completed by Dec 2008; with logbook entries written the same day. 4 days ago; I was contacted by the owner; who alleged that his engine had lost oil pressure inflight; that he declared an emergency and performed a successful emergency landing at an airport. He indicated that; during the landing; no property damage occurred; and no injuries occurred. He also alleged that paper towel fragments were found obstructing the oil suction screen; and that the engine was full of oil. The owner accused me of leaving one or more paper towel 'plugs' in vacant engine holes while work was being performed on the engine. The following tasks were performed on this engine by me; with the owner working alongside: 1) Removed propeller; and reinstalled after overhaul. 2) Removed and replaced single-drive dual magneto with overhauled unit. This task was done twice; as the first replacement magneto had thread problems from overhaul. 3) Removed and reinstalled instrument suction (vacuum) pump to replace drive shear coupling. 4) Removed and reinstalled propeller governor; because the previous installer had omitted a thin metal spacer between governor and governor adapter. A new spacer was installed with new gaskets. 5) Flexible hoses for the fuel system; oil cooler; and engine instruments were removed and repaired (rubber portions replaced). The owner is not a licensed A&P Mechanic. At the beginning; the owner was advised of the list of FAR-permitted owner-performed preventive maintenance tasks (in FAR 43); and was given use of the FAR books. During the months that this work was being performed; the owner was allowed unsupervised access to my hangar; to the tools; and to his airplane; for several hours per day. It is not known exactly what the owner did during those times. The owner did; while the engine was partially disassembled; clean several parts of the engine (including accessory case; oil sump; and inside the hollow crankshaft flange while the propeller was off); remove and install valve (rocker arm) covers; and made adjustments to the routing of hoses and wires. Paper towel plugs were installed in some vacant engine holes by the aircraft owner and by myself; to prevent entry of FOD. The owner also installed paper towel wadding in the valve spring areas of each cylinder to soak up dripping oil; while he had the valve covers off for several months. All paper plugs which I installed and later removed; came out cleanly and completely; during installation of the engine accessories. Inspection of the engine accessory mounting pads; prior to installation of each accessory; showed clean mounting pad areas with no residual paper towel material. After all of this work; a fairly thorough test-run program was conducted. This included several lengthy ground runs and several test-flights by the aircraft owner; of increasing duration. It is estimated that the engine had 4 hours of testing; perhaps more at this time (I do not have access to flight logs or current Hobbs/tachometer numbers). There were no squawks relating to engine; vacuum pump; magneto; governor; or propeller function. The only squawk; a loose wire leading to the alternator; was quickly diagnosed and repaired. The owner took possession of the airplane; and kept it in a community hangar; while he continued flying it. The owner then left the airplane in the community hangar for approximately 3 weeks while he tended to a personal situation. He informed me of his plans to return to the airport; conduct additional test flights; and then head out. This was

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.