Narrative:

All indications were that the repair was airworthy; aircraft was flying fine and compression on the two new cylinders was good. After approximately 10-hours of flight time; the pilot reported that the engine was making a knocking noise and elected to land. The maintenance facility removed the rocker box cover on the suspected cylinder and found that the rocker arms were on the wrong side causing a misalignment. The cylinders were received from the overhaul facility and placed on the aircraft. I should have checked to make sure the correct part number was on the correct side. I assumed that they were. The plane landed without incident and the customer's aircraft is receiving warranty work.

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Original NASA ASRS Text

Title: An Aircraft Maintenance Technician (AMT) with Inspection Authority; reports a Piper PA28 Cherokee Six elected to land after the pilot reported the Lycoming IO-540 engine started making knocking noise. Two overhauled cylinders had been installed just ten flight hours earlier.

Narrative: All indications were that the repair was airworthy; aircraft was flying fine and compression on the two new cylinders was good. After approximately 10-hours of flight time; the pilot reported that the engine was making a knocking noise and elected to land. The Maintenance Facility removed the rocker box cover on the suspected cylinder and found that the rocker arms were on the wrong side causing a misalignment. The cylinders were received from the Overhaul Facility and placed on the aircraft. I should have checked to make sure the correct part number was on the correct side. I assumed that they were. The plane landed without incident and the customer's aircraft is receiving warranty work.

Data retrieved from NASA's ASRS site as of July 2013 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.